{
    "Ifc2DCompositeCurve": {
        "description": "An Ifc2DCompositeCurve is an IfcCompositeCurve that is defined within the coordinate space of an IfcPlane. Therefore the dimensionality of the Ifc2DCompositeCurve has to be 2.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifc2dcompositecurve.htm"
    },
    "IfcActionRequest": {
        "attributes": {
            "RequestID": "A unique identifier assigned to the request on receipt."
        },
        "description": "An IfcActionRequest is a request for an action to fulfill a need.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcactionrequest.htm"
    },
    "IfcActor": {
        "attributes": {
            "IsActingUpon": "Reference to the relationship that associates the actor to an object.",
            "TheActor": "Information about the actor."
        },
        "description": "The IfcActor defines all actors or human agents involved in a project during its full life cycle. It facilitates the use of person and organization definitions in the resource part of the IFC object model.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcactor.htm"
    },
    "IfcActorRole": {
        "attributes": {
            "Description": "A textual description relating the nature of the role played by an actor.",
            "Role": "The name of the role played by an actor. If the Role has value USERDEFINED, then the user defined role shall be provided as a value of the attribute UserDefinedRole.",
            "UserDefinedRole": "Allows for specification of user defined roles beyond the  enumeration values provided by Role attribute of type IfcRoleEnum.  When a value is provided for attribute UserDefinedRole in parallel  the attribute Role shall have enumeration value USERDEFINED."
        },
        "description": "A role which is performed by an actor, either a person, an organization or a person related to an organization.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcactorrole.htm"
    },
    "IfcActuatorType": {
        "description": "An IfcActuatorType defines a particular type of actuating device that is typically used in a control system such as a building automation control system.",
        "predefined_types": {
            "ELECTRICACTUATOR": "A device that electrically actuates a control element.",
            "HANDOPERATEDACTUATOR": "A device that manually actuates a control element.",
            "HYDRAULICACTUATOR": "A device that electrically actuates a control element.",
            "NOTDEFINED": "Undefined type.",
            "PNEUMATICACTUATOR": "A device that pneumatically actuates a control element.",
            "THERMOSTATICACTUATOR": "A device that thermostatically actuates a control element.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifcactuatortype.htm"
    },
    "IfcAddress": {
        "attributes": {
            "Description": "Text that relates the nature of the address.",
            "OfOrganization": "The inverse relationship to Organization to whom address is associated.",
            "OfPerson": "The inverse relationship to Person to whom address is associated.",
            "Purpose": "Identifies the logical location of the address.",
            "UserDefinedPurpose": "Allows for specification of user specific purpose of the address beyond the  enumeration values provided by Purpose attribute of type IfcAddressTypeEnum.  When a value is provided for attribute UserDefinedPurpose, in parallel the  attribute Purpose shall have enumeration value USERDEFINED."
        },
        "description": "An abstract entity type for various kinds of postal and telecom addresses.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcaddress.htm"
    },
    "IfcAirTerminalBoxType": {
        "description": "The element type IfcAirTerminalBoxType defines a list of commonly shared property set definitions of an air termainal box and an optional set of product representations. It is used to define an air terminal box specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "CONSTANTFLOW": "Terminal box does not include a means to reset the volume automatically to an outside signal such as thermostat.",
            "NOTDEFINED": "Undefined terminal box.",
            "USERDEFINED": "User-defined terminal box.",
            "VARIABLEFLOWPRESSUREDEPENDANT": "Terminal box includes a means to reset the volume automatically to a different control point in response to an outside signal such as thermostat: air-flow rate depends on supply pressure.",
            "VARIABLEFLOWPRESSUREINDEPENDANT": "Terminal box includes a means to reset the volume automatically to a different control point in response to an outside signal such as thermostat: air-flow rate is independant of supply pressure."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcairterminalboxtype.htm"
    },
    "IfcAirTerminalType": {
        "description": "The element type IfcAirTerminalType defines a list of commonly shared property set definitions of an air terminal and an optional set of product representations. It is used to define an air terminal specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "DIFFUSER": "An outlet discharging supply air in various directions and planes.",
            "EYEBALL": "",
            "GRILLE": "A covering for any area through which air passes.",
            "IRIS": "",
            "LINEARDIFFUSER": "",
            "LINEARGRILLE": "",
            "NOTDEFINED": "Undefined air terminal type.",
            "REGISTER": "A grille typically equipped with a damper or control valve.",
            "USERDEFINED": "User-defined air terminal type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcairterminaltype.htm"
    },
    "IfcAirToAirHeatRecoveryType": {
        "description": "The element type IfcAirToAirHeatRecoveryType defines a list of commonly shared property set definitions of an air-to-air heat recovery device and an optional set of product representations. It is used to define an air-to-air heat recovery device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "FIXEDPLATECOUNTERFLOWEXCHANGER": "Heat exchanger with moving parts and alternate layers of plates, separated and sealed from the exhaust and supply air stream passages with primary air entering at secondary air outlet location and exiting at secondary air inlet location.",
            "FIXEDPLATECROSSFLOWEXCHANGER": "Heat exchanger with moving parts and alternate layers of plates, separated and sealed from the exhaust and supply air stream passages with secondary air flow in the direction perpendicular to primary air flow.",
            "FIXEDPLATEPARALLELFLOWEXCHANGER": "Heat exchanger with moving parts and alternate layers of plates, separated and sealed from the exhaust and supply air stream passages with primary air entering at secondary air inlet location and exiting at secondary air outlet location.",
            "HEATPIPE": "A passive energy recovery device with a heat pipe divided into evaporator and condenser sections.",
            "NOTDEFINED": "Undefined air to air heat recovery type.",
            "ROTARYWHEEL": "A heat wheel with a revolving cylinder filled with an air-permeable medium having a large internal surface area.",
            "RUNAROUNDCOILLOOP": "A typical coil energy recovery loop places extended surface, finned tube water coils in the supply and exhaust airstreams of a building.",
            "THERMOSIPHONCOILTYPEHEATEXCHANGERS": "Sealed systems that consist of an evaporator, a condenser, interconnecting piping, and an intermediate working fluid that is present in both liquid and vapor phases where the evaporator and condensor coils are installed independently in the ducts and are interconnected by the working fluid piping.",
            "THERMOSIPHONSEALEDTUBEHEATEXCHANGERS": "Sealed systems that consist of an evaporator, a condenser, interconnecting piping, and an intermediate working fluid that is present in both liquid and vapor phases where the evaporator and the condenser are usually at opposite ends of a bundle of straight, individual thermosiphon tubes and the exhaust and supply ducts are adjacent to each other.",
            "TWINTOWERENTHALPYRECOVERYLOOPS": "An air-to-liquid, liquid-to-air enthalpy recovery system with a sorbent liquid circulates continuously between supply and exhaust airstreams, alternately contacting both airstreams directly in contactor towers.",
            "USERDEFINED": "User-defined air to air heat recovery type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcairtoairheatrecoverytype.htm"
    },
    "IfcAlarmType": {
        "description": "The IfcAlarmType defines a device that signals the existence of a condition or situation that is outside the boundaries of normal expectation or that activates such a device.",
        "predefined_types": {
            "BELL": "An audible alarm.",
            "BREAKGLASSBUTTON": "An alarm activation mechanism in which a protective glass has to be broken to enable a button to be pressed.",
            "LIGHT": "A visual alarm.",
            "MANUALPULLBOX": "An alarm activation mechanism in which activation is achieved by a pulling action.",
            "NOTDEFINED": "Undefined type.",
            "SIREN": "An audible alarm.",
            "USERDEFINED": "User-defined type.",
            "WHISTLE": "An audible alarm."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifcalarmtype.htm"
    },
    "IfcAngularDimension": {
        "description": "The angular dimension is a draughting callout that presents the plane angle measure between two non parallel orientations. It consists of a dimension curve and may have projection curves.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcangulardimension.htm"
    },
    "IfcAnnotation": {
        "attributes": {
            "ContainedInStructure": "Relationship to a spatial structure element, to which the associate is primarily associated."
        },
        "description": "An annotation is a graphical representation within the geometric (and spatial) context of a project, that adds a note or meaning to the objects which constitutes the project model. Annotations include additional line drawings, text, dimensioning, hatching and other forms of graphical notes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcannotation.htm"
    },
    "IfcAnnotationCurveOccurrence": {
        "description": "Definition from ISO/CD 10303-46:1992: An annotation curve occurrence is a curve with a style assignment.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationcurveoccurrence.htm"
    },
    "IfcAnnotationFillArea": {
        "attributes": {
            "InnerBoundaries": "A set of inner curves that define the inner boundaries of the fill area. The areas defined by the inner boundaries are excluded from applying the fill area style.",
            "OuterBoundary": "A closed curve that defines the outer boundary of the fill area. The areas defined by the outer boundary (minus potentially defined inner boundaries) is filled by the fill area style."
        },
        "description": "Definition from ISO/CD 10303-46:1992: An annotation fill area is a set of curves that may be filled with hatching, colour or tiling. The annotation fill are is described by boundaries which consist of non-intersecting, non-self-intersecting closed curves. These curves form the boundary of planar areas to be filled according to the style for the annotation fill area.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationfillarea.htm"
    },
    "IfcAnnotationFillAreaOccurrence": {
        "attributes": {
            "FillStyleTarget": "The point that specifies the starting location for the fill area style assigned to the annotation fill area occurrence. Depending on the attribute _GlobalOrLocal_ the point is either given within the world coordinate system of the project or within the object coordinate system of the element or annotation. If the _FillStyleTarget_ is not given, it defaults to 0.,0.",
            "GlobalOrLocal": "The coordinate system in which the _FillStyleTarget_ point is given. Depending on the attribute _GlobalOrLocal_ the point is either given within the world coordinate system of the project or within the object coordinate system of the element or annotation. If not given, the hatch style is directly applied to the parameterization of the geometric representation item, e.g. to the surface coordinate sytem, defined by the surface normal."
        },
        "description": "Definition from ISO/CD 10303-46:1992: An annotation fill area occurrence is a fill area with a style assignment.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationfillareaoccurrence.htm"
    },
    "IfcAnnotationOccurrence": {
        "description": "Definition from ISO/CD 10303-46:1992: The annotation occurrence entity is a geometric representation item which has style for presentation. This entity shall be used for annotation purposes only.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationoccurrence.htm"
    },
    "IfcAnnotationSurface": {
        "attributes": {
            "Item": "Geometric representation item, providing the geometric definition of the annotated surface. It is further restricted to be a surface, surface model, or solid model.",
            "TextureCoordinates": "Texture coordinates, such as a texture map, that are associated with the textures for the surface style. It should only be given, if the _IfcSurfaceStyle_ associated to the _IfcAnnotationSurfaceOccurrence_ contains an _IfcSurfaceStyleWithTextures_."
        },
        "description": "Definition from IAI: An IfcAnnotationSurface is a surface or solid with texture coordinates assigned. It provides the capabilities to assign",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationsurface.htm"
    },
    "IfcAnnotationSurfaceOccurrence": {
        "description": "Definition from IAI: The IfcAnnotationSurfaceOccurrence shall only be used within a material or paper space dependent representation (note: paper space is not yet supported within this IFC release). Styled surfaces or solids within model space shall use IfcStyledItem as the instance to link the geometric surface, solid or annotation surface (for texture maps) representation item to the (shared) style information.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationsurfaceoccurrence.htm"
    },
    "IfcAnnotationSymbolOccurrence": {
        "description": "Definition from ISO/CD 10303-46:1992: An annotation symbol occurrence is a symbol with a style assignment.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationsymboloccurrence.htm"
    },
    "IfcAnnotationTextOccurrence": {
        "description": "Definition from ISO/CD 10303-46:1992: An annotation text occurrence is a text with a style assignment.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcannotationtextoccurrence.htm"
    },
    "IfcApplication": {
        "attributes": {
            "ApplicationDeveloper": "Name of the application developer, being requested to be member of the IAI.",
            "ApplicationFullName": "The full name of the application as specified by the application developer.",
            "ApplicationIdentifier": "Short identifying name for the application.",
            "Version": "The version number of this software as specified by the developer of the application."
        },
        "description": "IfcApplication holds the information about an IFC compliant application developed by an application developer who is a member of the IAI. The IfcApplication utilizes a short identifying name as provided by the application developer.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcutilityresource/lexical/ifcapplication.htm"
    },
    "IfcAppliedValue": {
        "attributes": {
            "ApplicableDate": "The date on or from which an applied value is applicable.",
            "AppliedValue": "The extent or quantity or amount of an applied value.",
            "Description": "The description that may apply additional information about a cost (or impact) value. The description may be from purpose generated text, specification libraries, standards etc.",
            "FixedUntilDate": "The date until which applied value is applicable.",
            "IsComponentIn": "The value of the single applied value which is used by the applied value relationship to express a complex applied value.",
            "Name": "A name or additional clarification given to a cost (or impact) value.",
            "UnitBasis": "The number and unit of measure on which the unit cost is based.  Note: As well as the normally expected units of measure such as length, area, volume etc., costs may be based on units of measure which need to be defined e.g. sack, drum, pallet, item etc. Unit costs may be based on quantities greater (or lesser) than a unitary value of the basis measure. For instance, timber may have a unit cost rate per X meters where X > 1; similarly for cable, piping and many other items. The basis number may be either an integer or a real value.  Note: This attribute should be asserted for all circumstances where the cost to be applied is per unit quantity. It may be asserted even for circumstances where an item price is used, in which case the unit cost basis should be by item (or equivalent definition).",
            "ValueOfComponents": "The total (or subtotal) value of the components within the applied value relationship expressed as a single applied value.",
            "ValuesReferenced": "Pointer to the IfcReferencesCostDocument relationship, which refer to a document from which the cost value is referenced."
        },
        "description": "An IfcAppliedValue is an abstract supertype that specifies the common attributes for cost and environmental values that may be applied to objects within the IFC model.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcappliedvalue.htm"
    },
    "IfcAppliedValueRelationship": {
        "attributes": {
            "ArithmeticOperator": "The arithmetic operator applied in an applied value relationship.",
            "ComponentOfTotal": "The applied value (total or subtotal) of which the value being considered is a component.",
            "Components": "Applied values that are components of another applied value and from which that applied value may be deduced.",
            "Description": "A description that may apply additional information about an applied value relationship.",
            "Name": "A name used to identify or qualify the applied value relationship."
        },
        "description": "An IfcAppliedValueRelationship is a relationship class that enables applied values of cost or environmental impact to be aggregated together as components of another applied value.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcappliedvaluerelationship.htm"
    },
    "IfcApproval": {
        "attributes": {
            "Actors": "The set of relationships by which the actors acting in specified roles on this approval are known.",
            "ApprovalDateTime": "Date and time when the result of the approval process is produced.",
            "ApprovalLevel": "Level of the approval e.g. Draft v.s. Completed design.",
            "ApprovalQualifier": "Textual description of special constraints or conditions for the approval.",
            "ApprovalStatus": "The result or current status of the approval, e.g. Requested, Processed, Approved, Not Approved.",
            "Description": "A general textual description of a design, work task, plan, etc. that is being approved for.",
            "Identifier": "A computer interpretable identifier by which the approval is known.",
            "IsRelatedWith": "The set of relationships by which this approval is related to others.",
            "Name": "A human readable name given to an approval.",
            "Relates": "The set of relationships by which other approvals are related to this one."
        },
        "description": "An IfcApproval represents information about approval processes for a plan, a design, a proposal, a change order, etc, in a construction or facilities management project. IfcApproval is referenced by IfcRelAssociatesApproval in IfcControlExtension schema, and thereby can be related to all subtypes of IfcRoot.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcapprovalresource/lexical/ifcapproval.htm"
    },
    "IfcApprovalActorRelationship": {
        "attributes": {
            "Actor": "The reference to the actor who is acting in the given role on the approval specified in this relationship.",
            "Approval": "The approval on which the actor is acting in the role specified in this relationship.",
            "Role": "The role of the actor w.r.t the approval."
        },
        "description": "IfcApprovalActorRelationship is used for associating actors to approvals. An actor may be identified as a person or an organization, and may have a specified role in the approval process, e.g. either requesting or giving approval.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcapprovalresource/lexical/ifcapprovalactorrelationship.htm"
    },
    "IfcApprovalPropertyRelationship": {
        "attributes": {
            "Approval": "The approval for the properties selected.",
            "ApprovedProperties": "Properties approved by the approval."
        },
        "description": "IfcApprovalPropertyRelationship is used for associating an approval to properties. A single approval might be given to one or many instances of IfcProperty.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcapprovalresource/lexical/ifcapprovalpropertyrelationship.htm"
    },
    "IfcApprovalRelationship": {
        "attributes": {
            "Description": "Textual description explaining the relationship between approvals.",
            "Name": "The human readable name given to the relationship between the approvals.",
            "RelatedApproval": "The approval that relates to another approval",
            "RelatingApproval": "The approval that other approval is related to."
        },
        "description": "An IfcApprovalRelationship associates two approvals, having e.g. different status or level as approval process or the approved objects evolve.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcapprovalresource/lexical/ifcapprovalrelationship.htm"
    },
    "IfcArbitraryClosedProfileDef": {
        "attributes": {
            "OuterCurve": "Bounded curve, defining the outer boundaries of the arbitrary profile."
        },
        "description": "Definition from IAI: The closed profile IfcArbitraryClosedProfileDef defines an arbitrary two-dimensional profile for the use within the swept surface geometry, the swept area solid or a sectioned spine. It is given by an outer boundary from which the surface or solid can be constructed.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcarbitraryclosedprofiledef.htm"
    },
    "IfcArbitraryOpenProfileDef": {
        "attributes": {
            "Curve": "Open bounded curve defining the profile."
        },
        "description": "Definition from IAI: The open profile IfcArbitraryOpenProfileDef defines an arbitrary two-dimensional open profile for the use within the swept surface geometry. It is given by an open boundary from with the surface can be constructed.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcarbitraryopenprofiledef.htm"
    },
    "IfcArbitraryProfileDefWithVoids": {
        "attributes": {
            "InnerCurves": "Set of bounded curves, defining the inner boundaries of the arbitrary profile."
        },
        "description": "Definition from IAI: The IfcArbitraryProfileDefWithVoids defines an arbitrary closed two-dimensional profile with holes defined for the use for the swept area solid or a sectioned spine. It is given by an outer boundary and inner boundaries from with the solid the can be constructed.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcarbitraryprofiledefwithvoids.htm"
    },
    "IfcAsset": {
        "attributes": {
            "AssetID": "A unique identification assigned to an asset that enables its differentiation from other assets. NOTE: The asset identifier is unique within the asset register. It differs from the globally unique id assigned to the instance of an entity populating a database",
            "CurrentValue": "The current cost value of the asset.",
            "DepreciatedValue": "The current value of an asset within the accounting rules and procedures of an organization.",
            "IncorporationDate": "The date on which an asset was incorporated into the works, installed, constructed, erected or completed. NOTE: This is the date on which an asset is considered to start depreciating.",
            "OriginalValue": "The cost value of the asset at the time of purchase.",
            "Owner": "The name of the person or organization that 'owns' the asset.",
            "ResponsiblePerson": "The person designated to be responsible for the asset. NOTE: In (e.g.) UK Law (Health and Safety at Work Act, Electricity at Work Regulations, and others), management of assets must have a person identified as being responsible and to whom regulatory, insurance and other organizations communicate. In places where there is not a legal requirement, the responsible person would be the asset manager but would not have a legal status.",
            "TotalReplacementCost": "The total cost of replacement of the asset.",
            "User": "The name of the person or organization that 'uses' the asset."
        },
        "description": "An IfcAsset is a uniquely identifiable grouping of elements acting as a single entity that has a financial value",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcasset.htm"
    },
    "IfcAsymmetricIShapeProfileDef": {
        "attributes": {
            "CentreOfGravityInY": "Location of centre of gravity along the y axis measured from the center of the bounding box.",
            "TopFlangeFilletRadius": "The fillet between the web and the top flange of the I-shape. If given, the fillet between upper and the lower flanges and the web can be different. If not given, the value of the inherited FilletRadius attribute applies to both, the top and bottom fillet. If the inherited FilletRadius is not given either, no filler is applied.",
            "TopFlangeThickness": "Flange thickness of the top flange of the I-shape. If given, the upper and the lower flanges can have different thicknesses. If not given, the value of the inherited FlangeThickness attribute applies to both, the top and bottom flange thickness.",
            "TopFlangeWidth": "Extent of the top flange, defined parallel to the x axis of the position coordinate system."
        },
        "description": "Definition from IAI: The IfcAsymmetricIShapeProfileDef defines a section profile that provides the defining parameters of an asymmetric I-shaped section to be used by the swept area solid. The bottom flange is always wider than the top flange. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the gravity bounding box.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcasymmetricishapeprofiledef.htm"
    },
    "IfcAxis1Placement": {
        "attributes": {
            "Axis": "The direction of the local Z axis.",
            "Z": "The normalized direction of the local Z axis. It is either identical with the Axis value, if given, or it defaults to [0.,0.,1.] NVL (IfcNormalise(Axis), IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcDirection([0.0,0.0,1.0]))"
        },
        "description": "Definition from ISO/CD 10303-42:1992: The direction and location in three dimensional space of a single axis. An axis1_placement is defined in terms of a locating point (inherited from placement supertype) and an axis direction: this is either the direction of axis or defaults to (0.0,0.0,1.0). The actual direction for the axis placement is given by the derived attribute z (Z).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcaxis1placement.htm"
    },
    "IfcAxis2Placement2D": {
        "attributes": {
            "P": "P[1]: The normalized direction of the placement X Axis. This is (1.0,0.0,0.0) if RefDirection is omitted. P[2]: The normalized direction of the placement Y Axis. This is a derived attribute and is orthogonal to P[1]. IfcBuild2Axes(RefDirection)",
            "RefDirection": "The direction used to determine the direction of the local X Axis."
        },
        "description": "Definition from ISO/CD 10303-42:1992: The location and orientation in two dimensional space of two mutually perpendicular axes. An axis2_placement_2d is defined in terms of a point, (inherited from the placement supertype), and an axis. It can be used to locate and originate an object in two dimensional space and to define a placement coordinate system. The class includes a point which forms the origin of the placement coordinate system. A direction vector is required to complete the definition of the placement coordinate system. The reference direction defines the placement X axis direction, the placement Y axis is derived from this.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcaxis2placement2d.htm"
    },
    "IfcAxis2Placement3D": {
        "attributes": {
            "Axis": "The exact direction of the local Z Axis.",
            "P": "The normalized directions of the placement X Axis (P[1]) and the placement Y Axis (P[2]) and the placement Z Axis (P[3]). IfcBuildAxes(Axis, RefDirection)",
            "RefDirection": "The direction used to determine the direction of the local X Axis. If necessary an adjustment is made to maintain orthogonality to the Axis direction. If Axis and/or RefDirection is omitted, these directions are taken from the geometric coordinate system."
        },
        "description": "Definition from ISO/CD 10303-42:1992: The location and orientation in three dimensional space of three mutually perpendicular axes. An axis2_placement_3D is defined in terms of a point (inherited from placement supertype) and two (ideally orthogonal) axes. It can be used to locate and originate an object in three dimensional space and to define a placement coordinate system. The entity includes a point which forms the origin of the placement coordinate system. Two direction vectors are required to complete the definition of the placement coordinate system. The axis is the placement Z axis direction and the ref_direction is an approximation to the placement X axis direction.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcaxis2placement3d.htm"
    },
    "IfcBSplineCurve": {
        "attributes": {
            "ClosedCurve": "Indication of whether the curve is closed; it is for information only.",
            "ControlPoints": "The array of control points used to define the geometry of the curve. This is derived from the list of control points. IfcListToArray(ControlPointsList,0,UpperIndexOnControlPoints)",
            "ControlPointsList": "The list of control points for the curve.",
            "CurveForm": "Used to identify particular types of curve; it is for information only.",
            "Degree": "The algebraic degree of the basis functions.",
            "SelfIntersect": "Indication whether the curve self-intersects or not; it is for information only.",
            "UpperIndexOnControlPoints": "The upper index on the array of control points; the lower index is 0. This value is derived from the control points list. (SIZEOF(ControlPointsList) - 1)"
        },
        "description": "Definition from ISO/CD 10303-42:1992: A B-spline curve is a piecewise parametric polynomial or rational curve described in terms of control points and basis functions. The B-spline curve has been selected as the most stable format to represent all types of polynomial or rational parametric curves. With appropriate attribute values it is capable of representing single span or spline curves of explicit polynomial, rational, Bezier or B-spline type.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcbsplinecurve.htm"
    },
    "IfcBeam": {
        "description": "Definition from ISO 6707-1:1989: Structural member designed to carry loads between or beyond points of support, usually narrow in relation to its length and horizontal or nearly so.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcbeam.htm"
    },
    "IfcBeamType": {
        "description": "The element type (IfcBeamType) defines a list of commonly shared property set definitions of a beam and an optional set of product representations. It is used to define a beam specification (i.e. the specific product information that is common to all occurrences of that product type).",
        "predefined_types": {
            "BEAM": "A standard beam usually used horizontally.",
            "JOIST": "A beam used to support a floor or ceiling.",
            "LINTEL": "A beam or horizontal piece of material over an opening (e.g. door, window).",
            "NOTDEFINED": "Undefined linear beam element.",
            "T_BEAM": "A beam that forms part of a slab construction and acts together with the slab which its carries. Such beams are often of T-shape (therefore the English name), but may have other shapes as well, e.g. an L-Shape or an Inverted-T-Shape.",
            "USERDEFINED": "User-defined linear beam element."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcbeamtype.htm"
    },
    "IfcBezierCurve": {
        "description": "Definition from ISO/CD 10303-42:1992: This is a special type of curve which can be represented as a type of B-spline curve in which the knots are evenly spaced and have high multiplicities. Suitable default values for the knots and knot multiplicities are derived in this case.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcbeziercurve.htm"
    },
    "IfcBlobTexture": {
        "attributes": {
            "RasterCode": "Blob, given as a single binary, to capture the texture within one popular file (compression) format.",
            "RasterFormat": "The format of the _RasterCode_ often using a compression."
        },
        "description": "An IfcBlobTexture provides a 2-dimensional distribution of the lighting parameters of a surface onto which it is mapped. The texture itself is given as a single binary, representing the content of a pixel format. The file format of the pixel file is given by the RasterFormat attribute and allowable formats are guided by where rule WR41.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcblobtexture.htm"
    },
    "IfcBlock": {
        "attributes": {
            "XLength": "The size of the block along the placement X axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[1]_.",
            "YLength": "The size of the block along the placement Y axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[2]_.",
            "ZLength": "The size of the block along the placement Z axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[3]_."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A block is a solid rectangular parallelepiped, defined with a location and placement coordinate system. The block is specified by the positive lengths x, y, and z along the axes of the placement coordinate system, and has one vertex at the origin of the placement coordinate system.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcblock.htm"
    },
    "IfcBoilerType": {
        "description": "The element type IfcBoilerType defines a list of commonly shared property set definitions of a boiler and an optional set of product representations. It is used to define a boiler specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "NOTDEFINED": "Undefined Boiler type.",
            "STEAM": "Steam boiler.",
            "USERDEFINED": "User-defined Boiler type.",
            "WATER": "Water boiler."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcboilertype.htm"
    },
    "IfcBooleanClippingResult": {
        "description": "A clipping result is defined as a special subtype of the general Boolean result (IfcBooleanResult). It constrains the operands and the operator of the Boolean result.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcbooleanclippingresult.htm"
    },
    "IfcBooleanResult": {
        "attributes": {
            "Dim": "The space dimensionality of this entity. It is identical with the space dimensionality of the first operand. A where rule ensures that both operands have the same space dimensionality. FirstOperand.Dim",
            "FirstOperand": "The first operand to be operated upon by the Boolean operation.",
            "Operator": "The Boolean operator used in the operation to create the result.",
            "SecondOperand": "The second operand specified for the operation."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A Boolean result is the result of a regularized operation on two solids to create a new solid. Valid operations are regularized union, regularized intersection, and regularized difference. For purpose of Boolean operations, a solid is considered to be a regularized set of points. The final Boolean result depends upon the operation and the two operands. In the case of the difference operator the order of the operands is also significant. The operator can be either union, intersection or difference. The effect of these operators is described below:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcbooleanresult.htm"
    },
    "IfcBoundaryCondition": {
        "attributes": {
            "Name": "Optionally defines a name for this boundary condition."
        },
        "description": "Definition from IAI: The abstract entity IfcBoundaryCondition is the supertype of all boundary conditions that can be applied to structural connection definitions, either directly for the connection (e.g. the joint) or for the relation between a structural member and the connection.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcboundarycondition.htm"
    },
    "IfcBoundaryEdgeCondition": {
        "attributes": {
            "LinearStiffnessByLengthX": "Linear stiffness value in x-direction of the coordinate system defined by the instance which uses this resource object.",
            "LinearStiffnessByLengthY": "Linear stiffness value in y-direction of the coordinate system defined by the instance which uses this resource object.",
            "LinearStiffnessByLengthZ": "Linear stiffness value in z-direction of the coordinate system defined by the instance which uses this resource object.",
            "RotationalStiffnessByLengthX": "Rotational stiffness value about the x-axis of the coordinate system defined by the instance which uses this resource object.",
            "RotationalStiffnessByLengthY": "Rotational stiffness value about the y-axis of the coordinate system defined by the instance which uses this resource object.",
            "RotationalStiffnessByLengthZ": "Rotational stiffness value about the z-axis of the coordinate system defined by the instance which uses this resource object."
        },
        "description": "Definition from IAI: The entity IfcBoundaryEdgeCondition describes boundary conditions that can be applied to structural edge connections, either directly for the connection (e.g. the connecting edge) or for the relation between a structural member and the connection.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcboundaryedgecondition.htm"
    },
    "IfcBoundaryFaceCondition": {
        "attributes": {
            "LinearStiffnessByAreaX": "Linear stiffness value in x-direction of the coordinate system defined by the instance which uses this resource object.",
            "LinearStiffnessByAreaY": "Linear stiffness value in y-direction of the coordinate system defined by the instance which uses this resource object.",
            "LinearStiffnessByAreaZ": "Linear stiffness value in z-direction of the coordinate system defined by the instance which uses this resource object."
        },
        "description": "Definition from IAI: The entity IfcBoundaryFaceCondition describes boundary conditions that can be applied to structural face connections, either directly for the connection (e.g. the connecting face) or for the relation between a structural member and the connection.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcboundaryfacecondition.htm"
    },
    "IfcBoundaryNodeCondition": {
        "attributes": {
            "LinearStiffnessX": "Linear stiffness value in x-direction of the coordinate system defined by the instance which uses this resource object.",
            "LinearStiffnessY": "Linear stiffness value in y-direction of the coordinate system defined by the instance which uses this resource object.",
            "LinearStiffnessZ": "Linear stiffness value in z-direction of the coordinate system defined by the instance which uses this resource object.",
            "RotationalStiffnessX": "Rotational stiffness value about the x-axis of the coordinate system defined by the instance which uses this resource object.",
            "RotationalStiffnessY": "Rotational stiffness value about the y-axis of the coordinate system defined by the instance which uses this resource object.",
            "RotationalStiffnessZ": "Rotational stiffness value about the z-axis of the coordinate system defined by the instance which uses this resource object."
        },
        "description": "Definition from IAI: The entity IfcBoundaryNodeCondition describes boundary conditions that can be applied to structural point connections, either directly for the connection (e.g. the joint) or for the relation between a structural member and the connection. ",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcboundarynodecondition.htm"
    },
    "IfcBoundaryNodeConditionWarping": {
        "attributes": {
            "WarpingStiffness": "Defines the warping stiffness value."
        },
        "description": "IfcBoundaryNodeConditionWarping inherits all attributes from IfcBoundaryNodeCondition and includes additionally the possibility to define a value describing the warping stiffness.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcboundarynodeconditionwarping.htm"
    },
    "IfcBoundedCurve": {
        "description": "Definition from ISO/CD 10303-42:1992: A bounded curve is a curve of finite arc length with identifiable end points.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcboundedcurve.htm"
    },
    "IfcBoundedSurface": {
        "description": "Definition from ISO/CD 10303-42:1992: A bounded surface is a surface of finite area with identifiable boundaries.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcboundedsurface.htm"
    },
    "IfcBoundingBox": {
        "attributes": {
            "Corner": "Location of the bottom left corner (having the minimum values).",
            "Dim": "The space dimensionality of this class, it is always 3. 3",
            "XDim": "Length attribute (measured along the edge parallel to the X Axis)",
            "YDim": "Width attribute (measured along the edge parallel to the Y Axis)",
            "ZDim": "Height attribute (measured along the edge parallel to the Z Axis)."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A box domain is an orthogonal box parallel to the axes of the geometric coordinate system which may be used to limit the domain of a half space solid. A box domain is specified by the coordinates of the bottom left corner, and the lengths of the sides measured in the directions of the coordinate axes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcboundingbox.htm"
    },
    "IfcBoxedHalfSpace": {
        "attributes": {
            "Enclosure": "The box which bounds the half space for computational purposes only."
        },
        "description": "Definition from ISO/CD 10303-42:1992: This entity is a subtype of the half space solid which is trimmed by a surrounding rectangular box. The box has its edges parallel to the coordinate axes of the geometric coordinate system.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcboxedhalfspace.htm"
    },
    "IfcBuilding": {
        "attributes": {
            "BuildingAddress": "Address given to the building for postal purposes.",
            "ElevationOfRefHeight": "Elevation above sea level of the reference height used for all storey elevation measures, equals to height 0.0. It is usually the ground floor level.",
            "ElevationOfTerrain": "Elevation above the minimal terrain level around the foot print of the building, given in elevation above sea level."
        },
        "description": "Definition from ISO 6707-1:1989: Construction work that has the provision of shelter for its occupants or contents as one of its main purpose and is normally designed to stand permanently in one place.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuilding.htm"
    },
    "IfcBuildingElement": {
        "description": "Definition from ISO 6707-1:1989: Major functional part of a building, examples are foundation, floor, roof, wall.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingelement.htm"
    },
    "IfcBuildingElementComponent": {
        "description": "A building element component represents items included in building elements, which usually are not of interest from the overall building structure viewpoint. Contrary to accessories these components form a significant part of the building elements they belong to and usually have a vital and load carrying function within the structure. Typical examples of _IfcBuildingElementComponent_s include different kinds of reinforcing elements, layers of sandwich wall panels, and plates as parts of structural members.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcbuildingelementcomponent.htm"
    },
    "IfcBuildingElementPart": {
        "description": "Layers or major components as subordinate parts of a building element. Typical usage examples include precast concrete sandwich walls, where the layers may have different geometry representations. In this case the layered material representation does not sufficiently describe the element. Each layer is represented by an own instance of the IfcBuildingElementPart with its own geometry description.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcbuildingelementpart.htm"
    },
    "IfcBuildingElementProxy": {
        "attributes": {
            "CompositionType": "Indication, whether the proxy is intended to form an aggregation (COMPLEX), an integral element (ELEMENT), or a part in an aggregation (PARTIAL)."
        },
        "description": "The IfcBuildingElementProxy is a proxy definition that provides the same functionality as an IfcBuildingElement, but without having a defined meaning of the special type of building element, it represents.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingelementproxy.htm"
    },
    "IfcBuildingElementProxyType": {
        "description": "The IfcBuildingElementProxyType defines a list of commonly shared property set definitions of a building element proxy and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "NOTDEFINED": "Undefined building element proxy.",
            "USERDEFINED": "User-defined building element proxy."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingelementproxytype.htm"
    },
    "IfcBuildingElementType": {
        "description": "The element type (IfcBuildingElementType) defines a list of commonly shared property set definitions of a building element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingelementtype.htm"
    },
    "IfcBuildingStorey": {
        "attributes": {
            "Elevation": "Elevation of the base of this storey, relative to the 0,00 internal reference height of the building. The 0.00 level is given by the absolute above sea level height by the ElevationOfRefHeight attribute given at IfcBuilding."
        },
        "description": "The building storey has an elevation and typically represents a (nearly) horizontal aggregation of spaces that are vertically bound.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcbuildingstorey.htm"
    },
    "IfcCShapeProfileDef": {
        "attributes": {
            "CentreOfGravityInX": "Location of centre of gravity along the x axis measured from the center of the bounding box.",
            "Depth": "Profile depth, see illustration above (= h).",
            "Girth": "Lengths of girth, see illustration above (= c).",
            "InternalFilletRadius": "Internal fillet radius according the above illustration (= r1). If it is not given, zero is assumed.",
            "WallThickness": "Constant wall thickness of profile (= ts).",
            "Width": "Profile width, see illustration above (= b)."
        },
        "description": "The IfcCShapeProfileDef defines a section profile that provides the defining parameters of a C-shaped section to be used by the swept area solid. This section is typically produced by cold forming steel. Its parameters and orientation relative to the position coordinate system are according to the following illustration.The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccshapeprofiledef.htm"
    },
    "IfcCableCarrierFittingType": {
        "description": "An IfcCableCarrierFittingType defines a particular type of cable carrier fitting which is a fitting that is placed at junction or transition in a cable carrier system.",
        "predefined_types": {
            "BEND": "A fitting that changes the route of the cable carrier.",
            "CROSS": "A fitting at which two branches are taken from the main route of the cable carrier simultaneously.",
            "NOTDEFINED": "Undefined type.",
            "REDUCER": "A fitting that changes the physical size of the main route of the cable carrier.",
            "TEE": "A fitting at which a branch is taken from the main route of the cable carrier.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifccablecarrierfittingtype.htm"
    },
    "IfcCableCarrierSegmentType": {
        "description": "The IfcCableCarrierSegmentType is a flow segment that is specifically used to carry and support cabling.",
        "predefined_types": {
            "CABLELADDERSEGMENT": "An open carrier segment on which cables are carried on a ladder structure.",
            "CABLETRAYSEGMENT": "A (typically) open carrier segment onto which cables are laid.",
            "CABLETRUNKINGSEGMENT": "An enclosed carrier segment with one or more compartments into which cables are placed.",
            "CONDUITSEGMENT": "An enclosed tubular carrier segment through which cables are pulled.",
            "NOTDEFINED": "Undefined type.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifccablecarriersegmenttype.htm"
    },
    "IfcCableSegmentType": {
        "description": "An IfcCableSegmentType is a type of flow segment used to carry electrical power or communications signals.",
        "predefined_types": {
            "CABLESEGMENT": "Cable with a specific purpose to lead electric current within a circuit or any other electric construction. Includes all types of electric cables, mainly several core segments or conductor segments wrapped together.",
            "CONDUCTORSEGMENT": "A single linear element within a cable or an exposed wire (such as for grounding) with the specific purpose to lead electric current, data, or a telecommunications signal.",
            "NOTDEFINED": "Undefined type.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifccablesegmenttype.htm"
    },
    "IfcCalendarDate": {
        "attributes": {
            "DayComponent": "The day element of the calendar date.",
            "MonthComponent": "The month element of the calendar date.",
            "YearComponent": "The year element of the calendar date."
        },
        "description": "Definition from ISO/CD 10303-41:1992: A date which is defined by a day in a month of a year.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifccalendardate.htm"
    },
    "IfcCartesianPoint": {
        "attributes": {
            "Coordinates": "The first, second, and third coordinate of the point location. If placed in a two or three dimensional rectangular Cartesian coordinate system, Coordinates[1] is the X coordinate, Coordinates[2] is the Y coordinate, and Coordinates[3] is the Z coordinate.",
            "Dim": "The space dimensionality of this class, determined by the number of coordinates in the List of Coordinates. HIINDEX(Coordinates)"
        },
        "description": "Definition from ISO/CD 10303-42:1992: A point defined by its coordinates in a two or three dimensional rectangular Cartesian coordinate system, or in a two dimensional parameter space. The entity is defined in a two or three dimensional space.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccartesianpoint.htm"
    },
    "IfcCartesianTransformationOperator": {
        "attributes": {
            "Axis1": "The direction used to determine U[1], the derived X axis direction.",
            "Axis2": "The direction used to determine U[2], the derived Y axis direction.",
            "Dim": "The space dimensionality of this class, determined by the space dimensionality of the local origin. LocalOrigin.Dim",
            "LocalOrigin": "The required translation, specified as a cartesian point. The actual translation included in the transformation is from the geometric origin to the local origin.",
            "Scale": "The scaling value specified for the transformation.",
            "Scl": "The derived scale S of the transformation, equal to scale if that exists, or 1.0 otherwise. NVL(Scale, 1.0)"
        },
        "description": "Definition from ISO/CD 10303-42:1992: A Cartesian transformation operator defines a geometric transformation composed of translation, rotation, mirroring and uniform scaling. The list of normalized vectors u defines the columns of an orthogonal matrix T. These vectors are computed, by the base axis function, from the direction attributes axis1, axis2 and, in Cartesian transformation operator 3d, axis3. If |T|= -1, the transformation includes mirroring. The local origin point A, the scale value S and the matrix T together define a transformation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccartesiantransformationoperator.htm"
    },
    "IfcCartesianTransformationOperator2D": {
        "attributes": {
            "U": "The list of mutually orthogonal, normalized vectors defining the transformation matrix T. They are derived from the explicit attributes Axis1 and Axis2 in that order. IfcBaseAxis(2,SELF\\IfcCartesianTransformationOperator.Axis1, SELF\\IfcCartesianTransformationOperator.Axis2,?)"
        },
        "description": "Definition from ISO/CD 10303-42:1992: A Cartesian transformation operator 2d defines a geometric transformation in two-dimensional space composed of translation, rotation, mirroring and uniform scaling. The list of normalized vectors u defines the columns of an orthogonal matrix T. These vectors are computed from the direction attributes axis1 and axis2 by the base axis function. If |T|= -1, the transformation includes mirroring.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccartesiantransformationoperator2d.htm"
    },
    "IfcCartesianTransformationOperator2DnonUniform": {
        "attributes": {
            "Scale2": "The scaling value specified for the transformation along the axis 2. This is normally the y scale factor.",
            "Scl2": "The derived scale S(2) of the transformation along the axis 2 (normally the y axis), equal to Scale2 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise. NVL(Scale2, SELF\\IfcCartesianTransformationOperator.Scl)"
        },
        "description": "A Cartesian transformation operator 2d non uniform defines a geometric transformation in two-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by two different scaling factors:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccartesiantransformationoperator2dnonuniform.htm"
    },
    "IfcCartesianTransformationOperator3D": {
        "attributes": {
            "Axis3": "The exact direction of U[3], the derived Z axis direction.",
            "U": "The list of mutually orthogonal, normalized vectors defining the transformation matrix T. They are derived from the explicit attributes Axis3, Axis1, and Axis2 in that order. IfcBaseAxis(3,SELF\\IfcCartesianTransformationOperator.Axis1, SELF\\IfcCartesianTransformationOperator.Axis2,Axis3)"
        },
        "description": "Definition from ISO/CD 10303-42:1992: A Cartesian transformation operator 3d defines a geometric transformation in three-dimensional space composed of translation, rotation, mirroring and uniform scaling. The list of normalized vectors u defines the columns of an orthogonal matrix T. These vectors are computed from the direction attributes axis1, axis2 and axis3 by the base axis function. If |T|= -1, the transformation includes mirroring.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccartesiantransformationoperator3d.htm"
    },
    "IfcCartesianTransformationOperator3DnonUniform": {
        "attributes": {
            "Scale2": "The scaling value specified for the transformation along the axis 2. This is normally the y scale factor.",
            "Scale3": "The scaling value specified for the transformation along the axis 3. This is normally the z scale factor.",
            "Scl2": "The derived scale S(2) of the transformation along the axis 2 (normally the y axis), equal to Scale2 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise. NVL(Scale2, SELF\\IfcCartesianTransformationOperator.Scl)",
            "Scl3": "The derived scale S(3) of the transformation along the axis 3 (normally the z axis), equal to Scale3 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise. NVL(Scale3, SELF\\IfcCartesianTransformationOperator.Scl)"
        },
        "description": "A Cartesian transformation operator 3d non uniform defines a geometric transformation in three-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by three different scaling factors:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccartesiantransformationoperator3dnonuniform.htm"
    },
    "IfcCenterLineProfileDef": {
        "attributes": {
            "Thickness": "Constant thickness applied along the center line."
        },
        "description": "The profile IfcCenterLineProfileDef defines an arbitrary two-dimensional open, not self intersecting profile for the use within the swept solid geometry. It is given by an area defined by applying a constant thickness to a centerline, generating an area from which the solid can be constructed.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccenterlineprofiledef.htm"
    },
    "IfcChamferEdgeFeature": {
        "attributes": {
            "Height": "The height of the feature chamfer cross section.",
            "Width": "The width of the feature chamfer cross section."
        },
        "description": "An edge feature with a chamfered cross section shape.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcchamferedgefeature.htm"
    },
    "IfcChillerType": {
        "description": "The element type IfcChillerType defines a list of commonly shared property set definitions of a chiller and an optional set of product representations. It is used to define a chiller specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "AIRCOOLED": "Air cooled chiller.",
            "HEATRECOVERY": "Heat recovery chiller.",
            "NOTDEFINED": "Undefined chiller type.",
            "USERDEFINED": "User-defined chiller type.",
            "WATERCOOLED": "Water cooled chiller."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcchillertype.htm"
    },
    "IfcCircle": {
        "attributes": {
            "Radius": "The radius of the circle, which shall be greater than zero."
        },
        "description": "Definition from ISO/CD 10303-42:1992: An IfcCircle is defined by a radius and the location and orientation of the circle. Interpretation of data should be as follows:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccircle.htm"
    },
    "IfcCircleHollowProfileDef": {
        "attributes": {
            "WallThickness": "Thickness of the material, it is the difference between the outer and inner radius."
        },
        "description": "Definition from IAI: The IfcCircleHollowProfileDef defines a section profile that provides the defining parameters of a circular hollow section (tube) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration.The centre of the position coordinate system is in the profile's centre of the bounding box (for symmetric profiles identical with the centre of gravity).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccirclehollowprofiledef.htm"
    },
    "IfcCircleProfileDef": {
        "attributes": {
            "Radius": "The radius of the circle."
        },
        "description": "Definition from IAI: The IfcCircleProfileDef defines a circle as the profile definition used by the swept surface geometry or by the swept area solid. It is given by its Radius attribute and placed within the 2D position coordinate system, established by the Position attribute.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccircleprofiledef.htm"
    },
    "IfcClassification": {
        "attributes": {
            "Contains": "Classification items that are classified by the classification.",
            "Edition": "The edition or version of the classification system from which the classification notation is derived.",
            "EditionDate": "The date on which the edition of the classification used became valid. NOTE: The indication of edition may be sufficient to identify the classification source uniquely but the edition date is provided as an optional attribute to enable more precise identification where required.",
            "Name": "The name or label by which the classification used is normally known. NOTE: Examples of names include CI/SfB, Masterformat, BSAB, Uniclass, STABU etc.",
            "Source": "Source (or publisher) for this classification."
        },
        "description": "An IfcClassification is used for the arrangement of objects into a class or category according to a common purpose or their possession of common characteristics.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassification.htm"
    },
    "IfcClassificationItem": {
        "attributes": {
            "IsClassifiedItemIn": "Identifies the relationship in which the role of ClassifiedItem is taken.",
            "IsClassifyingItemIn": "Identifies the relationship in which the role of ClassifyingItem is taken.",
            "ItemOf": "The classification that is the source for the uppermost level of the classification item hierarchy used. NOTE: Where a classification item hierarchy is developed within the IFC model, only the uppermost level needs to refer to the classification system or source from which it is derived since all other levels of the hierachy will refer to the source by virtue of their containment by the uppermost level. However, the uppermost level MUST point back to the classification source by virtue of the fact that it is not contained by a higher level classification item.",
            "Notation": "The notations from within a classification item that are used within the project. NOTE: In Uniclass this label is called the Code, in UDC it is called the Class Number.",
            "Title": "The name of the classification item. NOTE: Examples of the above attributes from Uniclass:  A classification item in Uniclass has a notation \"L6814\" which has the title \"Tanking\". It has a parent notation \"L681\" which has the title \"Proofings, insulation\"."
        },
        "description": "An IfcClassificationItem is a class of classification notations used.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationitem.htm"
    },
    "IfcClassificationItemRelationship": {
        "attributes": {
            "RelatedItems": "The child level items in a classification structure that are related to the parent level item.",
            "RelatingItem": "The parent level item in a classification structure that is used for relating the child level items."
        },
        "description": "An IfcClassificationItemRelationship is a relationship class that enables the hierarchical structure of a classification system to be exposed through its ability to contain related classification items and to be contained by a relating classification item.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationitemrelationship.htm"
    },
    "IfcClassificationNotation": {
        "attributes": {
            "NotationFacets": "Alphanumeric characters in defined groups from which the classification notation is derived."
        },
        "description": "An IfcClassificationNotation is a notation used from published reference (which may be either publicly available from a classification society or is published locally for the purposes of an organization, project or other purpose).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationnotation.htm"
    },
    "IfcClassificationNotationFacet": {
        "attributes": {
            "NotationValue": "The notation value that specifies the classification e.g. 'L781'"
        },
        "description": "An IfcClassificationNotationFacet is a group of alphanumeric characters used within a classification notation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationnotationfacet.htm"
    },
    "IfcClassificationReference": {
        "attributes": {
            "ReferencedSource": "The classification system or source that is referenced."
        },
        "description": "An IfcClassificationReference is a reference into a classification system or source (see IfcClassification). An optional inherited ItemReference key is also provided to allow more specific references to classification items (or tables) by type. The inherited Name attribute allows for a human interpretable designation of a classification notation (or code) - see use definition of \"Lightweight Classification\".",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcclassificationreference.htm"
    },
    "IfcClosedShell": {
        "description": "Definition from ISO/CD 10303-42:1992: A closed shell is a shell of the dimensionality 2 which typically serves as a bound for a region in R3. A closed shell has no boundary, and has non-zero finite extent. If the shell has a domain with coordinate space R3, it divides that space into two connected regions, one finite and the other infinite. In this case, the topological normal of the shell is defined as being directed from the finite to the infinite region.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcclosedshell.htm"
    },
    "IfcCoilType": {
        "description": "The element type IfcCoilType defines a list of commonly shared property set definitions of a coil and an optional set of product representations. It is used to define a coil specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "DXCOOLINGCOIL": "Cooling coil using a refrigerant to cool the air stream directly.",
            "ELECTRICHEATINGCOIL": "Heating coil using electricity as a heating source.",
            "GASHEATINGCOIL": "Heating coil using gas as a heating source.",
            "NOTDEFINED": "Undefined coil type.",
            "STEAMHEATINGCOIL": "Heating coil using steam as heating source.",
            "USERDEFINED": "User-defined coil type.",
            "WATERCOOLINGCOIL": "Cooling coil using chilled water. HYDRONICCOIL supercedes this enumerator.",
            "WATERHEATINGCOIL": "Heating coil using hot water as a heating source. HYDRONICCOIL supercedes this enumerator."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccoiltype.htm"
    },
    "IfcColourRgb": {
        "attributes": {
            "Blue": "The intensity of the blue colour component. >  NOTE  The colour component value is given within the range of 0..1, and not within the range of 0..255 as otherwise usual.",
            "Green": "The intensity of the green colour component. >  NOTE  The colour component value is given within the range of 0..1, and not within the range of 0..255 as otherwise usual.",
            "Red": "The intensity of the red colour component. >  NOTE  The colour component value is given within the range of 0..1, and not within the range of 0..255 as otherwise usual."
        },
        "description": "Definition from ISO/CD 10303-46:1992: A colour rgb as a subtype of colour specifications is defined by three colour component values for red, green, and blue in the RGB colour model.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifccolourrgb.htm"
    },
    "IfcColourSpecification": {
        "attributes": {
            "Name": "Optional name given to a particular colour specification in addition to the colour components (like the RGB values). >    NOTE  Examples are the names of a industry colour classification, such as RAL."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The colour specification entity contains a direct colour definition. Colour component values refer directly to a specific colour space.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifccolourspecification.htm"
    },
    "IfcColumn": {
        "description": "Definition from ISO 6707-1:1989: Structural member of slender form, usually vertical, that transmits to its base the forces, primarily in compression, that are applied to it.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifccolumn.htm"
    },
    "IfcColumnType": {
        "description": "The element type (IfcColumnType) defines a list of commonly shared property set definitions of a column and an optional set of product representations. It is used to define a column specification (i.e. the specific product information that is common to all occurrences of that product type).",
        "predefined_types": {
            "COLUMN": "A standard member usually vertical and requiring resistance to vertical forces by compression but also sometimes to lateral forces.",
            "NOTDEFINED": "Undefined linear element.",
            "USERDEFINED": "User-defined linear element."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifccolumntype.htm"
    },
    "IfcComplexProperty": {
        "attributes": {
            "HasProperties": "Set of properties that can be used within this complex property (may include other complex properties).",
            "UsageName": "Usage description of the _IfcComplexProperty_ within the property set which references the _IfcComplexProperty_. > NOTE: Consider a complex property for glazing properties. The Name attribute of the IfcComplexProperty could be Pset_GlazingProperties, and the UsageName attribute could be OuterGlazingPane."
        },
        "description": "This IfcComplexProperty is used to define complex properties to be handled completely within a property set. The included list may be a mixed or consistent collection of IfcProperty subtypes. This enables the definition of a list of properties to be included as a single 'property' entry in a property set. The definition of such a list can be reused in many different property sets, but the instantiation of such a complex property shall only be used within a single property set.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifccomplexproperty.htm"
    },
    "IfcCompositeCurve": {
        "attributes": {
            "ClosedCurve": "Indication whether the curve is closed or not; this is derived from the transition code of the last segment. Segments[NSegments].Transition <> Discontinuous",
            "NSegments": "The number of component curves. SIZEOF(Segments)",
            "Segments": "The component bounded curves, their transitions and senses. The transition attribute for the last segment defines the transition between the end of the last segment and the start of the first; this transition attribute may take the value discontinuous, which indicates an open curve.",
            "SelfIntersect": "Indication of whether the curve intersects itself or not; this is for information only."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A composite curve (IfcCompositeCurve) is a collection of curves joined end-to-end. The individual segments of the curve are themselves defined as composite curve segments. The parameterization of the composite curve is an accumulation of the parametric ranges of the referenced bounded curves. The first segment is parameterized from 0 to l~1~~, and, for i\u00b3 2, the i^th^^ segment is parameterized from",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccompositecurve.htm"
    },
    "IfcCompositeCurveSegment": {
        "attributes": {
            "Dim": "The space dimensionality of this class, defined by the dimensionality of the first ParentCurve. ParentCurve.Dim",
            "ParentCurve": "The bounded curve which defines the geometry of the segment.",
            "SameSense": "An indicator of whether or not the sense of the segment agrees with, or opposes, that of the parent curve. If SameSense is false, the point with highest parameter value is taken as the first point of the segment.",
            "Transition": "The state of transition (i.e., geometric continuity from the last point of this segment to the first point of the next segment) in a composite curve.",
            "UsingCurves": "The set of composite curves which use this composite curve segment as a segment. This set shall not be empty."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A composite curve segment (IfcCompositeCurveSegment) is a bounded curve together with transition information which is used to construct a composite curve (IfcCompositeCurve).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccompositecurvesegment.htm"
    },
    "IfcCompositeProfileDef": {
        "attributes": {
            "Label": "The name by which the composition may be referred to. The actual meaning of the name has to be defined in the context of applications.",
            "Profiles": "The profiles which are used to define the composite profile."
        },
        "description": "Definition from IAI: The IfcCompositeProfileDef defines the profile by composition of other profiles. The composition is given by a set of at least two other profile definitions. Any profile definition (except for another composite profile) can be used to construct the composite.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccompositeprofiledef.htm"
    },
    "IfcCompressorType": {
        "description": "The element type IfcCompressorType defines a list of commonly shared property set definitions of a compressor and an optional set of product representations. It is used to define a compressor specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "BOOSTER": "Positive-displacement reciprocating compressor where pressure is increased by a booster.",
            "DYNAMIC": "The pressure of refrigerant vapor is increased by a continuous transfer of angular momentum from a rotating member to the vapor followed by conversion of this momentum into static pressure.",
            "HERMETIC": "Positive-displacement reciprocating compressor where the motor and compressor are contained within the same housing, with the motor shaft integral with the compressor crankshaft and the motor in contact with refrigerant.",
            "NOTDEFINED": "Undefined compressor type.",
            "OPENTYPE": "Positive-displacement reciprocating compressor where the shaft extends through a seal in the crankcase for an external drive.",
            "RECIPROCATING": "Positive-displacement compressor using a piston driven by a connecting rod from a crankshaft.",
            "ROLLINGPISTON": "Positive-displacement rotary compressor using a roller mounted on the eccentric of a shaft with a single vane in the nonrotating cylindrical housing.",
            "ROTARY": "Positive-displacement compressor using a roller or rotor device.",
            "ROTARYVANE": "Positive-displacement rotary compressor using a roller mounted on the eccentric of a shaft with multiple vanes in the nontotating cylindrical housing.",
            "SCROLL": "Positive-displacement compressor using two inter-fitting, spiral-shaped scroll members.",
            "SEMIHERMETIC": "Positive-displacement reciprocating compressor where the hermetic compressors use bolted construction amenable to field repair.",
            "SINGLESCREW": "Positive-displacement rotary compressor using a single cylindrical main rotor that works with a pair of gate rotors.",
            "SINGLESTAGE": "Positive-displacement reciprocating compressor where vapor is compressed in a single stage.",
            "TROCHOIDAL": "Positive-displacement compressor using a rolling motion of one circle outside or inside the circumference of a basic circle and produce either epitrochoids or hypotrochoids.",
            "TWINSCREW": "Positive-displacement rotary compressor using two mating helically grooved rotors, male (lobes) and female (flutes) in a stationary housing with inlet and outlet gas ports.",
            "USERDEFINED": "User-defined compressor type.",
            "WELDEDSHELLHERMETIC": "Positive-displacement reciprocating compressor where the motor compressor is mounted inside a steel shell, which, in turn is sealed by welding."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccompressortype.htm"
    },
    "IfcCondenserType": {
        "description": "The element type IfcCondenserType defines a list of commonly shared property set definitions of a condenser and an optional set of product representations. It is used to define a condenser specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "AIRCOOLED": "A condenser in which heat is transferred to an air-stream.",
            "EVAPORATIVECOOLED": "A condenser that is cooled evaporatively.",
            "NOTDEFINED": "Undefined condenser type.",
            "USERDEFINED": "User-defined condenser type.",
            "WATERCOOLEDBRAZEDPLATE": "Water-cooled condenser with plates brazed together to form an assembly of separate channels.",
            "WATERCOOLEDSHELLCOIL": "Water-cooled condenser with cooling water circulated through one or more continuous or assembled coils contained within the shell.",
            "WATERCOOLEDSHELLTUBE": "Water-cooled condenser with cooling water circulated through one or more tubes contained within the shell.",
            "WATERCOOLEDTUBEINTUBE": "Water-cooled condenser consisting of one or more assemblies of two tubes, one within the other."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccondensertype.htm"
    },
    "IfcCondition": {
        "description": "An IfcCondition determines the state or condition of an element at a particular point in time",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifccondition.htm"
    },
    "IfcConditionCriterion": {
        "attributes": {
            "Criterion": "The measured or assessed value of a criterion.",
            "CriterionDateTime": "The time and/or date at which the criterion is determined."
        },
        "description": "An IfcConditionCriterion is a particular measured or assessed criterion that contributes to the overall condition of an artifact.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcconditioncriterion.htm"
    },
    "IfcConic": {
        "attributes": {
            "Position": "The location and orientation of the conic. Further details of the interpretation of this attribute are given for the individual subtypes.\""
        },
        "description": "Definition from ISO/CD 10303-42:1992: A conic (IfcConic) is a planar curve which could be produced by intersecting a plane with a cone. A conic is defined in terms of its intrinsic geometric properties rather than being described in terms of other geometry. A conic class always has a placement coordinate system defined by a two or three dimensional placement. The parametric representation is defined in terms of this placement coordinate system.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcconic.htm"
    },
    "IfcConnectedFaceSet": {
        "attributes": {
            "CfsFaces": "The set of faces arcwise connected along common edges or vertices."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A connected_face_set is a set of faces such that the domain of faces together with their bounding edges and vertices is connected.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcconnectedfaceset.htm"
    },
    "IfcConnectionCurveGeometry": {
        "attributes": {
            "CurveOnRelatedElement": "The bounded curve at which the connected objects are aligned at the related element, given in the LCS of the related element. If the information is omitted, then the origin of the related element is used.",
            "CurveOnRelatingElement": "The bounded curve at which the connected objects are aligned at the relating element, given in the LCS of the relating element."
        },
        "description": "The IfcConnectionCurveGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a curve or at an edge with curve geometry associated. It is envisioned as a control that applies to the element connection relationships.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectioncurvegeometry.htm"
    },
    "IfcConnectionGeometry": {
        "description": "The IfcConnectionGeometry is used to describe the geometric and topological constraints that facilitate the physical connection of two objects. It is envisioned as a control that applies to the element connection relationships.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectiongeometry.htm"
    },
    "IfcConnectionPointEccentricity": {
        "attributes": {
            "EccentricityInX": "Distance in x direction between the two points (or vertex points) engaged in the point connection.",
            "EccentricityInY": "Distance in y direction between the two points (or vertex points) engaged in the point connection.",
            "EccentricityInZ": "Distance in z direction between the two points (or vertex points) engaged in the point connection."
        },
        "description": "The IfcConnectionPointEccentricity is used to describe the geometric constraints that facilitate the physical connection of two objects at a point or vertex point with associated point coordinates. There is a physical distance, or eccentricity, between the connection points of both object. The eccentricity can be either given by:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectionpointeccentricity.htm"
    },
    "IfcConnectionPointGeometry": {
        "attributes": {
            "PointOnRelatedElement": "Point at which connected objects are aligned at the related element, given in the LCS of the related element. If the information is omitted, then the origin of the related element is used.",
            "PointOnRelatingElement": "Point at which the connected object is aligned at the relating element, given in the LCS of the relating element."
        },
        "description": "The IfcConnectionPointGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a point (here IfcCartesianPoint) or at an vertex with point coordinates associated. It is envisioned as a control that applies to the element connection relationships.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectionpointgeometry.htm"
    },
    "IfcConnectionPortGeometry": {
        "attributes": {
            "LocationAtRelatedElement": "Local placement of the port relative to its distribution element's local placement. The element in question is that, which plays the role of the related element in the connectivity relationship.",
            "LocationAtRelatingElement": "Local placement of the port relative to its distribution element's local placement. The element in question is that, which plays the role of the relating element in the connectivity relationship.",
            "ProfileOfPort": "Profile that defines the port connection geometry. It is placed inside the XY plane of the location, given at the relating and (optionally) related distribution element."
        },
        "description": "The IfcConnectionPortGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a port having a profile geometry (here IfcProfile). It is envisioned as a control that applies to the element connection relationships.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectionportgeometry.htm"
    },
    "IfcConnectionSurfaceGeometry": {
        "attributes": {
            "SurfaceOnRelatedElement": "Surface at which the relating element is aligned at the related element, given in the LCS of the related element. If the information is omitted, then the origin of the related element is used.",
            "SurfaceOnRelatingElement": "Surface at which related object is aligned at the relating element, given in the LCS of the relating element."
        },
        "description": "The IfcConnectionSurfaceGeometry is used to describe the geometric constraints that facilitate the physical connection of two objects at a surface or at a face with surface geometry associated. It is envisioned as a control that applies to the element connection relationships.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcconnectionsurfacegeometry.htm"
    },
    "IfcConstraint": {
        "attributes": {
            "Aggregates": "Reference to the relationships that collect other constraints into this aggregate constraint.",
            "ClassifiedAs": "Reference to the constraint classifications through objectified relationship.",
            "ConstraintGrade": "Enumeration that qualifies the type of constraint.",
            "ConstraintSource": "Any source material, such as a code or standard, from which the constraint originated.",
            "CreatingActor": "Person and/or organization that has created the constraint.",
            "CreationTime": "Time when information specifying the constraint instance was created.",
            "Description": "A description that may apply additional information about a constraint.",
            "IsAggregatedIn": "Reference to the relationships that relate this constraint into aggregate constraints.",
            "IsRelatedWith": "References to the objectified relationships that relate this constraint with other constraints.",
            "Name": "A name to be used for the constraint (e.g., ChillerCoefficientOfPerformance).",
            "PropertiesForConstraint": "Reference to the properties to which the constraint is applied.",
            "RelatesConstraints": "References to the objectified relationships that relate other constraints with this constraint.",
            "UserDefinedGrade": "Allows for specification of user defined grade of the constraint  beyond the enumeration values (hard, soft, advisory) provided by ConstraintGrade attribute of type _IfcConstraintEnum_.  When a value is provided for attribute UserDefinedGrade in parallel the attribute ConstraintGrade shall have enumeration value USERDEFINED."
        },
        "description": "An IfcConstraint is used to define a constraint or limiting value or boundary condition that may be applied to an object or to the value of a property.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcconstraint.htm"
    },
    "IfcConstraintAggregationRelationship": {
        "attributes": {
            "Description": "A description that may apply additional information about a constraint aggregation.",
            "LogicalAggregator": "Enumeration that identifies the logical type of aggregation.",
            "Name": "A name used to identify or qualify the constraint aggregation.",
            "RelatedConstraints": "Constraints that are aggregated in using the LogicalAggregator.",
            "RelatingConstraint": "Constraint to which the other Constraints are associated."
        },
        "description": "An IfcConstraintAggregationRelationship is an objectified relationship that enables instances of IfcConstraint and its subtypes to be aggregated together logically.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcconstraintaggregationrelationship.htm"
    },
    "IfcConstraintClassificationRelationship": {
        "attributes": {
            "ClassifiedConstraint": "Constraint being classified",
            "RelatedClassifications": "Classifications of the constraint."
        },
        "description": "An IfcClassificationConstraintRelationship is an objectified relationship that enables assigning classifications to instances of IfcConstraint and its subtypes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcconstraintclassificationrelationship.htm"
    },
    "IfcConstraintRelationship": {
        "attributes": {
            "Description": "A description that may apply additional information about the constraint relationship.",
            "Name": "A name used to identify or qualify the constraint relationship.",
            "RelatedConstraints": "Constraints that are related with the RelatingConstraint.",
            "RelatingConstraint": "Constraint with which the other Constraints referenced by attribute RelatedConstraints are related."
        },
        "description": "An IfcConstraintRelationship is an objectified relationship that enables instances of IfcConstraint and its subtypes to be associated to each other.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcconstraintrelationship.htm"
    },
    "IfcConstructionEquipmentResource": {
        "description": "An IfcConstructionEquipmentResource is a type of construction equipment that is used as resource to assist in the performance of construction. Construction Equipment resources are wholly or partially consumed, or occupied (i.e. used) in the performance of construction.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifcconstructionequipmentresource.htm"
    },
    "IfcConstructionMaterialResource": {
        "attributes": {
            "Suppliers": "Possible suppliers of the type of materials.",
            "UsageRatio": "The ratio of the amount of a construction material used to the amount provided (determined as a quantity)"
        },
        "description": "An IfcConstructionMaterialResource identifies a material resource type in a construction project.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifcconstructionmaterialresource.htm"
    },
    "IfcConstructionProductResource": {
        "description": "An IfcConstructionProductResource defines the role of a product that is consumed (wholly or partially), or occupied (i.e. used) in the performance of construction.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifcconstructionproductresource.htm"
    },
    "IfcConstructionResource": {
        "attributes": {
            "BaseQuantity": "The basic (i.e. default, or recommended) unit that should be used for measuring the volume (or amount) of the resource and the basic quantity of the resource fully or partially consumed.",
            "ResourceConsumption": "A value that indicates how the resource is consumed during its use in a process (see _IfcResourceConsumptionEnum_ for more detail)",
            "ResourceGroup": "The group label, or title of the type resource, e.g. the title of a labour resource as carpenter, crane operator, superintendent, etc.",
            "ResourceIdentifier": "Optional identification of a code or ID for the construction resource"
        },
        "description": "An IfcConstructionResource is an abstract generalization of the different resources used in construction projects, mainly labor, material, equipment and product resources, plus subcontracted resources and aggregations, such as a crew resource.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifcconstructionresource.htm"
    },
    "IfcContextDependentUnit": {
        "attributes": {
            "Name": "The word, or group of words, by which the context dependent unit is referred to."
        },
        "description": "Definition from ISO/CD 10303-41:1992: A context dependent unit is a unit which is not related to the SI system.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifccontextdependentunit.htm"
    },
    "IfcControl": {
        "attributes": {
            "Controls": "Reference to the relationship that associates the control to the object(s) being controlled."
        },
        "description": "The IfcControl is the abstract generalization of all concepts that control or constrain products or processes in general. It can be seen as a specification, regulation, cost schedule or other requirement applied to a product or process whose requirements and provisions must be fulfilled. Controls are assigned to products, processes, or other objects by using the IfcRelAssignsToControl relationship.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifccontrol.htm"
    },
    "IfcControllerType": {
        "description": "An IfcControllerType defines a particular type of controller that interacts with other devices in a control system such as a building automation control system.",
        "predefined_types": {
            "FLOATING": "Output increases or decreases at a constant or accelerating rate.",
            "NOTDEFINED": "Undefined type.",
            "PROPORTIONAL": "Output is proportional to the control error and optionally time integral and derivative.",
            "PROPORTIONALINTEGRAL": "",
            "PROPORTIONALINTEGRALDERIVATIVE": "",
            "TIMEDTWOPOSITION": "",
            "TWOPOSITION": "Output can be either on or off.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifccontrollertype.htm"
    },
    "IfcConversionBasedUnit": {
        "attributes": {
            "ConversionFactor": "The physical quantity from which the converted unit is derived.",
            "Name": "The word, or group of words, by which the conversion based unit is referred to."
        },
        "description": "Definition from ISO/CD 10303-41:1992: A conversion based unit is a unit that is defined based on a measure with unit.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcconversionbasedunit.htm"
    },
    "IfcCooledBeamType": {
        "description": "The element type IfcCooledBeamType defines a list of commonly shared property set definitions of a cooled beam and an optional set of product representations. It is used to define a cooled beam specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "ACTIVE": "An active or ventilated cooled beam provides cooling (and heating) but can also function as an air terminal in a ventilation system.",
            "NOTDEFINED": "Undefined cooled beam type.",
            "PASSIVE": "A passive or static cooled beam provides cooling (and heating) to a room or zone.",
            "USERDEFINED": "User-defined cooled beam type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccooledbeamtype.htm"
    },
    "IfcCoolingTowerType": {
        "description": "The element type IfcCoolingTowerType defines a list of commonly shared property set definitions of a cooling tower and an optional set of product representations. It is used to define a cooling tower specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "MECHANICALFORCEDDRAFT": "Air flow is produced by a mechanical device, typically one or more fans, located on the inlet air side of the cooling tower.",
            "MECHANICALINDUCEDDRAFT": "Air flow is produced by a mechanical device, typically one or more fans, located on the air outlet side of the cooling tower.",
            "NATURALDRAFT": "Air flow is produced naturally.",
            "NOTDEFINED": "Undefined cooling tower type.",
            "USERDEFINED": "User-defined cooling tower type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifccoolingtowertype.htm"
    },
    "IfcCoordinatedUniversalTimeOffset": {
        "attributes": {
            "HourOffset": "The number of hours by which local time is offset from coordinated universal time.",
            "MinuteOffset": "The number of minutes by which local time is offset from coordinated universal time.",
            "Sense": "The direction of the offset.   > Note: The data type of the Sense is an enumeration - AHEAD means positive offset;  BEHIND means negative offset."
        },
        "description": "Definition from ISO/CD 10303-41:1992: Relates a time to coordinated universal time by an offset (specified in hours and minutes) and direction.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifccoordinateduniversaltimeoffset.htm"
    },
    "IfcCostItem": {
        "description": "An IfcCostItem describes a cost or financial value together with descriptive information that describes its context in a form that enables it to be used within a cost schedule.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifccostitem.htm"
    },
    "IfcCostSchedule": {
        "attributes": {
            "ID": "A unique identification assigned to a cost schedule that enables its differentiation from other cost schedules.",
            "PreparedBy": "The identity of the person or organization preparing the cost schedule.",
            "Status": "The current status of a cost schedule. Examples of status values that might be used for a cost schedule status include: - PLANNED - APPROVED - AGREED - ISSUED - STARTED",
            "SubmittedBy": "The identity of the person or organization submitting the cost schedule.",
            "SubmittedOn": "The date on which the cost schedule was submitted.",
            "TargetUsers": "The actors for whom the cost schedule was prepared.",
            "UpdateDate": "The date that this cost schedule is updated; this allows tracking the schedule history."
        },
        "description": "An IfcCostSchedule brings together instances of IfcCostItem either for the purpose of identifying purely cost information as in an estimate for constructions costs, bill of quantities etc. or for including cost information within another presentation form such as an order (of whatever type)",
        "predefined_types": {
            "BUDGET": "An allocation of money for a particular purpose.",
            "COSTPLAN": "An assessment of the amount of money needing to be expended for a defined purpose based on incomplete information about the goods and services required for a construction or installation.",
            "ESTIMATE": "An assessment of the amount of money needing to be expended for a defined purpose based on actual information about the goods and services required for a construction or installation.",
            "NOTDEFINED": "Undefined type.",
            "PRICEDBILLOFQUANTITIES": "A complete listing of all work items forming construction or installation works in which costs have been allocated to work items.",
            "SCHEDULEOFRATES": "A listing of each type of goods forming construction or installation works with the cost of purchase, construction/installation, overheads and profit assigned so that additional items of that type can be costed.",
            "TENDER": "An offer to provide goods and services.",
            "UNPRICEDBILLOFQUANTITIES": "A complete listing of all work items forming construction or installation works in which costs have not yet been allocated to work items.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifccostschedule.htm"
    },
    "IfcCostValue": {
        "attributes": {
            "Condition": "The condition under which a cost value applies.",
            "CostType": "Specification of the type of cost type used.  > NOTE: There are many possible types of cost value that may be identified. Whilst there is a broad understanding of the meaning of names that may be assigned to different types of costs, there is no general standard for naming cost types nor are there any broadly defined classifications. To allow for any type of cost value, the IfcLabel datatype is assigned.     In the absence of any well defined standard, it is recommended that local agreements should be made to define allowable and understandable cost value types within a project or region."
        },
        "description": "An IfcCostValue is an amount of money or a value that affects an amount of money.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifccostvalue.htm"
    },
    "IfcCovering": {
        "attributes": {
            "Covers": "Reference to the objectified relationship that handles the relationship of the covering to the covered space.",
            "CoversSpaces": ""
        },
        "description": "Definition from ISO 6707-1:1989: term used: Finishing - final coverings and treatments of surfaces and their intersections.",
        "predefined_types": {
            "CEILING": "The covering is used torepresent a ceiling.",
            "CLADDING": "The covering is used to represent a cladding.",
            "FLOORING": "The covering is used to represent a flooring.",
            "INSULATION": "The covering is used to insulate an element for thermal or acoustic purposes.",
            "MEMBRANE": "An impervious layer that could be used for e.g. roof covering (below tiling - that may be known as sarking etc.) or as a damp proof course membrane.",
            "NOTDEFINED": "Undefined type of covering.",
            "ROOFING": "The covering is used to represent a roof covering.",
            "SLEEVING": "The covering is used to isolate a distribution element from a space in which it is contained.",
            "USERDEFINED": "User defined type of covering.",
            "WRAPPING": "The covering is used for wrapping particularly of distribution elements using tape."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifccovering.htm"
    },
    "IfcCoveringType": {
        "description": "The IfcCoveringType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "CEILING": "The covering is used torepresent a ceiling.",
            "CLADDING": "The covering is used to represent a cladding.",
            "FLOORING": "The covering is used to represent a flooring.",
            "INSULATION": "The covering is used to insulate an element for thermal or acoustic purposes.",
            "MEMBRANE": "An impervious layer that could be used for e.g. roof covering (below tiling - that may be known as sarking etc.) or as a damp proof course membrane.",
            "NOTDEFINED": "Undefined type of covering.",
            "ROOFING": "The covering is used to represent a roof covering.",
            "SLEEVING": "The covering is used to isolate a distribution element from a space in which it is contained.",
            "USERDEFINED": "User defined type of covering.",
            "WRAPPING": "The covering is used for wrapping particularly of distribution elements using tape."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifccoveringtype.htm"
    },
    "IfcCraneRailAShapeProfileDef": {
        "attributes": {
            "BaseDepth1": "Base depth of the A shape crane rail, see illustration above (= s1).",
            "BaseDepth2": "Base depth of the A shape crane rail, see illustration above (= s2).",
            "BaseDepth3": "Depth of the base where thickness changes, see illustration above (= s3).",
            "BaseWidth2": "Total extent of the width of the base, defined parallel to the x axis of the position coordinate system. See illustration above (= b2).",
            "BaseWidth4": "Width of the base where thickness changes, defined parallel to the x axis of the position coordinate system. See illustration above (= b4).",
            "CentreOfGravityInY": "Location of centre of gravity along the y axis measured from the center of the bounding box.",
            "HeadDepth2": "Head depth of the A shape crane rail, see illustration above (= h2).",
            "HeadDepth3": "Head depth of the A shape crane rail, see illustration above (= h3).",
            "HeadWidth": "Total extent of the width of the head, defined parallel to the x axis of the position coordinate system. See illustration above (= b1).",
            "OverallHeight": "Total extent of the height, defined parallel to the y axis of the position coordinate system. See illustration above (= h1).",
            "Radius": "Edge radius according the above illustration (= r1).",
            "WebThickness": "Thickness of the web of the A shape crane rail. See illustration above (= b3)."
        },
        "description": "Definition from IAI: The IfcCraneRailAShapeProfileDef defines a section profile that provides the defining parameters of a crane rail to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccranerailashapeprofiledef.htm"
    },
    "IfcCraneRailFShapeProfileDef": {
        "attributes": {
            "BaseDepth1": "Base depth of the F shape crane rail, see illustration above (= s1).",
            "BaseDepth2": "Base depth of the F shape crane rail, see illustration above (= s2).",
            "CentreOfGravityInY": "Location of centre of gravity along the y axis measured from the center of the bounding box.",
            "HeadDepth2": "Head depth of the F shape crane rail, see illustration above (= h2).",
            "HeadDepth3": "Head depth of the F shape crane rail, see illustration above (= h3).",
            "HeadWidth": "Total extent of the width of the head, defined parallel to the x axis of the position coordinate system. See illustration above (= k)",
            "OverallHeight": "Total extent of the height, defined parallel to the y axis of the position coordinate system. See illustration above (= h1).",
            "Radius": "Edge radius according the above illustration (= r1).",
            "WebThickness": "Thickness of the web of the F shape crane rail. See illustration above (= b3)"
        },
        "description": "Definition from IAI: The IfcCraneRailFShapeProfileDef defines a section profile that provides the defining parameters of a crane rail to be used by the swept surface geometry or the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifccranerailfshapeprofiledef.htm"
    },
    "IfcCrewResource": {
        "description": "An IfcCrewResource represents a type of resource used in construction processes, i.e. construction crew resource.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifccrewresource.htm"
    },
    "IfcCsgPrimitive3D": {
        "attributes": {
            "Dim": "The space dimensionality of this geometric representation item, it is always 3. 3",
            "Position": "The placement coordinate system to which the parameters of each individual CSG primitive apply."
        },
        "description": "Definition from IAI:  Abstract supertype of all three dimensional primitives used as either tree root item, or as Boolean results within an CSG solid model. All 3D CSG primitives are defined within an three-dimensional placement coordinate system,.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifccsgprimitive3d.htm"
    },
    "IfcCsgSolid": {
        "attributes": {
            "TreeRootExpression": "Boolean expression of regularized operators describing the solid. The root of the tree of Boolean expressions is given explicitly as an IfcBooleanResult (the only item in the Select IfcCsgSelect)."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A solid represented as a CSG model is defined by a collection of so-called primitive solids, combined using regularized Boolean operations. The allowed operations are intersection, union, and difference. As a special case a CSG solid can also consists of a single CSG primitive.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifccsgsolid.htm"
    },
    "IfcCurrencyRelationship": {
        "attributes": {
            "ExchangeRate": "The currently agreed ratio of the amount of a related monetary unit that is equivalent to a unit amount of the relating monetary unit in a currency relationship. For instance, in the case of a conversion from GBP to USD, the value of the exchange rate may be 1.486 (USD) : 1 (GBP).",
            "RateDateTime": "The date and time at which an exchange rate applies.",
            "RateSource": "The source from which an exchange rate is obtained.",
            "RelatedMonetaryUnit": "The monetary unit to which an exchange results. For instance, in the case of a conversion from GBP to USD, the related monetary unit is USD.",
            "RelatingMonetaryUnit": "The monetary unit from which an exchange is derived. For instance, in the case of a conversion from GBP to USD, the relating monetary unit is GBP."
        },
        "description": "An IfcCurrencyRelationship defines the rate of exchange that applies between two designated currencies at a particular time and as published by a particular source.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifccurrencyrelationship.htm"
    },
    "IfcCurtainWall": {
        "description": "Definition from ISO 6707-1:1989: Non load bearing wall positioned on the outside of a building and enclosing it.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifccurtainwall.htm"
    },
    "IfcCurtainWallType": {
        "description": "The element type (IfcCurtainWallType) defines a list of commonly shared property set definitions of a curtain wall element and an optional set of product representations. It is used to define a curtain wall specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "NOTDEFINED": "",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifccurtainwalltype.htm"
    },
    "IfcCurve": {
        "attributes": {
            "Dim": "The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve. IfcCurveDim(SELF)"
        },
        "description": "Definition from ISO/CD 10303-42:1992: A curve can be envisioned as the path of a point moving in its coordinate space.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccurve.htm"
    },
    "IfcCurveBoundedPlane": {
        "attributes": {
            "BasisSurface": "The surface to be bound.",
            "Dim": "The space dimensionality of this class, defined by the dimensionality of the basis surface. BasisSurface.Dim",
            "InnerBoundaries": "An optional set of inner boundaries. They shall not intersect each other or the outer boundary.",
            "OuterBoundary": "The outer boundary of the surface."
        },
        "description": "Definition from ISO/CD 10303-42:1992: The curve bounded surface is a parametric surface with curved boundaries defined by one or more boundary curves. The bounded surface is defined to be the portion of the basis surface in the direction of N x T from any point on the boundary, where N is the surface normal and T the boundary curve tangent vector at this point. The region so defined shall be arcwise connected.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifccurveboundedplane.htm"
    },
    "IfcCurveStyle": {
        "attributes": {
            "CurveColour": "The colour of the visible part of the curve. If not given, then the colour should be taken from the layer assignment with style, if that is not given either, then the default colour applies.",
            "CurveFont": "A curve style font which is used to present a curve. It can either be a predefined curve font, or an explicitly defined curve font. Both may be scaled. If not given, then the curve font should be taken from the layer assignment with style, if that is not given either, then the default curve font applies.",
            "CurveWidth": "A positive length measure in units of the presentation area for the width of a presented curve. If not given, then the style should be taken from the layer assignment with style, if that is not given either, then the default style applies."
        },
        "description": "Definition from ISO/CD 10303-46:1992: A curve style specifies the visual appearance of curves.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifccurvestyle.htm"
    },
    "IfcCurveStyleFont": {
        "attributes": {
            "Name": "Name that may be assigned with the curve font.",
            "PatternList": "A list of curve font pattern entities, that contains the simple patterns used for drawing curves. The patterns are applied in the order they occur in the list."
        },
        "description": "Definition from ISO/CD 10303-46:1992: A curve style font combines several curve style font pattern entities into a more complex pattern. The resulting pattern is repeated along the curve.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifccurvestylefont.htm"
    },
    "IfcCurveStyleFontAndScaling": {
        "attributes": {
            "CurveFont": "The curve font to be scaled.",
            "CurveFontScaling": "The scale factor.",
            "Name": "Name that may be assigned with the scaling of a curve font."
        },
        "description": "Definition from ISO/CD 10303-46:1992: A curve style font and scaling is a curve style font and a scalar factor for that font, so that a given curve style font may be applied at various scales.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifccurvestylefontandscaling.htm"
    },
    "IfcCurveStyleFontPattern": {
        "attributes": {
            "InvisibleSegmentLength": "The length of the invisible segment in the pattern definition.",
            "VisibleSegmentLength": "The length of the visible segment in the pattern definition. >    NOTE  For a visible segment representing a point, the value 0. should be assigned."
        },
        "description": "Definition from ISO/CD 10303-46:1992: A curve style font pattern is a pair of visible and invisible curve segment length measures in presentation area units.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifccurvestylefontpattern.htm"
    },
    "IfcDamperType": {
        "description": "The element type IfcDamperType defines a list of commonly shared property set definitions of a damper and an optional set of product representations. It is used to define a damper specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "BACKDRAFTDAMPER": "Damper used for purposes of manually balancing pressure differences.  Commonly operated by mechanical adjustment.",
            "BALANCINGDAMPER": "Backdraft damper used to restrict the movement of air in one direction.  Commonly operated by mechanical spring.",
            "BLASTDAMPER": "Blast damper used to prevent protect occupants and equipment against overpressures resultant of an explosion.  Commonly operated by mechanical spring.",
            "CONTROLDAMPER": "Control damper used to modulate the flow of air by adjusting the position of the blades.  Commonly operated by an actuator of a building automation system.",
            "FIREDAMPER": "Fire damper used to prevent the spread of fire for a specified duration.  Commonly operated by fusable link that melts above a certain temperature.",
            "FIRESMOKEDAMPER": "Combination fire and smoke damper used to preven the spread of fire and smoke.  Commonly operated by a fusable link and a smoke detector.",
            "FUMEHOODEXHAUST": "Fume hood exhaust damper.  Commonly operated by actuator.",
            "GRAVITYDAMPER": "Gravity damper closes from the force of gravity.  Commonly operated by gravitational weight.",
            "GRAVITYRELIEFDAMPER": "Gravity-relief damper used to allow air to move upon a buildup of enough pressure to overcome the gravitational force exerted upon the damper blades.  Commonly operated by gravitational weight.",
            "NOTDEFINED": "Undefined damper.",
            "RELIEFDAMPER": "Relief damper used to allow air to move upon a buildup of a specified pressure differential.  Commonly operated by mechanical spring.",
            "SMOKEDAMPER": "Smoke damper used to prevent the spread of smoke.  Commonly operated by a smoke detector of a building automation system.",
            "USERDEFINED": "User-defined damper."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcdampertype.htm"
    },
    "IfcDateAndTime": {
        "attributes": {
            "DateComponent": "The date element of the date time combination.",
            "TimeComponent": "The time element of the date time combination."
        },
        "description": "Definition from ISO/CD 10303-41:1992: A moment of time on a particular day.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifcdateandtime.htm"
    },
    "IfcDefinedSymbol": {
        "attributes": {
            "Definition": "An implicit description of the symbol, either predefined or externally defined.",
            "Target": "A description of the placement, orientation and (uniform or non-uniform) scaling of the defined symbol."
        },
        "description": "A defined symbol is a symbolic representation that gets its shape information by an established convention, either through a predefined symbol, or an externally defined symbol.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcdefinedsymbol.htm"
    },
    "IfcDerivedProfileDef": {
        "attributes": {
            "Label": "The name by which the transformation may be referred to. The actual meaning of the name has to be defined in the context of applications.",
            "Operator": "Transformation operator applied to the parent profile.",
            "ParentProfile": "The parent profile provides the origin of the transformation."
        },
        "description": "Definition from IAI: The IfcDerivedProfileDef defines the profile by transformation from the parent profile. The transformation is given by a two dimensional transformation operator. Transformation includes translation, rotation, mirror and scaling. The latter can be uniform or non uniform. The derived profiles may be used to define swept surfaces, swept area solids or sectioned spines.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcderivedprofiledef.htm"
    },
    "IfcDerivedUnit": {
        "attributes": {
            "Dimensions": "Dimensional exponents derived using the function IfcDerivedDimensionalExponents using (SELF) as the input value. IfcDeriveDimensionalExponents(Elements)",
            "Elements": "The group of units and their exponents that define the derived unit.",
            "UnitType": "Name of the derived unit chosen from an enumeration of derived unit types for use in IFC models.",
            "UserDefinedType": ""
        },
        "description": "Definition from ISO/CD 10303-41:1992: A derived unit is an expression of units.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcderivedunit.htm"
    },
    "IfcDerivedUnitElement": {
        "attributes": {
            "Exponent": "The power that is applied to the unit attribute.",
            "Unit": "The fixed quantity which is used as the mathematical factor."
        },
        "description": "Definition from ISO/CD 10303-41:1992: A derived unit element is one of the unit quantities which makes up a derived unit.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcderivedunitelement.htm"
    },
    "IfcDiameterDimension": {
        "description": "The diameter dimension is a draughting callout that presents the diameter extent of a conic element. It consists of a dimension curve and may have projection curves (but is often defined without projection curves).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdiameterdimension.htm"
    },
    "IfcDimensionCalloutRelationship": {
        "description": "A dimension callout relationship is a relationship between two draughting callouts. The relating draughting callout refers to a dimension (linear, diameter, radius, or angular) while the related draughting callout refers to the dimension text (as structured dimension callout). This structured dimension callout can either be denoted as \"primary\", in which case it presents the dimension value in the primary unit, or as \"secondary\", in which case it presents the dimension value in the secondary unit.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdimensioncalloutrelationship.htm"
    },
    "IfcDimensionCurve": {
        "attributes": {
            "AnnotatedBySymbols": "Reference to the terminator symbols that may be assigned to the dimension curve. There shall be either zero, one or two terminator symbols assigned."
        },
        "description": "A dimension curve is an annotated curve within a dimension that has the dimension text and may have terminator symbols assigned. It is used to present the extent and the direction of the dimension.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdimensioncurve.htm"
    },
    "IfcDimensionCurveDirectedCallout": {
        "description": "The dimension curve directed callout is a dimension callout, which includes a dimension line. It normally presents an extent and/or direction of the product shape. Subtypes are introduced to declare specific forms of dimension curve directed callouts, such as:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdimensioncurvedirectedcallout.htm"
    },
    "IfcDimensionCurveTerminator": {
        "attributes": {
            "Role": "Role of the dimension curve terminator within a dimension curve (being either an origin or target)."
        },
        "description": "A dimension curve terminator is an annotated symbol, which is used at a dimension curve. It normally indicates the origin or target of the dimension curve.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdimensioncurveterminator.htm"
    },
    "IfcDimensionPair": {
        "description": "A dimension pair relationship is a relationship between two draughting callouts. The relating draughting callout refers to a dimension (linear, diameter, radius, or angular) and the related draughting callout refers to another dimension (linear, diameter, radius, or angular). This structured dimension callout can either be denoted as \"chained\", in which case the related dimension continues from the end of the relating dimension, or as \"parallel\", in which case the related dimension starts again from the start of the relating dimension.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdimensionpair.htm"
    },
    "IfcDimensionalExponents": {
        "attributes": {
            "AmountOfSubstanceExponent": "The power of the amount of substance base quantity.",
            "ElectricCurrentExponent": "The power of the electric current base quantity.",
            "LengthExponent": "The power of the length base quantity.",
            "LuminousIntensityExponent": "The power of the luminous intensity base quantity.",
            "MassExponent": "The power of the mass base quantity.",
            "ThermodynamicTemperatureExponent": "The power of the thermodynamic temperature base quantity.",
            "TimeExponent": "The power of the time base quantity."
        },
        "description": "Definition from ISO/CD 10303-41:1992: The dimensionality of any quantity can be expressed as a product of powers of the dimensions of base quantities. The dimensional exponents entity defines the powers of the dimensions of the base quantities. All the physical quantities are founded on seven base quantities (ISO 31 (clause 2)).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcdimensionalexponents.htm"
    },
    "IfcDirection": {
        "attributes": {
            "Dim": "The space dimensionality of this class, defined by the number of real in the list of DirectionRatios. HIINDEX(DirectionRatios)",
            "DirectionRatios": "The components in the direction of X axis (DirectionRatios[1]), of Y axis (DirectionRatios[2]), and of Z axis (DirectionRatios[3])"
        },
        "description": "Definition from ISO/CD 10303-42:1992: This entity defines a general direction vector in two or three dimensional space. The actual magnitudes of the components have no effect upon the direction being defined, only the ratios X:Y:Z or X:Y are significant.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcdirection.htm"
    },
    "IfcDiscreteAccessory": {
        "description": "Representation of different kinds of accessories included in or added to elements.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcdiscreteaccessory.htm"
    },
    "IfcDiscreteAccessoryType": {
        "description": "The element type (IfcDiscreteAccessoryType) defines a list of commonly shared property set definitions of a discrete accessory and an optional set of product representations. It is used to define a supporting element mainly within structural and building services domains (i.e. the specific type information common to all occurrences of that type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcdiscreteaccessorytype.htm"
    },
    "IfcDistributionChamberElement": {
        "description": "The IfcDistributionChamberElement defines a place at which distribution systems and their constituent elements may be inspected or through which they may travel.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributionchamberelement.htm"
    },
    "IfcDistributionChamberElementType": {
        "description": "The element type IfcDistributionChamberElementType defines a list of commonly shared property set definitions of a distribution chamber element and an optional set of product representations. It is used to define a distribution chamber element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "FORMEDDUCT": "Space formed in the ground for the passage of pipes, cables, ducts.",
            "INSPECTIONCHAMBER": "Chamber constructed on a drain, sewer or pipeline with a removable cover that permits visble inspection.",
            "INSPECTIONPIT": "Recess or chamber formed to permit access for inspection of substructure and services.",
            "MANHOLE": "hamber constructed on a drain, sewer or pipeline with a removable cover that permits the entry of a person.",
            "METERCHAMBER": "Chamber that houses a meter(s).",
            "NOTDEFINED": "Undefined chamber type.",
            "SUMP": "Recessed or small chamber into which liquid is drained to facilitate its collection for removal.",
            "TRENCH": "Excavated chamber, the length of which typically exceeds the width.",
            "USERDEFINED": "User-defined chamber type.",
            "VALVECHAMBER": "Chamber that houses a valve(s)."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributionchamberelementtype.htm"
    },
    "IfcDistributionControlElement": {
        "attributes": {
            "AssignedToFlowElement": "Reference through the relationship object to related distribution flow elements.",
            "ControlElementId": "The ControlElement Point Identification assigned to this control element by the Building Automation System."
        },
        "description": "The distribution element IfcDistributionControlElement defines occurrence elements of a building automation control system that are used to impart control over elements of a distribution system.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributioncontrolelement.htm"
    },
    "IfcDistributionControlElementType": {
        "description": "The element type IfcDistributionControlElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributioncontrolelementtype.htm"
    },
    "IfcDistributionElement": {
        "description": "Generalization of all elements that participate in a distribution system. Typical examples of IfcDistributionElement are (among others):",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcdistributionelement.htm"
    },
    "IfcDistributionElementType": {
        "description": "The IfcDistributionElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcdistributionelementtype.htm"
    },
    "IfcDistributionFlowElement": {
        "attributes": {
            "HasControlElements": "Reference to the relationship object that relates control elements."
        },
        "description": "The distribution element IfcDistributionFlowElement defines occurrence elements of a distribution system that facilitate the distribution of energy or matter, such as air, water or power.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributionflowelement.htm"
    },
    "IfcDistributionFlowElementType": {
        "description": "The element type IfcDistributionFlowElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributionflowelementtype.htm"
    },
    "IfcDistributionPort": {
        "attributes": {
            "FlowDirection": "Enumeration that identifies if this port is a Sink (inlet), a Source (outlet) or both a SinkAndSource."
        },
        "description": "The product IfcDistributionPort defines the occurrence of a specialized port for use within the context of distribution elements. Its type is defined by IfcDistributionPortType or its subtypes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcdistributionport.htm"
    },
    "IfcDocumentElectronicFormat": {
        "attributes": {
            "FileExtension": "File extension of electronic document used by computer operating system.",
            "MimeContentType": "Main Mime type (as published by W3C or as user defined application type)",
            "MimeSubtype": "Mime subtype information."
        },
        "description": "An IfcDocumentElectronicFormat captures the type of document being referenced as an external source,and for which metadata is specified by IfcDocumentInformation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcdocumentelectronicformat.htm"
    },
    "IfcDocumentInformation": {
        "attributes": {
            "Confidentiality": "The level of confidentiality of the document.",
            "CreationTime": "Date and time stamp when the document was originally created.",
            "Description": "Description of document and its content.",
            "DocumentId": "Identifier that uniquely identifies a document.",
            "DocumentOwner": "Information about the person and/or organization acknowledged as the 'owner' of this document. In some contexts, the document owner determines who has access to or editing right to the document.",
            "DocumentReferences": "Information on the referenced document.",
            "Editors": "The persons and/or organizations who have created this document or contributed to it.",
            "ElectronicFormat": "Describes the electronic format of the document being referenced, providing the file extension and the manner in which the content is provided.",
            "IntendedUse": "Intended use for this document.",
            "IsPointedTo": "An inverse relationship from the IfcDocumentInformationRelationship to the related documents.",
            "IsPointer": "An inverse relationship from the IfcDocumentInformationRelationship to the relating document.",
            "LastRevisionTime": "Date and time stamp when this document version was created.",
            "Name": "File name or document name assigned by owner.",
            "Purpose": "Purpose for this document.",
            "Revision": "Document revision designation",
            "Scope": "Scope for this document.",
            "Status": "The current status of the document. Examples of status values that might be used for a document information status include: - DRAFT - FINAL DRAFT - FINAL - REVISION",
            "ValidFrom": "Date, when the document becomes valid.",
            "ValidUntil": "Date until which the document remains valid."
        },
        "description": "An IfcDocumentInformation captures \"metadata\" of an external document. The actual content of the document is not defined in IFC ; instead, it can be found following the reference given to IfcDocumentReference.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcdocumentinformation.htm"
    },
    "IfcDocumentInformationRelationship": {
        "attributes": {
            "RelatedDocuments": "The document that acts as the child, referenced or replacing document in a relationship.",
            "RelatingDocument": "The document that acts as the parent, referencing or original document in a relationship.",
            "RelationshipType": "Describes the type of relationship between documents. This could be sub-document, replacement etc. The interpretation has to be established in an application context."
        },
        "description": "An IfcDocumentInformationRelationship is a relationship class that enables a document to have the ability to reference other documents.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcdocumentinformationrelationship.htm"
    },
    "IfcDocumentReference": {
        "attributes": {
            "ReferenceToDocument": "The document information that is being referenced."
        },
        "description": "An IfcDocumentReference is a reference to the location of a document. The reference is given by a system interpretable Location attribute (e.g., an URL string) or by a human readable location, where the document can be found, and an optional inherited internal reference ItemReference, which refers to a system interpretable position within the document. The optional inherited Name attribute is meant to have meaning for human readers. Optional document metadata can also be captured through reference to IfcDocumentInformation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcdocumentreference.htm"
    },
    "IfcDoor": {
        "attributes": {
            "OverallHeight": "Overall measure of the height, it reflects the Z Dimension of a bounding box, enclosing the ~~body of the~~ door opening. If omitted, the _OverallHeight_ should be taken from the geometric representation of the _IfcOpening_ in which the door is inserted.     >  NOTE  The body of the door might be taller then the door opening (e.g. in cases where the door lining includes a casing). In these cases the OverallHeight shall still be given as the door opening height, and not as the total height of the door lining.",
            "OverallWidth": "Overall measure of the width, it reflects the X Dimension of a bounding box, enclosing the ~~body of the~~ door opening. If omitted, the _OverallWidth_ should be taken from the geometric representation of the _IfcOpening_ in which the door is inserted.     >  NOTE  The body of the door might be wider then the door opening (e.g. in cases where the door lining includes a casing). In these cases the OverallWidth shall still be given as the door opening width, and not as the total width of the door lining."
        },
        "description": "Definition from ISO 6707-1:1989: Construction for closing an opening, intended primarily for access with hinged, pivoted or sliding operation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoor.htm"
    },
    "IfcDoorLiningProperties": {
        "attributes": {
            "CasingDepth": "Depth of the casing (dimension in plane perpendicular to door leaf). If given it is applied equally to all four sides of the adjacent wall.",
            "CasingThickness": "Thickness of the casing (dimension in plane of the door leaf). If given it is applied equally to all four sides of the adjacent wall.",
            "LiningDepth": "Depth of the door lining, measured perpendicular to the plane of the door lining. If omitted (and with a given value to lining thickness) it indicates an adjustable depth (i.e. a depth that adjusts to the thickness of the wall into which the occurrence of this door style is inserted).",
            "LiningOffset": "Offset (dimension in plane perpendicular to door leaf) of the door lining. The offset is given as distance to the x axis of the local placement.",
            "LiningThickness": "Thickness (width in plane parallel to door leaf) of the door lining.",
            "ShapeAspectStyle": "Pointer to the shape aspect, if given. The shape aspect reflects the part of the door shape, which represents the door lining.",
            "ThresholdDepth": "Depth (dimension in plane perpendicular to door leaf) of the door threshold. Only given if the door lining includes a threshold. If omitted (and with a given value to threshold thickness) it indicates an adjustable depth (i.e. a depth that adjusts to the thickness of the wall into which the occurrence of this door style is inserted).",
            "ThresholdOffset": "Offset (dimension in plane perpendicular to door leaf) of the door threshold. The offset is given as distance to the x axis of the local placement. Only given if the door lining includes a threshold and the parameter is known.",
            "ThresholdThickness": "Thickness (width in plane parallel to door leaf) of the door threshold. Only given if the door lining includes a threshold and the parameter is known.",
            "TransomOffset": "Offset of the transom (if given) which divides the door leaf from a glazing (or window) above. The offset is given from the bottom of the door opening.",
            "TransomThickness": "Thickness (width in plane parallel to door leaf) of the transom (if given) which divides the door leaf from a glazing (or window) above."
        },
        "description": "Definition of IAI: The door lining is the frame which enables the door leaf to be fixed in position. The door lining is used to hang the door leaf. The parameters of the door lining (IfcDoorLiningProperties) define the geometrically relevant parameter of the lining.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoorliningproperties.htm"
    },
    "IfcDoorPanelProperties": {
        "attributes": {
            "PanelDepth": "Depth of the door panel, measured perpendicular to the plane of the door leaf.",
            "PanelOperation": "The PanelOperation defines the way of operation of that panel. The PanelOperation of the door panel has to correspond with the OperationType of the IfcDoorStyle.",
            "PanelPosition": "Position of this panel within the door.",
            "PanelWidth": "Width of this panel, given as ratio relative to the total clear opening width of the door.",
            "ShapeAspectStyle": "Pointer to the shape aspect, if given. The shape aspect reflects the part of the door shape, which represents the door panel."
        },
        "description": "A description of the door panel. A door panel is normally a door leaf that opens to allow people or goods to pass. The parameters of the door panel define the geometrically relevant parameter of the panel,",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoorpanelproperties.htm"
    },
    "IfcDoorStyle": {
        "attributes": {
            "ConstructionType": "Type defining the basic construction and material type of the door.",
            "OperationType": "Type defining the general layout and operation of the door style.",
            "ParameterTakesPrecedence": "The Boolean value reflects, whether the parameter given in the attached lining and panel properties exactly define the geometry (TRUE), or whether the attached style shape take precedence (FALSE). In the last case the parameter have only informative value.",
            "Sizeable": "The Boolean indicates, whether the attached _IfcMappedRepresentation_ (if given) can be sized (using scale factor of transformation), or not (FALSE). If not, the _IfcMappedRepresentation_ should be _IfcShapeRepresentation_ of the _IfcDoor_ (using _IfcMappedItem_ as the _Item_) with the scale factor = 1."
        },
        "description": "Definition from IAI: The door style, IfcDoorStyle, defines a particular style of doors, which may be included into the spatial context of the building model through an (or multiple) instances of IfcDoor. A door style defines the overall parameter of the door style and refers to the particular parameter of the lining and one (or several) panels through the IfcDoorLiningProperties and the IfcDoorPanelProperties.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcdoorstyle.htm"
    },
    "IfcDraughtingCallout": {
        "attributes": {
            "Contents": "The annotation curves, symbols, or text comprising the presentation of information.",
            "IsRelatedFromCallout": "",
            "IsRelatedToCallout": ""
        },
        "description": "A draughting callout is a collection of annotated curves, symbols and text that presents some product shape or definition properties within a drawing.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdraughtingcallout.htm"
    },
    "IfcDraughtingCalloutRelationship": {
        "attributes": {
            "Description": "Additional informal description of the relationship.",
            "Name": "The word or group of words by which the relationship is referred to.",
            "RelatedDraughtingCallout": "The other of the draughting callouts which is a part of the relationship.",
            "RelatingDraughtingCallout": "One of the draughting callouts which is a part of the relationship."
        },
        "description": "The draughting callout relationship establishes a logical relationship between two draughting callouts. The meaning of this relationship is given at the subtypes of this entity.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcdraughtingcalloutrelationship.htm"
    },
    "IfcDraughtingPreDefinedColour": {
        "description": "The draughting pre defined colour is a pre defined colour for the purpose to identify a colour by name. Allowable names are:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcdraughtingpredefinedcolour.htm"
    },
    "IfcDraughtingPreDefinedCurveFont": {
        "description": "The draughting predefined curve font type defines a selection of widely used curve fonts for draughting purposes by name.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcdraughtingpredefinedcurvefont.htm"
    },
    "IfcDraughtingPreDefinedTextFont": {
        "description": "The draughting pre defined text font is a pre defined text font for the purpose to identify a font by name. Allowable names are:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcdraughtingpredefinedtextfont.htm"
    },
    "IfcDuctFittingType": {
        "description": "The element type IfcDuctFittingType defines a list of commonly shared property set definitions of a duct fitting and an optional set of product representations. It is used to define an duct fitting specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "BEND": "A fitting with typically two ports used to change the direction of flow between connected elements.",
            "CONNECTOR": "Connector fitting, typically used to join two ports together within a flow distribution system (e.g., a coupling used to join two duct segments).",
            "ENTRY": "Entry fitting, typically unconnected at one port and connected to a flow distribution system at the other (e.g., an outside air duct system intake opening).",
            "EXIT": "Exit fitting, typically unconnected at one port and connected to a flow distribution system at the other (e.g., an exhaust air discharge opening).",
            "JUNCTION": "A fitting with typically more than two ports used to redistribute flow among the ports and/or to change the direction of flow between connected elements (e.g, tee, cross, wye, etc.).",
            "NOTDEFINED": "Undefined fitting.",
            "OBSTRUCTION": "A fitting with typically two ports used to obstruct or restrict flow between the connected elements (e.g., screen, perforated plate, etc.).",
            "TRANSITION": "A fitting with typically two ports having different shapes or sizes. Can also be used to change the direction of flow between connected elements.",
            "USERDEFINED": "User-defined fitting."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcductfittingtype.htm"
    },
    "IfcDuctSegmentType": {
        "description": "The element type IfcDuctSegmentType defines a list of commonly shared property set definitions of a duct segment and an optional set of product representations. It is used to define a duct segment specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "FLEXIBLESEGMENT": "A flexible segment is a continuous non-linear segment of duct that can be deformed and change the direction of flow.",
            "NOTDEFINED": "Undefined segment.",
            "RIGIDSEGMENT": "A rigid segment is a continuous linear segment of duct that cannot be deformed.",
            "USERDEFINED": "User-defined segment."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcductsegmenttype.htm"
    },
    "IfcDuctSilencerType": {
        "description": "The element type IfcDuctSilencerType defines a list of commonly shared property set definitions of a duct silencer and an optional set of product representations. It is used to define a duct silencer specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "FLATOVAL": "Flat-oval shaped duct silencer type.",
            "NOTDEFINED": "Undefined duct silencer type.",
            "RECTANGULAR": "Rectangular shaped duct silencer type.",
            "ROUND": "Round duct silencer type.",
            "USERDEFINED": "User-defined duct silencer type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcductsilencertype.htm"
    },
    "IfcEdge": {
        "attributes": {
            "EdgeEnd": "End point (vertex) of the edge. The same vertex can be used for both EdgeStart and EdgeEnd.",
            "EdgeStart": "Start point (vertex) of the edge."
        },
        "description": "Definition from ISO/CD 10303-42:1992: An edge is the topological construct corresponding to the connection of two vertices. More abstractly, it may stand for a logical relationship between two vertices. The domain of an edge, if present, is a finite, non-self-intersecting open curve in R^M^, that is, a connected 1-dimensional manifold. The bounds of an edge are two vertices, which need not be distinct. The edge is oriented by choosing its traversal direction to run from the first to the second vertex. If the two vertices are the same, the edge is a self loop. The domain of the edge does not include its bounds, and 0 \u2264 \u039e \u2264 \u221e. Associated with an edge may be a geometric curve to locate the edge in a coordinate space; this is represented by the edge curve (IfcEdgeCurve) subtype. The curve shall be finite and non-self-intersecting within the domain of the edge. An edge is a graph, so its multiplicity M and graph genus G^e^ may be determined by the graph traversal algorithm. Since M = E = 1, the Euler equation (1) reduces in the case to",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcedge.htm"
    },
    "IfcEdgeCurve": {
        "attributes": {
            "EdgeGeometry": "The curve which defines the shape and spatial location of the edge. This curve may be unbounded and is implicitly trimmed by the vertices of the edge; this defines the edge domain. Multiple edges can reference the same curve.",
            "SameSense": "This logical flag indicates whether (TRUE), or not (FALSE) the senses of the edge and the curve defining the edge geometry are the same. The sense of an edge is from the edge start vertex to the edge end vertex; the sense of a curve is in the direction of increasing parameter."
        },
        "description": "Definition from ISO/CD 10303-42:1992: An edge curve is a special subtype of edge which has its geometry fully defined. The geometry is defined by associating the edge with a curve which may be unbounded. As the topological and geometric directions may be opposed, an indicator (same sense) is used to identify whether the edge and curve directions agree or are opposed. The Boolean value indicates whether the curve direction agrees with (TRUE) or is in the opposite direction (FALSE) to the edge direction. Any geometry associated with the vertices of the edge shall be consistent with the edge geometry.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcedgecurve.htm"
    },
    "IfcEdgeFeature": {
        "attributes": {
            "FeatureLength": "The length of the feature in orthogonal direction from the feature cross section."
        },
        "description": "A feature describing the edge shape of an building element.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcedgefeature.htm"
    },
    "IfcEdgeLoop": {
        "attributes": {
            "EdgeList": "A list of oriented edge entities which are concatenated together to form this path.",
            "Ne": "The number of elements in the edge list. SIZEOF(EdgeList)"
        },
        "description": "Definition from ISO/CD 10303-42:1992: An edge_loop is a loop with nonzero extent. It is a path in which the start and end vertices are the same. Its domain, if present, is a closed curve. An edge_loop may overlap itself.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcedgeloop.htm"
    },
    "IfcElectricApplianceType": {
        "description": "An IfcElectricApplianceType defines a particular type of common electrical appliance found in a typical AEC/FM facility. Electrical Appliances generally consist of electrical devices that are not a fixed part of the building but instead can be moved from one space to another and are powered with electricity.",
        "predefined_types": {
            "COMPUTER": "",
            "DIRECTWATERHEATER": "",
            "DISHWASHER": "An appliance that has the primary function of washing dishes.",
            "ELECTRICCOOKER": "An electrical appliance that has the primary function of cooking food (including oven, hob, grill).",
            "ELECTRICHEATER": "",
            "FACSIMILE": "",
            "FREESTANDINGFAN": "An electrical appliance that is used occasionally to provide ventilation. A freestanding fan is a 'plugged' appliance whose load may be removed from an electric circuit.",
            "FREEZER": "An electrical appliance that has the primary function of storing food at temperatures below the freezing point of water.",
            "FRIDGE_FREEZER": "An electrical appliance that combines the functions of a freezer and a refrigerator through the provision of separate compartments.",
            "HANDDRYER": "An electrical appliance that has the primary function of drying hands.",
            "INDIRECTWATERHEATER": "",
            "MICROWAVE": "An electrical appliance that has the primary function of cooking food using microwaves.",
            "NOTDEFINED": "Undefined type.",
            "PHOTOCOPIER": "A machine that has the primary function of reproduction of printed matter.",
            "PRINTER": "",
            "RADIANTHEATER": "",
            "REFRIGERATOR": "An electrical appliance that has the primary function of storing food at low temperature but above the freezing point of water.",
            "SCANNER": "",
            "TELEPHONE": "",
            "TUMBLEDRYER": "An electrical appliance that has the primary function of drying clothes.",
            "TV": "",
            "USERDEFINED": "User-defined type.",
            "VENDINGMACHINE": "An appliance that stores and vends goods including food, drink and goods of various types.",
            "WASHINGMACHINE": "An appliance that has the primary function of washing clothes.",
            "WATERCOOLER": "",
            "WATERHEATER": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricappliancetype.htm"
    },
    "IfcElectricDistributionPoint": {
        "attributes": {
            "DistributionPointFunction": "Identifies the functions or purposes that a distribution point may fulfill from which that required may be selected.",
            "UserDefinedFunction": ""
        },
        "description": "An IfcElectricDistributionPoint is a flow controller in which instances of electrical devices are brought together at a single place for a particular purpose",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricdistributionpoint.htm"
    },
    "IfcElectricFlowStorageDeviceType": {
        "description": "An IfcElectricFlowStorageDeviceType is a device in which electrical energy is stored and from which energy may be progressively released.",
        "predefined_types": {
            "BATTERY": "A device for storing energy in chemical form so that it can be released as electrical energy.",
            "CAPACITORBANK": "A device that stores electrical energy when an external power supply is present using the electrical property of capacitance.",
            "HARMONICFILTER": "A device that constantly injects currents that precisely correspond to the harmonic components drawn by the load.",
            "INDUCTORBANK": "",
            "NOTDEFINED": "Undefined type.",
            "UPS": "A device that provides a time limited alternative source of power supply in the event of failure of the main supply.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricflowstoragedevicetype.htm"
    },
    "IfcElectricGeneratorType": {
        "description": "An IfcElectricGeneratorType defines a particular type of engine that is a machine for converting mechanical energy into electrical energy.",
        "predefined_types": {
            "NOTDEFINED": "Undefined type.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricgeneratortype.htm"
    },
    "IfcElectricHeaterType": {
        "description": "An IfcElectricHeaterType is a device that emits electrical energy as heat.",
        "predefined_types": {
            "ELECTRICCABLEHEATER": "",
            "ELECTRICMATHEATER": "",
            "ELECTRICPOINTHEATER": "",
            "NOTDEFINED": "",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricheatertype.htm"
    },
    "IfcElectricMotorType": {
        "description": "Definition from BS6100 310 5201: An IfcElectricMotorType defines a particular type of engine that is a machine for converting electrical energy into mechanical energy.",
        "predefined_types": {
            "DC": "A motor using either generated or rectified Direct Current (DC) power.",
            "INDUCTION": "An alternating current motor in which the primary winding on one member (usually the stator) is connected to the power source and a secondary winding or a squirrel-cage secondary winding on the other member (usually the rotor) carries the induced current. There is no physical electrical connection to the secondary winding, its current is induced.",
            "NOTDEFINED": "Undefined type.",
            "POLYPHASE": "A two or three-phase induction motor in which the windings, one for each phase, are evenly divided by the same number of electrical degrees.",
            "RELUCTANCESYNCHRONOUS": "A synchronous motor with a special rotor design which directly lines the rotor up with the rotating magnetic field of the stator, allowing for no slip under load.",
            "SYNCHRONOUS": "A motor that operates at a constant speed up to full load. The rotor speed is equal to the speed of the rotating magnetic field of the stator; there is no slip.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricmotortype.htm"
    },
    "IfcElectricTimeControlType": {
        "description": "An IfcElectricTimeControlType is a device that applies control to the provision or flow of electrical energy over time.",
        "predefined_types": {
            "NOTDEFINED": "Undefined type.",
            "RELAY": "Electromagnetically operated contactor for making or breaking a control circuit.",
            "TIMECLOCK": "A control that causes action to occur at set times.",
            "TIMEDELAY": "A control that causes action to occur following a set duration.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectrictimecontroltype.htm"
    },
    "IfcElectricalBaseProperties": {
        "attributes": {
            "ElectricCurrentType": "Type of electrical current applied",
            "FullLoadCurrent": "Full load electrical current requirements.",
            "InputFrequency": "Nominal frequency of input voltage wave form.",
            "InputPhase": "Relative phase of input conductors",
            "InputVoltage": "Input electrical potential",
            "MaximumPowerInput": "Maximum power input of the electrical device",
            "MinimumCircuitCurrent": "Minimum current carrying capacity of the electrical circuit.",
            "RatedPowerInput": "Actual electrical input power of the electrical device at its rated capacity"
        },
        "description": "Common definition to capture basic electrical characteristics for use in building services and facilities management.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcelectricalbaseproperties.htm"
    },
    "IfcElectricalCircuit": {
        "description": "An IfcElectricalCircuit defines a particular type of system that is for the purpose of distributing electrical power.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcelectricalcircuit.htm"
    },
    "IfcElectricalElement": {
        "description": "Generalization of all electrical related objects.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelectricalelement.htm"
    },
    "IfcElement": {
        "attributes": {
            "ConnectedFrom": "Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element.",
            "ConnectedTo": "Reference to the element connection relationship. The relationship then refers to the other element to which this element is connected to.",
            "ContainedInStructure": "Containment relationship to the spatial structure element, to which the element is primarily associated.",
            "FillsVoids": "Reference to the Fills Relationship that puts the Element into the Opening within another Element.",
            "HasCoverings": "Reference to _IfcCovering_ by virtue of the objectified relationship _IfcRelCoversBldgElement_. It defines the concept of an element having coverings attached.",
            "HasOpenings": "Reference to the Voids Relationship that creates an opening in an element. An element can incorporate zero-to-many openings.",
            "HasPorts": "Reference to the element to port connection relationship. The relationship then refers to the port which is contained in this element.",
            "HasProjections": "Projection relationship that adds a feature (using a Boolean union) to the _IfcBuildingElement_.",
            "HasStructuralMember": "",
            "IsConnectionRealization": "Reference to the connection relationship with realizing element. The relationship then refers to the realizing element which provides the physical manifestation of the connection relationship.",
            "ProvidesBoundaries": "Reference to Space Boundaries by virtue of the objectified relationship IfcRelSeparatesSpaces. It defines the concept of an Building Element bounding Spaces.",
            "ReferencedInStructures": "Reference relationship to the spatial structure element, to which the element is additionally associated.",
            "Tag": "The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level."
        },
        "description": "Generalization of all components that make up an AEC product. Those elements can be logically contained by a spatial structure element that constitutes a certain level within a project structure hierarchy (e.g., site, building, storey or space). This is done by using the IfcRelContainedInSpatialStructure relationship.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelement.htm"
    },
    "IfcElementAssembly": {
        "attributes": {
            "AssemblyPlace": "A designation of where the assembly is intended to take place defined by an Enum."
        },
        "description": "A container class that represents complex element assemblies aggregated from several elements, such as discrete elements, building elements, or other elements.",
        "predefined_types": {
            "ACCESSORY_ASSEMBLY": "Assembled accessories or components.",
            "ARCH": "A curved structure.",
            "BEAM_GRID": "Interconnected beams, located in one (typically horizontal) plane.",
            "BRACED_FRAME": "A rigid frame with additional bracing members.",
            "GIRDER": "A beam-like superstructure.",
            "NOTDEFINED": "Undefined element assembly.",
            "REINFORCEMENT_UNIT": "Assembled reinforcement elements.",
            "RIGID_FRAME": "A structure built up of beams, columns, etc. with moment-resisting joints.",
            "SLAB_FIELD": "Slabs, laid out in one plane.",
            "TRUSS": "A structure built up of members with (quasi) pinned joint.",
            "USERDEFINED": "User-defined element assembly."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelementassembly.htm"
    },
    "IfcElementComponent": {
        "description": "An element component is a representation for minor items included in, added to or connecting to or between elements, which usually are not of interest from the overall building structure viewpoint. However, these small parts may have vital and load carrying functions within the construction. These items do not provide any actual space boundaries. Typical examples of _IfcElementComponent_s include different kinds of fasteners and various accessories.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcelementcomponent.htm"
    },
    "IfcElementComponentType": {
        "description": "The element type (IfcElementComponentType) represents the supertype for element types which define lists of commonly shared property set definitions of various small parts and accessories and an optional set of product representations. It is used to define a supporting element mainly within structural and building services domains (i.e. the specific type information common to all occurrences of that type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcelementcomponenttype.htm"
    },
    "IfcElementQuantity": {
        "attributes": {
            "MethodOfMeasurement": "Name of the method of measurement used to calculate the element quantity. The method of measurement attribute has to be made recognizable by further agreements.",
            "Quantities": "The individual quantities for the element, can be a set of length, area, volume, weight or count based quantities."
        },
        "description": "An IfcElementQuantity defines a set of derived measures of an element's physical property. Elements could be spatial structure elements (like buildings, storeys, or spaces) or building elements (like walls, slabs, finishes). The IfcElementQuantity gets assigned to the element by using the IfcRelDefinesByProperties relationship.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelementquantity.htm"
    },
    "IfcElementType": {
        "attributes": {
            "ElementType": "The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute 'PredefinedType' is set to USERDEFINED."
        },
        "description": "The IfcElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcelementtype.htm"
    },
    "IfcElementarySurface": {
        "attributes": {
            "Dim": "The space dimensionality of this class, derived from the dimensionality of the Position. Position.Dim",
            "Position": "The position and orientation of the surface. This attribute is used in the definition of the parameterization of the surface."
        },
        "description": "Definition from ISO/CD 10303-42:1992: An elementary surface (IfcElementarySurface) is a simple analytic surface with defined parametric representation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcelementarysurface.htm"
    },
    "IfcEllipse": {
        "attributes": {
            "SemiAxis1": "The first radius of the ellipse which shall be positive. Placement.Axes[1] gives the direction of the SemiAxis1.",
            "SemiAxis2": "The second radius of the ellipse which shall be positive."
        },
        "description": "Definition from ISO/CD 10303-42:1992: An ellipse (IfcEllipse) is a conic section defined by the lengths of the semi-major and semi-minor diameters and the position (center or mid point of the line joining the foci) and orientation of the curve. Interpretation of the data shall be as follows:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcellipse.htm"
    },
    "IfcEllipseProfileDef": {
        "attributes": {
            "SemiAxis1": "The first radius of the ellipse. It is measured along the direction of Position.P[1].",
            "SemiAxis2": "The second radius of the ellipse. It is measured along the direction of Position.P[2]."
        },
        "description": "Definition from IAI: The IfcEllipseProfileDef defines an ellipse as the profile definition used by the swept surface geometry or the swept area solid. It is given by its semi axis attributes and placed within the 2D position coordinate system, established by the Position attribute.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcellipseprofiledef.htm"
    },
    "IfcEnergyConversionDevice": {
        "description": "The distribution flow element IfcEnergyConversionDevice defines the occurrence of a device used to perform energy conversion or heat transfer and typically participates in a flow distribution system. Its type is defined by IfcEnergyConversionDeviceType or its subtypes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcenergyconversiondevice.htm"
    },
    "IfcEnergyConversionDeviceType": {
        "description": "The element type IfcEnergyConversionType defines a list of commonly shared property set definitions of an energy conversion device and an optional set of product representations. It is used to define an energy conversion device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcenergyconversiondevicetype.htm"
    },
    "IfcEnergyProperties": {
        "attributes": {
            "EnergySequence": "",
            "UserDefinedEnergySequence": "This attribute must be defined if the EnergySequence is USERDEFINED."
        },
        "description": "Common definition to capture the properties of an energy source typically used within the context of building services.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcenergyproperties.htm"
    },
    "IfcEnvironmentalImpactValue": {
        "attributes": {
            "Category": "The category into which the environmental impact value falls.",
            "ImpactType": "Specification of the environmental impact type to be referenced.",
            "UserDefinedCategory": "A user defined value category into which the environmental impact value falls."
        },
        "description": "An IfcEnvironmentalImpactValue is an amount or measure of an environmental impact or a value that affects an amount or measure of an environmental impact.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcenvironmentalimpactvalue.htm"
    },
    "IfcEquipmentElement": {
        "description": "Generalization of all equipment related objects, those objects are characterized as being pre-manufactured and being movable, and which provide some building service related or other servicing function. The term fixture is often used as a synonym or similar concept. The IfcEquipmentElement covers the fixture aspect as well.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcequipmentelement.htm"
    },
    "IfcEquipmentStandard": {
        "description": "An IfcEquipmentStandard is a standard for equipment allocation that can be assigned to persons within an organization.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcequipmentstandard.htm"
    },
    "IfcEvaporativeCoolerType": {
        "description": "The element type IfcEvaporativeCoolerType defines a list of commonly shared property set definitions of an evaporative cooler and an optional set of product representations. It is used to define an evaporative cooler specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "DIRECTEVAPORATIVEAIRWASHER": "Direct evaporative air washer: Cools the air stream by evaporating water dircectly into the air stream using coolers with spray-type air washer consist of a chamber or casing containing spray nozzles, and tank for collecting spray water, and an eliminator section for removing entrained drops of water from the air.",
            "DIRECTEVAPORATIVEPACKAGEDROTARYAIRCOOLER": "Direct evaporative packaged rotary air cooler: Cools the air stream by evaporating water dircectly into the air stream using coolers that wet and wash the evaporative pad by rotating it through a water bath.",
            "DIRECTEVAPORATIVERANDOMMEDIAAIRCOOLER": "Direct evaporative random media air cooler: Cools the air stream by evaporating water dircectly into the air stream using coolers with evaporative pads, usually of aspen wood or plastic fiber/foam.",
            "DIRECTEVAPORATIVERIGIDMEDIAAIRCOOLER": "Direct evaporative rigid media air cooler: Cools the air stream by evaporating water dircectly into the air stream using coolers with sheets of rigid, corrugated material as the wetted surface.",
            "DIRECTEVAPORATIVESLINGERSPACKAGEDAIRCOOLER": "Direct evaporative slingers packaged air cooler: Cools the air stream by evaporating water dircectly into the air stream using coolers with a water slinger in an evaporative cooling section and a fan section.",
            "INDIRECTDIRECTCOMBINATION": "Indirect/Direct combination: Cools the air stream by evaporating water indirectly and without adding moisture into the air stream using a two-stage cooler with a first-stage indirect evaporative cooler and second-stage direct evaporative cooler.",
            "INDIRECTEVAPORATIVECOOLINGTOWERORCOILCOOLER": "Indirect evaporative cooling tower or coil cooler: Cools the air stream by evaporating water indirectly and without adding moisture into the air stream using a combination of a cooling tower or other evaporative water cooler with a water-to-air heat exchanger coil and water circulating pump.",
            "INDIRECTEVAPORATIVEPACKAGEAIRCOOLER": "Indirect evaporative package air cooler: Cools the air stream by evaporating water indirectly and without adding moisture into the air stream. On one side of the heat exchanger, the secondary air stream is cooled by evaporation, while on the other side of heat exchanger, the primary air stream (conditioned air to be supplied to the room) is sensibly cooled by the heat exchanger surfaces.",
            "INDIRECTEVAPORATIVEWETCOIL": "Indirect evaporative wet coil: Cools the air stream by evaporating water indirectly and without adding moisture into the air stream. Water is sprayed directly on the tubes of the heat exchanger where latent cooling takes place and the vaporization of the water on the outside of the heat exchanger tubes allows the simultaneous heat and mass transfer which removes heat from the supply air on the tube side.",
            "NOTDEFINED": "Undefined evaporative cooler type.",
            "USERDEFINED": "User-defined evaporative cooler type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcevaporativecoolertype.htm"
    },
    "IfcEvaporatorType": {
        "description": "The element type IfcEvaporatorType defines a list of commonly shared property set definitions of an evaporator and an optional set of product representations. It is used to define an evaporator specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "DIRECTEXPANSIONBRAZEDPLATE": "Direct-expansion evaporator where a refrigerant evaporates inside plates brazed or welded together to make up an assembly of separate channels.",
            "DIRECTEXPANSIONSHELLANDTUBE": "Direct-expansion evaporator where a refrigerant evaporates inside a series of baffles that channel the fluid throughout the shell side.",
            "DIRECTEXPANSIONTUBEINTUBE": "Direct-expansion evaporator where a refrigerant evaporates inside one or more pairs of coaxial tubes.",
            "FLOODEDSHELLANDTUBE": "Evaporator in which refrigerant evaporates outside tubes.",
            "NOTDEFINED": "Undefined evaporator type.",
            "SHELLANDCOIL": "Evaporator in which refrigerant evaporates inside a simple coiled tube immersed in the fluid to be cooled.",
            "USERDEFINED": "User-defined evaporator type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcevaporatortype.htm"
    },
    "IfcExtendedMaterialProperties": {
        "attributes": {
            "Description": "Description for the set of extended properties.",
            "ExtendedProperties": "The set of material properties defined by user for this material.",
            "Name": "The name given to the set of extended properties."
        },
        "description": "A container class for user defined properties of associated material. This provides a mechanism to assign properties that have not been defined in IFC specification.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcextendedmaterialproperties.htm"
    },
    "IfcExternalReference": {
        "attributes": {
            "ItemReference": "Identifier for the referenced item in the external source (classification, document or library). The internal reference can provide a computer interpretable pointer into electronic source.",
            "Location": "Location, where the external source (classification, document or library). This can be either human readable or computer interpretable. For electronic location normally given as an URL location string, however other ways of accessing external references may be established in an application scenario.",
            "Name": "Optional name to further specify the reference. It can provide a human readable identifier (which does not necessarily need to have a counterpart in the internal structure of the document)."
        },
        "description": "An IfcExternalReference is the identification of information that is not explicitly represented in the current model or in the project database (as an implementation of the current model). Such information may be contained in classifications, documents or libraries.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifcexternalreference.htm"
    },
    "IfcExternallyDefinedHatchStyle": {
        "description": "Definition from ISO/CD 10303-46:1992: The externally defined hatch style is an entity which makes an external reference to a hatching style.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcexternallydefinedhatchstyle.htm"
    },
    "IfcExternallyDefinedSurfaceStyle": {
        "description": "Definition from IAI: Definition of a surface style through referencing an external source (e.g. a material library for rendering information).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcexternallydefinedsurfacestyle.htm"
    },
    "IfcExternallyDefinedSymbol": {
        "description": "An externally defined symbol is a symbol that gets its shape information by an agreed reference to an external source.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcexternallydefinedsymbol.htm"
    },
    "IfcExternallyDefinedTextFont": {
        "description": "Definition from ISO/CD 10303-46:1992: The externally defined text font is an external reference to a text font",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcexternallydefinedtextfont.htm"
    },
    "IfcExtrudedAreaSolid": {
        "attributes": {
            "Depth": "The distance the surface is to be swept.",
            "ExtrudedDirection": "The direction in which the surface is to be swept."
        },
        "description": "The extruded area solid (IfcExtrudedAreaSolid) is defined by sweeping a bounded planar surface. The direction of the extrusion is given by the ExtrudedDirection attribute and the length of the extrusion is given by the Depth attribute. If the planar area has inner boundaries, i.e. holes defined, then those holes shall be swept into holes of the solid.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcextrudedareasolid.htm"
    },
    "IfcFace": {
        "attributes": {
            "Bounds": "Boundaries of the face."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A face is a topological entity of dimensionality 2 corresponding to the intuitive notion of a piece of surface bounded by loops. Its domain, if present, is an oriented, connected, finite 2-manifold in R^m^. A face domain shall not have handles but it may have holes, each hole bounded by a loop. The domain of the underlying geometry of the face, if present, does not contain its bounds, and 0 < \u039e < \u221e.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcface.htm"
    },
    "IfcFaceBasedSurfaceModel": {
        "attributes": {
            "Dim": "The space dimensionality of this class, it is always 3. 3",
            "FbsmFaces": "The set of connected face sets comprising the face based surface model."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A face based surface model is described by a set of connected face sets of dimensionality 2. The connected face sets shall not intersect except at edges and vertices, except that a face in one connected face set may overlap a face in another connected face set, provided the face boundaries are identical. There shall be at least one connected face set.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcfacebasedsurfacemodel.htm"
    },
    "IfcFaceBound": {
        "attributes": {
            "Bound": "The loop which will be used as a face boundary.",
            "Orientation": "This indicated whether (TRUE) or not (FALSE) the loop has the same sense when used to bound the face as when first defined. If sense is FALSE the senses of all its component oriented edges are implicitly reversed when used in the face."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A face bound is a loop which is intended to be used for bounding a face.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcfacebound.htm"
    },
    "IfcFaceOuterBound": {
        "description": "Definition from ISO/CD 10303-42:1992: A face outer bound is a special subtype of face bound which carries the additional semantics of defining an outer boundary on the face. No more than one boundary of a face shall be of this type.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcfaceouterbound.htm"
    },
    "IfcFaceSurface": {
        "attributes": {
            "FaceSurface": "The surface which defines the internal shape of the face. This surface may be unbounded. The domain of the face is defined by this surface and the bounding loops in the inherited attribute SELF\\FaceBounds.",
            "SameSense": "This flag indicates whether the sense of the surface normal agrees with (TRUE), or opposes (FALSE), the sense of the topological normal to the face."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A face surface (IfcFaceSurface) is a subtype of face in which the geometry is defined by an associated surface. The portion of the surface used by the face shall be embeddable in the plane as an open disk, possibly with holes. However, the union of the face with the edges and vertices of its bounding loops need not be embeddable in the plane. It may, for example, cover an entire sphere or torus. As both a face and a geometric surface have defined normal directions, a BOOLEAN flag (the orientation attribute) is used to indicate whether the surface normal agrees with (TRUE) or is opposed to (FALSE) the face normal direction. The geometry associated with any component of the loops of the face shall be consistent with the surface geometry, in the sense that the domains of all the vertex points and edge curves are contained in the face geometry surface. A surface may be referenced by more than one face surface.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcfacesurface.htm"
    },
    "IfcFacetedBrep": {
        "description": "Definition from ISO/CD 10303-42:1992: A faceted brep is a simple form of boundary representation model in which all faces are planar and all edges are straight lines. Unlike the B-rep model, edges and vertices are not represented explicitly in the model but are implicitly available through the poly loop entity. A faceted B-rep has to meet the same topological constraints as the manifold solid Brep.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcfacetedbrep.htm"
    },
    "IfcFacetedBrepWithVoids": {
        "attributes": {
            "Voids": "Set of closed shells defining voids within the solid."
        },
        "description": "The IfcFacetedBrepWithVoids is a specialization of a faceted B-rep which contains one or more voids in its interior. The voids are represented as closed shells which are defined so that the shell normal point into the void.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcfacetedbrepwithvoids.htm"
    },
    "IfcFailureConnectionCondition": {
        "attributes": {
            "CompressionFailureX": "Compression force in x-direction leading to failure of the connection.",
            "CompressionFailureY": "Compression force in y-direction leading to failure of the connection.",
            "CompressionFailureZ": "Compression force in z-direction leading to failure of the connection.",
            "TensionFailureX": "Tension force in x-direction leading to failure of the connection.",
            "TensionFailureY": "Tension force in y-direction leading to failure of the connection.",
            "TensionFailureZ": "Tension force in z-direction leading to failure of the connection."
        },
        "description": "Instances of the entity IfcFailureConnectionCondition shall be used to describe connection properties needed to specify the failure of a connection.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcfailureconnectioncondition.htm"
    },
    "IfcFanType": {
        "description": "The element type IfcFanType defines a list of commonly shared property set definitions of a fan and an optional set of product representations. It is used to define a fan specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "CENTRIFUGALAIRFOIL": "Air flows through the impeller radially using blades that are airfoil shaped.",
            "CENTRIFUGALBACKWARDINCLINEDCURVED": "Air flows through the impeller radially using blades that are backward curved.",
            "CENTRIFUGALFORWARDCURVED": "Air flows through the impeller radially using blades that are forward curved.",
            "CENTRIFUGALRADIAL": "Air flows through the impeller radially using blades that are uncurved or slightly forward curved.",
            "NOTDEFINED": "Undefined fan type.",
            "PROPELLORAXIAL": "Air flows through the impeller axially and small hub-to-tip ratio impeller mounted in an orifice plate or inlet ring.",
            "TUBEAXIAL": "Air flows through the impeller axially with guide vanes and reduced running blade tip clearance.",
            "USERDEFINED": "User-defined fan type.",
            "VANEAXIAL": "Air flows through the impeller axially with guide vanes and reduced running blade tip clearance."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcfantype.htm"
    },
    "IfcFastener": {
        "description": "Representations of fixing parts which are used as fasteners to connect or join elements with other elements.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcfastener.htm"
    },
    "IfcFastenerType": {
        "description": "The element type (IfcFastenerType) defines a list of commonly shared property set definitions of a fastener and an optional set of product representations. It is used to define fasteners mainly within structural and building services domains (i.e. the specific type information common to all occurrences of that type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcfastenertype.htm"
    },
    "IfcFeatureElement": {
        "description": "Generalization of all existence dependent elements which modify the shape and appearance of the associated master element. The IfcFeatureElement offers the ability to handle shape modifiers as semantic objects within the IFC object model.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcfeatureelement.htm"
    },
    "IfcFeatureElementAddition": {
        "attributes": {
            "ProjectsElements": "Reference to the _IfcRelProjectsElement_ relationship that uses this _IfcFeatureElementAddition_ to create a volume addition at an element. The _IfcFeatureElementAddition_ can only be used to create a single addition at a single element using Boolean addition operation."
        },
        "description": "A specialization of the general feature element, that represents an existence dependent element which modifies the shape and appearance of the associated master element. The IfcFeatureElementAddition offers the ability to handle shape modifiers as semantic objects within the IFC object model that add to the shape of the master element.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcfeatureelementaddition.htm"
    },
    "IfcFeatureElementSubtraction": {
        "attributes": {
            "VoidsElements": "Reference to the Voids Relationship that uses this Opening Element to create a void within an Element. The Opening Element can only be used to create a single void within a single Element."
        },
        "description": "A specialization of the general feature element, that represents an existence dependent elements which modifies the shape and appearance of the associated master element. The IfcFeatureElementSubtraction offers the ability to handle shape modifiers as semantic objects within the IFC object model that subtract from the shape of the master element.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcfeatureelementsubtraction.htm"
    },
    "IfcFillAreaStyle": {
        "attributes": {
            "FillStyles": "The set of fill area styles to use in presenting visible curve segments, annotation fill areas or surfaces."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The style for filling visible curve segments, annotation fill areas or surfaces with tiles or hatches.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcfillareastyle.htm"
    },
    "IfcFillAreaStyleHatching": {
        "attributes": {
            "HatchLineAngle": "A plane angle measure determining the direction of the parallel hatching lines.",
            "HatchLineAppearance": "The curve style of the hatching lines. Any curve style pattern shall start at the origin of each hatch line.",
            "PatternStart": "A distance along the reference hatch line which is the start point for the curve style font pattern of the reference hatch line.   If not given, the start point of the curve style font pattern is at the (virtual) hatching coordinate system.",
            "PointOfReferenceHatchLine": "A Cartesian point which defines the offset of the reference hatch line from the origin of the (virtual) hatching coordinate system. The origin is used for mapping the fill area style hatching onto an annotation fill area or surface. The reference hatch line would then appear with this offset from the fill style target point.   If not given the reference hatch lines goes through the origin of the (virtual) hatching coordinate system.",
            "StartOfNextHatchLine": "A repetition factor that determines the distance between adjacent hatch lines."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The fill area style hatching defines a styled pattern of curves for hatching an annotation fill area or a surface.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcfillareastylehatching.htm"
    },
    "IfcFillAreaStyleTileSymbolWithStyle": {
        "attributes": {
            "Symbol": "A styled annotation symbol."
        },
        "description": "The fill area style tile symbol with style is a symbol that is used as a tile within an annotated tiling.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcfillareastyletilesymbolwithstyle.htm"
    },
    "IfcFillAreaStyleTiles": {
        "attributes": {
            "Tiles": "A set of constituents of the tile.",
            "TilingPattern": "A two direction repeat factor defining the shape and relative positioning of the tiles.",
            "TilingScale": "The scale factor applied to each tile as it is placed in the annotation fill area."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The fill area style tiles defines a two dimensional tile to be used for the filling of annotation fill areas or other closed regions. The content of a tile is defined by the tile set, and the placement of each tile determined by the filling pattern which indicates how to place tiles next to each other. Tiles or parts of tiles outside of the annotation fill area or closed region shall be clipped at the boundaries of the area or region.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcfillareastyletiles.htm"
    },
    "IfcFilterType": {
        "description": "The element type IfcFilterType defines a list of commonly shared property set definitions of a filter and an optional set of product representations. It is used to define a filter specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "AIRPARTICLEFILTER": "A filter used to remove particulates from air.",
            "NOTDEFINED": "Undefined filter type.",
            "ODORFILTER": "A filter used to remove odors from air.",
            "OILFILTER": "A filter used to remove particulates from oil.",
            "STRAINER": "A filter used to remove particulates from a fluid.",
            "USERDEFINED": "User-defined filter type.",
            "WATERFILTER": "A filter used to remove particulates from water."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcfiltertype.htm"
    },
    "IfcFireSuppressionTerminalType": {
        "description": "The IfcFireSuppressionTerminalType defines a particular type of IfcFlowTerminal that has the purpose of delivering a fluid (gas or liquid) that will suppress a fire.",
        "predefined_types": {
            "BREECHINGINLET": "Symmetrical pipe fitting that unites two or more inlets into a single pipe. A breeching inlet may be used on either a wet or dry riser. Used by fire services personnel for fast connection of fire appliance hose reels. May also be used for foam.",
            "FIREHYDRANT": "Device, fitted to a pipe, through which a temporary supply of water may be provided.  May also be termed a stand pipe.",
            "HOSEREEL": "A supporting framework on which a hose may be wound.",
            "NOTDEFINED": "Underined type.",
            "SPRINKLER": "Device for sprinkling water from a pipe under pressure over an area.",
            "SPRINKLERDEFLECTOR": "Device attached to a sprinkler to deflect the water flow into a spread pattern to cover the required area.",
            "USERDEFINED": "User-defined type"
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcplumbingfireprotectiondomain/lexical/ifcfiresuppressionterminaltype.htm"
    },
    "IfcFlowController": {
        "description": "The distribution flow element IfcFlowController defines the occurrence of elements of a distribution system that are used to regulate flow through a distribution system (e.g., damper, valve, switch, relay, etc.). Its type is defined by IfcFlowControllerType or its subtypes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowcontroller.htm"
    },
    "IfcFlowControllerType": {
        "description": "The element type IfcFlowControllerType defines a list of commonly shared property set definitions of a flow controller and an optional set of product representations. It is used to define a flow controller specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowcontrollertype.htm"
    },
    "IfcFlowFitting": {
        "description": "The distribution flow element IfcFlowFitting defines the occurrence of a junction or transition in a flow distribution system (e.g., elbow, tee, etc.). Its type is defined by IfcFlowFittingType or its subtypes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowfitting.htm"
    },
    "IfcFlowFittingType": {
        "description": "The element type IfcFlowFittingType defines a list of commonly shared property set definitions of a flow fitting and an optional set of product representations. It is used to define a flow fitting specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowfittingtype.htm"
    },
    "IfcFlowInstrumentType": {
        "description": "An IfcFlowInstrumentType defines a particular type of flow instrument that reads and displays the value of a particular property of a system at a point, or that displays the difference in the value of a property between two points.",
        "predefined_types": {
            "AMMETER": "A device that reads and displays the current flow in a circuit.",
            "FREQUENCYMETER": "A device that reads and displays the electrical frequency of an alternating current circuit.",
            "NOTDEFINED": "Undefined type.",
            "PHASEANGLEMETER": "A device that reads and displays the phase angle of a phase in a polyphase electrical circuit.",
            "POWERFACTORMETER": "A device that reads and displays the power factor of an electrical circuit.",
            "PRESSUREGAUGE": "A device that reads and displays a pressure value at a point or the pressure difference between two points.",
            "THERMOMETER": "A device that reads and displays a temperature value at a point.",
            "USERDEFINED": "User-defined type.",
            "VOLTMETER_PEAK": "A device that reads and displays the peak voltage in an electrical circuit.",
            "VOLTMETER_RMS": "A device that reads and displays the RMS (mean) voltage in an electrical circuit."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifcflowinstrumenttype.htm"
    },
    "IfcFlowMeterType": {
        "description": "The element type IfcFlowMeterType defines a list of commonly shared property set definitions of a flow meter and an optional set of product representations. It is used to define a flow meter specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "ELECTRICMETER": "",
            "ENERGYMETER": "An electric meter or energy meter is a device that measures the amount of electrical energy supplied to or produced by a residence, business or machine.",
            "FLOWMETER": "",
            "GASMETER": "A device that measures the quantity of a gas or fuel.",
            "NOTDEFINED": "Undefined meter type",
            "OILMETER": "A device that measures the quantity of oil.",
            "USERDEFINED": "User-defined meter type",
            "WATERMETER": "A device that measures the quantity of water."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcflowmetertype.htm"
    },
    "IfcFlowMovingDevice": {
        "description": "The distribution flow element IfcFlowMovingDevice defines the occurrence of an apparatus used to distribute, circulate or perform conveyance of fluids, including liquids and gases, and typically participates in a flow distribution system (e.g., pump, fan). Its type is defined by IfcFlowMovingDeviceType or its subtypes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowmovingdevice.htm"
    },
    "IfcFlowMovingDeviceType": {
        "description": "The element type IfcFlowMovingDeviceType defines a list of commonly shared property set definitions of a flow moving device and an optional set of product representations. It is used to define a flow moving device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowmovingdevicetype.htm"
    },
    "IfcFlowSegment": {
        "description": "The distribution flow element IfcFlowSegment defines the occurrence of a segment of a flow distribution system that is typically straight, contiguous and has two ports (e.g., a section of pipe or duct).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowsegment.htm"
    },
    "IfcFlowSegmentType": {
        "description": "The element type IfcFlowSegmentType defines a list of commonly shared property set definitions of a flow segment and an optional set of product representations. It is used to define a flow segment specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowsegmenttype.htm"
    },
    "IfcFlowStorageDevice": {
        "description": "The distribution flow element IfcFlowStorageDevice defines the occurrence of a device that participates in a distribution system and is used for temporary storage of a fluid such as a liquid or a gas (e.g., tank). Its type is defined by IfcFlowStorageDeviceType or its subtypes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowstoragedevice.htm"
    },
    "IfcFlowStorageDeviceType": {
        "description": "The element type IfcFlowStorageDeviceType defines a list of commonly shared property set definitions of a flow storage device and an optional set of product representations. It is used to define a flow storage device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowstoragedevicetype.htm"
    },
    "IfcFlowTerminal": {
        "description": "The distribution flow element IfcFlowTerminal defines the occurrence of a permanently attached element that acts as a terminus or beginning of a distribution system (e.g., air outlet, drain, water closet, sink, etc.). A terminal is typically a point at which a system interfaces with an external environment. Its type is defined by IfcFlowTerminalType or its subtypes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowterminal.htm"
    },
    "IfcFlowTerminalType": {
        "description": "The element type IfcFlowTerminalType defines a list of commonly shared property set definitions of a flow terminal and an optional set of product representations. It is used to define a flow terminal specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowterminaltype.htm"
    },
    "IfcFlowTreatmentDevice": {
        "description": "The distribution flow element IfcFlowTreatmentDevice defines the occurrence of a device typically used to remove unwanted matter from a fluid, either liquid or gas, and typically participates in a flow distribution system (e.g., air filter). Its type is defined by IfcFlowTreatmentDeviceType or its subtypes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowtreatmentdevice.htm"
    },
    "IfcFlowTreatmentDeviceType": {
        "description": "The element type IfcFlowTreatmentDeviceType defines a list of commonly shared property set definitions of a flow treatment device and an optional set of product representations. It is used to define a flow treatment device specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcflowtreatmentdevicetype.htm"
    },
    "IfcFluidFlowProperties": {
        "attributes": {
            "FlowConditionSingleValue": "Defines the flow condition as a percentage of the cross-sectional area.",
            "FlowConditionTimeSeries": "A times series defining the flow condition as a percentage of the cross-sectional area.",
            "FlowrateSingleValue": "The flow rate of the fluid. Either a mass or volumetric flow rate shall be defined.",
            "FlowrateTimeSeries": "A time series of flow rate values. Note that either volumetric or mass flow rate values should be specified.",
            "Fluid": "The properties of the fluid.",
            "PressureSingleValue": "The pressure of the fluid.",
            "PressureTimeSeries": "A time series of pressure values of the fluid.",
            "PropertySource": "The source of the fluid flow properties (e.g., are these design values, measured values, etc.).",
            "TemperatureSingleValue": "Temperature of the fluid. For air this value represents the dry bulb temperature.",
            "TemperatureTimeSeries": "Time series of fluid temperature values. For air, these values represent the dry bulb temperature.",
            "UserDefinedPropertySource": "This attribute must be defined if the PropertySource is USERDEFINED.",
            "VelocitySingleValue": "The velocity of the fluid.",
            "VelocityTimeSeries": "A time series of velocity values of the fluid.",
            "WetBulbTemperatureSingleValue": "Wet bulb temperature of the fluid; only applicable if the fluid is air.",
            "WetBulbTemperatureTimeSeries": "Time series of fluid wet bulb temperature values. These values are only applicable if the fluid is air."
        },
        "description": "Common definition to capture the basic flow properties of a fluid typically used within a flow distribution system.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcfluidflowproperties.htm"
    },
    "IfcFooting": {
        "description": "A part of the foundation of a structure that spreads and transmits the load directly to the soil.",
        "predefined_types": {
            "FOOTING_BEAM": "Footing elements that are in bending and are supported clear of the ground. They will normally span between piers, piles or pile caps. They are distinguished from beams in the building superstructure since they will normally require a lower grade of finish. They are distinguished from _STRIP_FOOTING_ since they are clear of the ground surface and hence require support to the lower face while the concrete is curing.",
            "NOTDEFINED": "The type of footing is not defined.",
            "PAD_FOOTING": "An element that transfers the load of a single column (possibly two) to the ground.",
            "PILE_CAP": "An element that transfers the load from a column or group of columns to a pier or pile or group of piers or piles.",
            "STRIP_FOOTING": "A linear element that transfers loads into the ground from either a continuous element, such as a wall, or from a series of elements, such as columns.",
            "USERDEFINED": "Special types of footings which meet specific local requirements."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcfooting.htm"
    },
    "IfcFuelProperties": {
        "attributes": {
            "CarbonContent": "The carbon content in the fuel. This is measured in weight of carbon per unit weight of fuel and is therefore unitless.",
            "CombustionTemperature": "Combustion temperature of the material when air is at 298 K and 100 kPa.",
            "HigherHeatingValue": "Higher Heating Value is defined as the amount of energy released (MJ/kg) when a fuel is burned completely, and H2O is in liquid form  in the combustion products.",
            "LowerHeatingValue": "Lower Heating Value is defined as the amount of energy released (MJ/kg) when a fuel is burned completely, and H2O is in vapor form  in the combustion products."
        },
        "description": "Common definition to capture the properties of fuel energy typically used within the context of building services and flow distribution systems.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcfuelproperties.htm"
    },
    "IfcFurnishingElement": {
        "description": "Generalization of all furniture related objects. Furnishing objects are characterized as being",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcfurnishingelement.htm"
    },
    "IfcFurnishingElementType": {
        "description": "The IfcFurnishingElementType defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcfurnishingelementtype.htm"
    },
    "IfcFurnitureStandard": {
        "description": "An IfcFurnitureStandard is a standard for furniture allocation that can be assigned to persons within an organization.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcfurniturestandard.htm"
    },
    "IfcFurnitureType": {
        "attributes": {
            "AssemblyPlace": "A designation of where the assembly is intended to take place defined by an Enum."
        },
        "description": "An IfcFurnitureType defines a particular type of item of furniture such as a table, desk, chair, filing cabinet etc.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcfurnituretype.htm"
    },
    "IfcGasTerminalType": {
        "description": "The element type IfcGasTerminalType defines a list of commonly shared property set definitions of a gas terminal and an optional set of product representations. It is used to define a gas terminal specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "GASAPPLIANCE": "",
            "GASBOOSTER": "",
            "GASBURNER": "",
            "NOTDEFINED": "",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcgasterminaltype.htm"
    },
    "IfcGeneralMaterialProperties": {
        "attributes": {
            "MassDensity": "Material mass density, usually measured in [kg/m3].",
            "MolecularWeight": "Molecular weight of material (typically gas), measured in g/mole.",
            "Porosity": "The void fraction of the total volume occupied by material (Vbr - Vnet)/Vbr [m3/m3]."
        },
        "description": "A container class with general material properties defined in IFC specification.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcgeneralmaterialproperties.htm"
    },
    "IfcGeneralProfileProperties": {
        "attributes": {
            "CrossSectionArea": "Cross sectional area of profile. Usually measured in [mm2].",
            "MaximumPlateThickness": "This value is needed for stress analysis and to handle buckling problems. It can also be derived from the given profile geometry and therefore it is only an optional feature allowing for an explicit description. Usually measured in [mm].",
            "MinimumPlateThickness": "This value is needed for stress analysis and to handle buckling problems. It can also be derived from the given profile geometry and therefore it is only an optional feature allowing for an explicit description. Usually measured in [mm].",
            "Perimeter": "Perimeter of the profile for calculating the surface area. Usually measured in [mm].",
            "PhysicalWeight": "Weight of an imaginary steel beam per length, as for example given by the national standards\t for this profile. Usually measured in [kg/m]."
        },
        "description": "This is a collection of properties applicable to all linear structural members having a profile definition.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcgeneralprofileproperties.htm"
    },
    "IfcGeometricCurveSet": {
        "description": "Definition from ISO/CD 10303-42:1992: A geometric curve set is a collection of two or three dimensional points and curves.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcgeometriccurveset.htm"
    },
    "IfcGeometricRepresentationContext": {
        "attributes": {
            "CoordinateSpaceDimension": "The integer dimension count of the coordinate space modeled in a geometric representation context.",
            "HasSubContexts": "The set of _IfcGeometricRepresentationSubContexts_ that refer to this _IfcGeometricRepresentationContext_.",
            "Precision": "Value of the model precision for geometric models. It is a double value (REAL), typically in 1E-5 to 1E-8 range, that indicates the tolerance under which two given points are still assumed to be identical. The value can be used e.g. to sets the maximum distance from an edge curve to the underlying face surface in brep models.",
            "TrueNorth": "Direction of the true north relative to the underlying coordinate system as established by the attribute _WorldCoordinateSystem_. It is given by a direction within the xy-plane of the underlying coordinate system. If not given, it defaults to the positive direction of the y-axis of the _WorldCoordinateSystem_.",
            "WorldCoordinateSystem": "Establishment of the engineering coordinate system (often referred to as the world coordinate system in CAD) for all representation contexts used by the project.  >   Note  it can be used to provide better numeric stability if the placement of the building(s) is far away from the origin. In most cases however it would be set to origin: (0.,0.,0.) and directions x(1.,0.,0.), y(0.,1.,0.), z(0.,0.,1.)."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A geometric representation context is a representation context in which the geometric representation items are geometrically founded. A geometric representation context is a distinct coordinate space, spatially unrelated to other coordinate spaces.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcgeometricrepresentationcontext.htm"
    },
    "IfcGeometricRepresentationItem": {
        "description": "Definition from ISO/CD 10303-43:1992: An geometric representation item is a representation item that has the additional meaning of having geometric position or orientation or both. This meaning is present by virtue of:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcgeometricrepresentationitem.htm"
    },
    "IfcGeometricRepresentationSubContext": {
        "attributes": {
            "CoordinateSpaceDimension": "ParentContext.CoordinateSpaceDimension",
            "ParentContext": "Parent context from which the sub context derives its world coordinate system, precision, space coordinate dimension and true north.",
            "Precision": "NVL(ParentContext.Precision,1.E-5)",
            "TargetScale": "The target plot scale of the representation  to which this representation context applies. >  Scale indicates the target plot scale for the representation sub context, all annotation styles are given in plot dimensions according to this target plot scale. If multiple instances of IfcGeometricRepresentationSubContext are given having the same TargetView value, the target plot scale  applies up to the next smaller scale, or up to unlimited small scale.     Note: Scale 1:100 (given as 0.01 within TargetScale) is bigger then 1:200 (given as 0.005 within TargetScale).",
            "TargetView": "Target view of the representation to which this representation context applies.",
            "TrueNorth": "NVL(ParentContext.TrueNorth,SELF.WorldCoordinateSystem.P[2])",
            "UserDefinedTargetView": "User defined target view, this attribute value shall be given, if the TargetView attribute is set to USERDEFINED.",
            "WorldCoordinateSystem": "ParentContext.WorldCoordinateSystem"
        },
        "description": "Definition from IAI: The IfcGeometricRepresentationSubContext defines the context that applies to several shape representations of a product being a sub context, sharing the WorldCoordinateSystem, CoordinateSpaceDimension, Precision and TrueNorth attributes with the parent IfcGeometricRepresentationContext.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcgeometricrepresentationsubcontext.htm"
    },
    "IfcGeometricSet": {
        "attributes": {
            "Dim": "The space dimensionality of this class, it is identical to the first element in the set. A where rule ensures that all elements have the same dimensionality. Elements[1].Dim",
            "Elements": "The geometric elements which make up the geometric set, these may be points, curves or surfaces; but are required to be of the same coordinate space dimensionality."
        },
        "description": "Definition from ISO/CD 10303-42:1992: This entity is intended for the transfer of models when a topological structure is not available.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcgeometricset.htm"
    },
    "IfcGrid": {
        "attributes": {
            "ContainedInStructure": "Relationship to a spatial structure element, to which the grid is primarily associated.",
            "UAxes": "List of grid axes defining the first row of grid lines.",
            "VAxes": "List of grid axes defining the second row of grid lines.",
            "WAxes": "List of grid axes defining the third row of grid lines. It may be given in the case of a triangular grid."
        },
        "description": "IfcGrid ia a planar design grid defined in 3D space used as an aid in locating structural and design elements. The position of the grid (ObjectPlacement) is defined by a 3D coordinate system (and thereby the design grid can be used in plan, section or in any position relative to the world coordinate system). The position can be relative to the object placement of other products or grids. The XY plane of the 3D coordinate system is used to place the grid axes, which are 2D curves (e.g., line, circle, trimmed curve, polyline, or composite curve).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcgrid.htm"
    },
    "IfcGridAxis": {
        "attributes": {
            "AxisCurve": "Underlying curve which provides the geometry for this grid axis.",
            "AxisTag": "The tag or name for this grid axis.",
            "HasIntersections": "The reference to a set of",
            "PartOfU": "If provided, the _IfcGridAxis_ is part of the _UAxes_ of _IfcGrid_.",
            "PartOfV": "If provided, the _IfcGridAxis_ is part of the _VAxes_ of _IfcGrid_.",
            "PartOfW": "If provided, the _IfcGridAxis_ is part of the _WAxes_ of _IfcGrid_.",
            "SameSense": "Defines whether the original sense of curve is used or whether it is reversed in the context of the grid axis."
        },
        "description": "An individual axis, the IfcGridAxis, is defined in the context of a design grid. The axis definition is based on a curve of dimensionality 2. The grid axis is positioned within the XY plane of the position coordinate system defined by the IfcDesignGrid.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcgridaxis.htm"
    },
    "IfcGridPlacement": {
        "attributes": {
            "PlacementLocation": "A constraint on one or both ends of the path for an ExtrudedSolid.",
            "PlacementRefDirection": "Reference to a second grid axis intersection, which defines the orientation of the grid placement."
        },
        "description": "The IfcGridPlacement provides a specialization of IfcObjectPlacement in which the placement and axis direction of the object coordinate system is defined by a reference to the design grid as defined in IfcGrid.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcgridplacement.htm"
    },
    "IfcGroup": {
        "attributes": {
            "IsGroupedBy": "Contains the relationship that assigns the group members to the group object."
        },
        "description": "The IfcGroup is an generalization of any arbitrary group. A group is a logical collection of objects. It does not have its own position, nor can it hold its own shape representation. Therefore a group is an aggregation under some non-geometrical / topological grouping aspects.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcgroup.htm"
    },
    "IfcHalfSpaceSolid": {
        "attributes": {
            "AgreementFlag": "The agreement flag is TRUE if the normal to the BaseSurface points away from the material of the IfcHalfSpaceSolid. Otherwise it is FALSE.",
            "BaseSurface": "Surface defining side of half space.",
            "Dim": "The space dimensionality of this class, it is always 3 3"
        },
        "description": "Definition from ISO/CD 10303-42:1992: A half space solid is defined by the half space which is the regular subset of the domain which lies on one side of an unbounded surface. The side of the surface which is in the half space is determined by the surface normal and the agreement flag. If the agreement flag is TRUE, then the subset is the one the normal points away from. If the agreement flag is FALSE, then the subset is the one the normal points into. For a valid half space solid the surface shall divide the domain into exactly two subsets. Also, within the domain the surface shall be manifold and all surface normals shall point into the same subset.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifchalfspacesolid.htm"
    },
    "IfcHeatExchangerType": {
        "description": "The element type IfcHeatExchangerType defines a list of commonly shared property set definitions of a heat exchanger and an optional set of product representations. It is used to define a heat exchanger specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "NOTDEFINED": "Undefined heat exchanger type.",
            "PLATE": "Plate heat exchanger.",
            "SHELLANDTUBE": "Shell and Tube heat exchanger.",
            "USERDEFINED": "User-defined heat exchanger type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcheatexchangertype.htm"
    },
    "IfcHumidifierType": {
        "description": "The element type IfcHumidifierType defines a list of commonly shared property set definitions of a humidifier and an optional set of product representations. It is used to define a humidifier specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "ADIABATICAIRWASHER": "Water vapor is added into the airstream through adiabatic evaporation using an air washing element.",
            "ADIABATICATOMIZING": "Water vapor is added into the airstream through adiabatic evaporation using an atomizing element.",
            "ADIABATICCOMPRESSEDAIRNOZZLE": "Water vapor is added into the airstream through adiabatic evaporation using a compressed air nozzle.",
            "ADIABATICPAN": "Water vapor is added into the airstream through adiabatic evaporation using a pan.",
            "ADIABATICRIGIDMEDIA": "Water vapor is added into the airstream through adiabatic evaporation using a rigid media.",
            "ADIABATICULTRASONIC": "Water vapor is added into the airstream through adiabatic evaporation using an ultrasonic element.",
            "ADIABATICWETTEDELEMENT": "Water vapor is added into the airstream through adiabatic evaporation using a wetted element.",
            "ASSISTEDBUTANE": "Water vapor is added into the airstream through water heated evaporation using a butane heater.",
            "ASSISTEDELECTRIC": "Water vapor is added into the airstream through water heated evaporation using an electric heater.",
            "ASSISTEDNATURALGAS": "Water vapor is added into the airstream through water heated evaporation using a natural gas heater.",
            "ASSISTEDPROPANE": "Water vapor is added into the airstream through water heated evaporation using a propane heater.",
            "ASSISTEDSTEAM": "Water vapor is added into the airstream through water heated evaporation using a steam heater.",
            "NOTDEFINED": "Undefined humidifier type.",
            "STEAMINJECTION": "Water vapor is added into the airstream through direct steam injection.",
            "USERDEFINED": "User-defined humidifier type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifchumidifiertype.htm"
    },
    "IfcHygroscopicMaterialProperties": {
        "attributes": {
            "IsothermalMoistureCapacity": "Based on water vapor density, usually measured in [m3/ kg].",
            "LowerVaporResistanceFactor": "The vapor permeability relationship of air/material (typically value > 1), measured in low relative humidity (typically in 0/50 % RH).",
            "MoistureDiffusivity": "Usually measured in [m3/s].",
            "UpperVaporResistanceFactor": "The vapor permeability relationship of air/material (typically value > 1), measured in high relative humidity (typically in 95/50 % RH).",
            "VaporPermeability": "Usually measured in [kg/s m Pa]."
        },
        "description": "A container class with material hygroscopic properties defined in IFC specification.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifchygroscopicmaterialproperties.htm"
    },
    "IfcIShapeProfileDef": {
        "attributes": {
            "FilletRadius": "The fillet between the web and the flange, if not given, zero is assumed.",
            "FlangeThickness": "Flange thickness of the I-shape. Both, the upper and the lower flanges have the same thickness and they are centred on the y-axis of the position coordinate system.",
            "OverallDepth": "Total extent of the depth, defined parallel to the y axis of the position coordinate system.",
            "OverallWidth": "Total extent of the width, defined parallel to the x axis of the position coordinate system.",
            "WebThickness": "Thickness of the web of the I-shape. The web is centred on the x-axis and the y-axis of the position coordinate system."
        },
        "description": "Definition from IAI: The IfcIShapeProfileDef defines a section profile that provides the defining parameters of a symmetrical 'I' section to be used by the swept surface geometry or the swept area solid. The I-shape profile has values for its overall depth, width and its web and flange thickness. Additionally a fillet radius may be given. It represents a I-section that is symmetrical about its major and minor axes; and that has both top and bottom flanges being equal and centred on the web.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcishapeprofiledef.htm"
    },
    "IfcImageTexture": {
        "attributes": {
            "UrlReference": ""
        },
        "description": "Definition from IAI: An IfcImageTexture provides a 2-dimensional distribution of the lighting parameters of a surface onto which it is mapped.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcimagetexture.htm"
    },
    "IfcInventory": {
        "attributes": {
            "CurrentValue": "An estimate of the current cost value of the inventory.",
            "InventoryType": "A list of the types of inventories from which that required may be selected.",
            "Jurisdiction": "The organizational unit to which the inventory is applicable.",
            "LastUpdateDate": "The date on which the last update of the inventory was carried out.",
            "OriginalValue": "An estimate of the original cost value of the inventory.",
            "ResponsiblePersons": "Persons who are responsible for the inventory."
        },
        "description": "An IfcInventory is a list of items within an enterprise.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcinventory.htm"
    },
    "IfcIrregularTimeSeries": {
        "attributes": {
            "Values": "The collection of time series values."
        },
        "description": "In an irregular time series, unpredictable bursts of data arrive at unspecified points in time, or most time stamps cannot be characterized by a repeating pattern.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifcirregulartimeseries.htm"
    },
    "IfcIrregularTimeSeriesValue": {
        "attributes": {
            "ListValues": "A list of time-series values. At least one value is required.",
            "TimeStamp": "The specification of the time point."
        },
        "description": "The IfcIrregularTimeSeriesValue describes a value (or set of values) at a particular time point.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifcirregulartimeseriesvalue.htm"
    },
    "IfcJunctionBoxType": {
        "description": "An IfcJunctionBoxType defines a particular type of junction box which is a housing inside which cables from electrical components are connected electrically.",
        "predefined_types": {
            "NOTDEFINED": "Undefined type.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcjunctionboxtype.htm"
    },
    "IfcLShapeProfileDef": {
        "attributes": {
            "CentreOfGravityInX": "Location of centre of gravity along the x axis measured from the center of the bounding box.",
            "CentreOfGravityInY": "Location of centre of gravity along the Y axis measured from the center of the bounding box.",
            "Depth": "Leg length, see illustration above (= h).",
            "EdgeRadius": "Edge radius according the above illustration (= r2). If it is not given, zero is assumed.",
            "FilletRadius": "Fillet radius according the above illustration (= r1). If it is not given, zero is assumed.",
            "LegSlope": "Slope of leg of the profile. If it is not given, zero is assumed.",
            "Thickness": "Constant wall thickness of profile, see illustration above (= ts).",
            "Width": "Leg length, see illustration above (= b). If not given, the value of the Depth attribute is applied to Width."
        },
        "description": "Definition from IAI: The IfcLShapeProfileDef defines a section profile that provides the defining parameters of an L-shaped section (equilateral L profiles are also covered by this entity) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The shorter leg has the same direction as the positive x-axis, the longer or equal leg the same as the positive y-axis. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifclshapeprofiledef.htm"
    },
    "IfcLaborResource": {
        "attributes": {
            "SkillSet": "The skill set required for this type of labor."
        },
        "description": "An IfcLaborResource is used in construction with particular skills or crafts required to perform certain types of construction or management related work.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifclaborresource.htm"
    },
    "IfcLampType": {
        "description": "An IfcLampType is a type of device that is designed to emit light.",
        "predefined_types": {
            "COMPACTFLUORESCENT": "A fluorescent lamp having a compact form factor produced by shaping the tube.",
            "FLUORESCENT": "A typically tubular discharge lamp in which most of the light is emitted by one or several layers of phosphors excited by ultraviolet radiation from the discharge.",
            "HIGHPRESSUREMERCURY": "A discharge lamp in which most of the light is emitted by exciting mercury at high pressure.",
            "HIGHPRESSURESODIUM": "A discharge lamp in which most of the light is emitted by exciting sodium at high pressure.",
            "METALHALIDE": "A discharge lamp in which most of the light is emitted by exciting a metal halide.",
            "NOTDEFINED": "Undefined type.",
            "TUNGSTENFILAMENT": "A lamp that emits light by passing an electrical current through a tungsten wire filament in a near vacuum.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifclamptype.htm"
    },
    "IfcLibraryInformation": {
        "attributes": {
            "LibraryReference": "Information on the library being referenced.",
            "Name": "The name which is used to identify the library.",
            "Publisher": "Information of the organization that acts as the library publisher.",
            "Version": "Identifier for the library version used for reference.",
            "VersionDate": "Date of the referenced version of the library."
        },
        "description": "An IfcLibraryInformation is a class that describes a library where a library is a structured store of information, normally organized in a manner which allows information lookup through an index or reference value. IfcLibraryInformation provides the library name and optional version, version date and publisher attributes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifclibraryinformation.htm"
    },
    "IfcLibraryReference": {
        "attributes": {
            "ReferenceIntoLibrary": "The library information that is being referenced."
        },
        "description": "An IfcLibraryReference is a reference into a library of information by location (as an URL). It also provides an optional inherited ItemReference key to allow more specific references to library sections or tables, and the inherited Name attribute allows for a human interpretable identification of the library item. Also, general information on the external library can be given through IfcLibraryInformation, accessed by ReferenceIntoLibrary.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcexternalreferenceresource/lexical/ifclibraryreference.htm"
    },
    "IfcLightDistributionData": {
        "attributes": {
            "LuminousIntensity": "The luminous intensity distribution measure for this pair of main and secondary plane angles according to the light distribution curve chosen.",
            "MainPlaneAngle": "The main plane angle (A, B or C angles, according to the light distribution curve chosen).",
            "SecondaryPlaneAngle": "The list of secondary plane angles (the \u03b1, \u03b2 or \u03b3 angles) according to the light distribution curve chosen.  > NOTE: The _SecondaryPlaneAngle_ and _LuminousIntensity_ lists are corresponding lists."
        },
        "description": "The IfcLightDistributionData defines the luminous intensity of a light source given at a particular main plane angle. It is based on some standardized light distribution curves, the MainPlaneAngle is either the",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightdistributiondata.htm"
    },
    "IfcLightFixtureType": {
        "description": "An IfcLightFixtureType is a container type that is designed for the purpose of housing one or more lamps and the devices that control, restrict or vary their emission.",
        "predefined_types": {
            "DIRECTIONSOURCE": "A light fixture that is considered to have a length or surface area from which it emits light in a direction. A light fixture containing one or more fluorescent lamps is an example of a direction source.",
            "NOTDEFINED": "Undefined type.",
            "POINTSOURCE": "A light fixture that is considered to have negligible area and that emit light with approximately equal intensity in all directions.  A light fixture containing a tungsten, halogen or similar bulb is an example of a point source.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifclightfixturetype.htm"
    },
    "IfcLightIntensityDistribution": {
        "attributes": {
            "DistributionData": "Light distribution data applied to the light source. It is defined by a list of main plane angles (B or C according to the light distribution curve chosen) that includes (for each B or C angle) a second list of secondary plane angles (the \u03b2 or \u03b3 angles) and the according luminous intensity distribution measures.",
            "LightDistributionCurve": "Standardized  light distribution curve used to define the luminous intensity of the light in all directions."
        },
        "description": "The IfcLightIntensityDistribution defines the the luminous intensity of a light source that changes according to the direction of the ray. It is based on some standardized light distribution curves, which are defined by the LightDistributionCurve attribute.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightintensitydistribution.htm"
    },
    "IfcLightSource": {
        "attributes": {
            "AmbientIntensity": "Definition from VRML97 - ISO/IEC 14772-1:1997: The ambientIntensity specifies the intensity of the ambient emission from the light. Light intensity may range from 0.0 (no light emission) to 1.0 (full intensity).",
            "Intensity": "Definition from VRML97 - ISO/IEC 14772-1:1997: The intensity field specifies the brightness of the direct emission from the ligth. Light intensity may range from 0.0 (no light emission) to 1.0 (full intensity).",
            "LightColour": "Definition from ISO/CD 10303-46:1992: Based on the current lighting model, the colour of the light to be used for shading. Definition from VRML97 - ISO/IEC 14772-1:1997: The color field specifies the spectral color properties of both the direct and ambient light emission as an RGB value.",
            "Name": "The name given to the light source in presentation."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The light source entity is determined by the reflectance specified in the surface style rendering. Lighting is applied on a surface by surface basis: no interactions between surfaces such as shadows or reflections are defined.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightsource.htm"
    },
    "IfcLightSourceAmbient": {
        "description": "Definition from ISO/CD 10303-46:1992: The light source ambient entity is a subtype of light source. It lights a surface independent of the surface's orientation and position.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightsourceambient.htm"
    },
    "IfcLightSourceDirectional": {
        "attributes": {
            "Orientation": "Definition from ISO/CD 10303-46:1992: This direction is the direction of the light source. Definition from VRML97 - ISO/IEC 14772-1:1997: The direction field specifies the direction vector of the illumination emanating from the light source in the local coordinate system. Light is emitted along parallel rays from an infinite distance away."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The light source directional is a subtype of light source. This entity has a light source direction. With a conceptual origin at infinity, all the rays of the light are parallel to this direction. This kind of light source lights a surface based on the surface's orientation, but not position.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightsourcedirectional.htm"
    },
    "IfcLightSourceGoniometric": {
        "attributes": {
            "ColourAppearance": "Artificial light sources are classified in terms of their color appearance. To the human eye they all appear to be white; the difference can only be detected by direct comparison. Visual performance is not directly affected by differences in color appearance.",
            "ColourTemperature": "The color temperature of any source of radiation is defined as the temperature (in Kelvin) of a black-body or Planckian radiator whose radiation has the same chromaticity as the source of radiation. Often the values are only approximate color temperatures as the black-body radiator cannot emit radiation of every chromaticity value. The color temperatures of the commonest artificial light sources range from less than 3000K (warm white) to 4000K (intermediate) and over 5000K (daylight).",
            "LightDistributionDataSource": "The data source from which light distribution data is obtained.",
            "LightEmissionSource": "Identifies the types of light emitter from which the type required may be set.",
            "LuminousFlux": "Luminous flux is a photometric measure of radiant flux, i.e. the volume of light emitted from a light source. Luminous flux is measured either for the interior as a whole or for a part of the interior (partial luminous flux for a solid angle). All other photometric parameters are derivatives of luminous flux. Luminous flux is measured in lumens (lm). The luminous flux is given as a nominal value for each lamp.",
            "Position": "The position of the light source. It is used to orientate the light distribution curves."
        },
        "description": "The IfcLightSourceGoniometric defines a light source for which exact lighting data is available. It specifies the type of a light emitter, defines the position and orientation of a light distribution curve and the data concerning lamp and photometric information.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightsourcegoniometric.htm"
    },
    "IfcLightSourcePositional": {
        "attributes": {
            "ConstantAttenuation": "Definition from ISO/CD 10303-46:1992: This real indicates the value of the attenuation in the lighting equation that is constant.",
            "DistanceAttenuation": "Definition from ISO/CD 10303-46:1992: This real indicates the value of the attenuation in the lighting equation that proportional to the distance from the light source.",
            "Position": "Definition from ISO/CD 10303-46:1992: The Cartesian point indicates the position of the light source. Definition from VRML97 - ISO/IEC 14772-1:1997: A Point light node illuminates geometry within radius of its location.",
            "QuadricAttenuation": "Definition from the IAI: This real indicates the value of the attenuation in the lighting equation that proportional to the square value of the distance from the light source.",
            "Radius": "The maximum distance from the light source for a surface still to be illuminated. Definition from VRML97 - ISO/IEC 14772-1:1997: A Point light node illuminates geometry within radius of its location."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The light source positional entity is a subtype of light source. This entity has a light source position and attenuation coefficients. A positional light source affects a surface based on the surface's orientation and position.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightsourcepositional.htm"
    },
    "IfcLightSourceSpot": {
        "attributes": {
            "BeamWidthAngle": "Definition from VRML97 - ISO/IEC 14772-1:1997: The beamWidth field specifies an inner solid angle in which the light source emits light at uniform full intensity. The light source's emission intensity drops off from the inner solid angle (beamWidthAngle) to the outer solid angle (spreadAngle).",
            "ConcentrationExponent": "Definition from ISO/CD 10303-46:1992: This real is the exponent on the cosine of the angle between the line that starts at the position of the spot light source and is in the direction of the orientation of the spot light source and a line that starts at the position of the spot light source and goes through a point on the surface being shaded. NOTE: This attribute does not exists in ISO/IEC 14772-1:1997.",
            "Orientation": "Definition from ISO/CD 10303-46:1992: This is the direction of the axis of the cone of the light source specified in the coordinate space of the representation being projected.. Definition from VRML97 - ISO/IEC 14772-1:1997: The direction field specifies the direction vector of the light's central axis defined in the local coordinate system.",
            "SpreadAngle": "Definition from ISO/CD 10303-46:1992: This planar angle measure is the angle between the line that starts at the position of the spot light source and is in the direction of the spot light source and any line on the boundary of the cone of influence. Definition from VRML97 - ISO/IEC 14772-1:1997: The cutOffAngle (name of spread angle in VRML) field specifies the outer bound of the solid angle. The light source does not emit light outside of this solid angle."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The light source spot entity is a subtype of light source. Spot light source entities have a light source colour, position, direction, attenuation coefficients, concentration exponent, and spread angle. If a point lies outside the cone of influence of a light source of this type as determined by the light source position, direction and spread angle its colour is not affected by that light source.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifclightsourcespot.htm"
    },
    "IfcLine": {
        "attributes": {
            "Dir": "The direction of the line, the magnitude and units of Dir affect the parameterization of the line.",
            "Pnt": "The location of the line."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A line is an unbounded curve with constant tangent direction. A line is defined by a point and a direction. The positive direction of the line is in the direction of the Dir vector. The line is parameterized as follows:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcline.htm"
    },
    "IfcLinearDimension": {
        "description": "The linear dimension is a draughting callout that presents the length (or distance) between two points along a linear curve. It consists of a dimension curve and optionally one or two projection curves.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifclineardimension.htm"
    },
    "IfcLocalPlacement": {
        "attributes": {
            "PlacementRelTo": "Reference to Object that provides the relative placement by its local coordinate system. If it is omitted, then the local placement is given to the WCS, established by the geometric representation context.",
            "RelativePlacement": "Geometric placement that defines the transformation from the related coordinate system into the relating. The placement can be either 2D or 3D, depending on the dimension count of the coordinate system."
        },
        "description": "Definition from IFC: The IfcLocalPlacement defines the relative placement of a product in relation to the placement of another product or the absolute placement of a product within the geometric representation context of the project.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifclocalplacement.htm"
    },
    "IfcLocalTime": {
        "attributes": {
            "DaylightSavingOffset": "The offset of daylight saving time from basis time.",
            "HourComponent": "The number of hours of the local time.",
            "MinuteComponent": "The number of minutes of the local time.",
            "SecondComponent": "The number of seconds of the local time.",
            "Zone": "The relationship of the local time to coordinated universal time."
        },
        "description": "Definition from ISO/CD 10303-41:1992: A moment of occurrence measured by hour, minute, and second. It represents one instant of time on a 24 hour clock.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcdatetimeresource/lexical/ifclocaltime.htm"
    },
    "IfcLoop": {
        "description": "Definition from ISO/CD 10303-42:1992: A loop is a topological entity constructed from a single vertex, or by stringing together connected (oriented) edges, or linear segments beginning and ending at the same vertex. It is typically used to bound a face lying on a surface. A loop has dimensionality of 0 or 1. The domain of a 0-dimensional loop is a single point. The domain of a 1-dimensional loop is a connected, oriented curve, but need not to be manifold. As the loop is a circle, the location of its beginning/ending point is arbitrary. The domain of the loop includes its bounds, an 0 \u2264 \u039e < \u221e.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcloop.htm"
    },
    "IfcManifoldSolidBrep": {
        "attributes": {
            "Outer": "A closed shell defining the exterior boundary of the solid. The shell normal shall point away from the interior of the solid."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A manifold solid B-rep is a finite, arcwise connected volume bounded by one or more surfaces, each of which is a connected, oriented, finite, closed 2-manifold. There is no restriction on the genus of the volume, nor on the number of voids within the volume.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcmanifoldsolidbrep.htm"
    },
    "IfcMappedItem": {
        "attributes": {
            "MappingSource": "A representation map that is the source of the mapped item. It can be seen as a block (or cell or marco) definition.",
            "MappingTarget": "A representation item that is the target onto which the mapping source is mapped. It is constraint to be a Cartesian transformation operator."
        },
        "description": "Definition from ISO/CD 10303-43:1992: A mapped item is the use of an existing representation (the mapping source - mapped representation) as a representation item in a second representation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcmappeditem.htm"
    },
    "IfcMaterial": {
        "attributes": {
            "ClassifiedAs": "Reference to the relationship pointing to the classification(s) of the material.",
            "HasRepresentation": "Reference to the _IfcMaterialDefinitionRepresentation_ that provides presentation information to a representation common to this material in style definitions.",
            "Name": "Name of the material."
        },
        "description": "A homogeneous substance that can be used to form elements.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcmaterial.htm"
    },
    "IfcMaterialClassificationRelationship": {
        "attributes": {
            "ClassifiedMaterial": "Material being classified.",
            "MaterialClassifications": "The material classifications identifying the type of material."
        },
        "description": "Relationship assigning classifications to materials.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcmaterialclassificationrelationship.htm"
    },
    "IfcMaterialDefinitionRepresentation": {
        "attributes": {
            "RepresentedMaterial": "Reference to the material to which the representation applies."
        },
        "description": "The IfcMaterialDefinitionRepresentation defines presentation information relating to IfcMaterial. It allows for multiple presentations of the same material for different geometric representation contexts.  ",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcmaterialdefinitionrepresentation.htm"
    },
    "IfcMaterialLayer": {
        "attributes": {
            "IsVentilated": "Indication of whether the material layer represents an air layer (or cavity).  * set to TRUE if the material layer is an air gap and provides air exchange from the layer to the outside air. * set to UNKNOWN if the material layer is an air gap and does not provide air exchange (or when this information about air exchange of the air gap is not available). * set to FALSE if the material layer is a solid material layer (the default).",
            "LayerThickness": "The thickness of the layer (dimension measured along the local x-axis of Mls LCS, in positive direction).",
            "Material": "Optional reference to the material from which the layer is constructed. Note, that if this value is not given, it does not denote a layer with no material (an air gap), it only means that the material is not specified at that point.",
            "ToMaterialLayerSet": "Reference to the material layer set, in which the material layer is included."
        },
        "description": "A single and identifiable part of an element which is constructed of a number of layers (one or more).  Each IfcMaterialLayer is located relative to the referencing IfcMaterialLayerSet.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcmateriallayer.htm"
    },
    "IfcMaterialLayerSet": {
        "attributes": {
            "LayerSetName": "The name by which the material layer set is known.",
            "MaterialLayers": "Identification of the layers from which the material layer set is composed.",
            "TotalThickness": "Total thickness of the material layer set is derived from the function IfcMlsTotalThickness. IfcMlsTotalThickness(SELF)"
        },
        "description": "Definition from IAI: A designation by which materials of an element constructed of a number of material layers is known and through which the relative positioning of individual layers can be expressed.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcmateriallayerset.htm"
    },
    "IfcMaterialLayerSetUsage": {
        "attributes": {
            "DirectionSense": "Denotion whether the layer set is oriented in positive or negative sense relative to the material layer set base. The meaning of \"positive\" and \"negative\" needs to be established in the geometry use definitions. See examples at _IfcMaterialLayerSetUsage_ for a guideline as well.",
            "ForLayerSet": "The _IfcMaterialLayerSet_ set to which the usage is applied.",
            "LayerSetDirection": "Orientation of the layer set relative to element reference geometry. The meaning of the value of this attribute shall be specified in the geometry use section for each element. For extruded shape representation, direction can be given along the extrusion path (e.g. for slabs) or perpendicular to it (e.g. for walls). > NOTE  the LayerSetDirection for IfcWallStandardCase shall be AXIS2 (i.e. the y-axis) and for standard IfcSlab it shall be AXIS3 (i.e. the z-axis).",
            "OffsetFromReferenceLine": "Offset of the material layer set base line (MlsBase) from reference geometry (line or plane). The offset can be positive or negative, unless restricted for a particular building element type in its use definition or by implementer agreement. The reference geometry for each relevant subtype of _IfcElement_ is defined in use definition for the element. Examples are given in the use definition of _IfcMaterialLayerSetUsage_."
        },
        "description": "Definition from IAI: Determines the usage of IfcMaterialLayerSet in terms of its location and orientation relative to the associated element geometry. The location of material layer set shall be compatible with the building element geometry (i.e. material layers shall fit inside the element geometry). The rules to ensure the compatibility depend on the type of the building element.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcmateriallayersetusage.htm"
    },
    "IfcMaterialList": {
        "attributes": {
            "Materials": "Materials used in a composition of substances."
        },
        "description": "A list of the different materials that are used in an element.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialresource/lexical/ifcmateriallist.htm"
    },
    "IfcMaterialProperties": {
        "attributes": {
            "Material": "Reference to the material to which the set of properties is assigned."
        },
        "description": "Abstract supertype of all container classes with material properties, both those defined in IFC specification and those defined by users as extended material properties.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcmaterialproperties.htm"
    },
    "IfcMeasureWithUnit": {
        "attributes": {
            "UnitComponent": "The unit in which the physical quantity is expressed.",
            "ValueComponent": "The value of the physical quantity when expressed in the specified units."
        },
        "description": "Definition from ISO/CD 10303-41:1992: A measure with unit is the specification of a physical quantity as defined in ISO 31 (clause 2).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmeasurewithunit.htm"
    },
    "IfcMechanicalConcreteMaterialProperties": {
        "attributes": {
            "AdmixturesDescription": "Description of the admixtures added to the concrete mix.",
            "CompressiveStrength": "The compressive strength of the concrete.",
            "MaxAggregateSize": "The maximum aggregate size of the concrete.",
            "ProtectivePoreRatio": "The protective pore ratio indicating the frost-resistance of the concrete.",
            "WaterImpermeability": "Description of the water impermeability denoting the water repelling properties.",
            "Workability": "Description of the workability of the fresh concrete defined according to local standards."
        },
        "description": "",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcmechanicalconcretematerialproperties.htm"
    },
    "IfcMechanicalFastener": {
        "attributes": {
            "NominalDiameter": "The nominal diameter describing the cross-section size of the fastener.",
            "NominalLength": "The nominal length describing the longitudinal dimensions of the fastener."
        },
        "description": "Fasteners connecting building elements mechanically.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcmechanicalfastener.htm"
    },
    "IfcMechanicalFastenerType": {
        "description": "The element type (IfcMechanicalFastenerType) defines a list of commonly shared property set definitions of a fastener and an optional set of product representations. It is used to define mechanical fasteners mainly within structural and building services domains (i.e. the specific type information common to all occurrences of that type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcmechanicalfastenertype.htm"
    },
    "IfcMechanicalMaterialProperties": {
        "attributes": {
            "DynamicViscosity": "A measure of the viscous resistance of the material.",
            "PoissonRatio": "A measure of the lateral deformations in the elastic range.",
            "ShearModulus": "A measure of the shear modulus of elasticity of the material.",
            "ThermalExpansionCoefficient": "A measure of the expansion coefficient for warming up the material about one Kelvin.",
            "YoungModulus": "A measure of the Young's modulus of elasticity of the material."
        },
        "description": "This is a collection of mechanical material properties normally used for structural analysis purpose. It contains all properties which are independent of the actual material type.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcmechanicalmaterialproperties.htm"
    },
    "IfcMechanicalSteelMaterialProperties": {
        "attributes": {
            "HardeningModule": "A measure of the hardening module of the material (slope of stress versus strain curve after yield range).",
            "PlasticStrain": "A measure of the permanent displacement, as in slip or twinning, which remains after the stress has been removed. Currently applied to a strain of 0.2% proportional stress of the material.",
            "ProportionalStress": "A measure of the proportional stress of the material. It describes the stress before the first plastic deformation occurs and is commonly measured at a deformation of 0.01%.",
            "Relaxations": "Measures of decrease in stress over long time intervals resulting from plastic flow. Different relaxation values for different initial stress levels for a material may be given.",
            "UltimateStrain": "A measure of the (engineering) strain at the state of ultimate stress of the material.",
            "UltimateStress": "A measure of the ultimate stress of the material.",
            "YieldStress": "A measure of the yield stress (or characteristic 0.2 percent proof stress) of the material."
        },
        "description": "This is a collection of mechanical properties related to steel (or other metallic and isotropic) materials.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcmechanicalsteelmaterialproperties.htm"
    },
    "IfcMember": {
        "description": "An IfcMember is a structural member designed to carry loads between or beyond points of support. It is not required to be load bearing. The location of the member (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to IfcBeam and IfcColumn).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcmember.htm"
    },
    "IfcMemberType": {
        "description": "The element type (IfcMemberType) defines a list of commonly shared property set definitions of a structural member and an optional set of product representations. It is used to define a structural member specification (i.e. the specific product information that is common to all occurrences of that product type).",
        "predefined_types": {
            "BRACE": "A linear element (usually sloped) often used for bracing of a girder or truss.",
            "CHORD": "Upper or lower longitudinal member of a truss, used horizontally or sloped.",
            "COLLAR": "A linear element (usually used horizontally) within a roof structure to connect rafters and posts.",
            "MEMBER": "A linear element within a girder or truss with no further meaning.",
            "MULLION": "A linear element within a curtain wall system to connect two (or more) panels.",
            "NOTDEFINED": "Undefined linear element.",
            "PLATE": "A&nbsp;linear continuous horizontal element in wall framing, such as a head piece or a sole plate.",
            "POST": "A linear member (usually used vertically) within a roof structure to support purlins.",
            "PURLIN": "A linear element (usually used horizontally) within a roof structure to support rafters.",
            "RAFTER": "A linear elements used to support roof slabs or roof covering, usually used with slope.",
            "STRINGER": "A linear element used to support stair or ramp flights, usually used with slope.",
            "STRUT": "A linear element often used within a girder or truss.",
            "STUD": "Vertical element in wall framing.",
            "USERDEFINED": "User-defined linear element."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcmembertype.htm"
    },
    "IfcMetric": {
        "attributes": {
            "Benchmark": "Enumeration that identifies the type of benchmark data.",
            "DataValue": "Value with data type defined by the DataType enumeration.",
            "ValueSource": "Reference source for data values."
        },
        "description": "An IfcMetric is used to capture quantitative resultant metrics that can be applied to objectives.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcmetric.htm"
    },
    "IfcMonetaryUnit": {
        "attributes": {
            "Currency": "The international enumeration name of the currency."
        },
        "description": "IfcMonetaryUnit is a unit to define currency for money.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcmonetaryunit.htm"
    },
    "IfcMotorConnectionType": {
        "description": "An IfcMotorConnectionType provides the means for connecting a motor as the driving device to the driven device.",
        "predefined_types": {
            "BELTDRIVE": "An indirect connection made through the medium of a shaped, flexible continuous loop.",
            "COUPLING": "An indirect connection made through the medium of the viscosity of a fluid.",
            "DIRECTDRIVE": "A direct, physical connection made between the motor and the driven device.",
            "NOTDEFINED": "Undefined type.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcmotorconnectiontype.htm"
    },
    "IfcMove": {
        "attributes": {
            "MoveFrom": "The place from which actors and their associated equipment are moving.",
            "MoveTo": "The place to which actors and their associated equipment are moving.",
            "PunchList": "A list of points concerning a move that require attention."
        },
        "description": "An IfcMove is an activity that moves people, groups within an organization or complete organizations together with their associated furniture and equipment from one place to another. The objects to be moved, normally people, equipment, and furniture, are assigned by the IfcRelAssignsToProcess relationship.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcmove.htm"
    },
    "IfcNamedUnit": {
        "attributes": {
            "Dimensions": "The dimensional exponents of the SI base units by which the named unit is defined.",
            "UnitType": "The type of the unit."
        },
        "description": "Definition from ISO/CD 10303-41:1992: A named unit is a unit quantity associated with the word, or group of words, by which the unit is identified.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcnamedunit.htm"
    },
    "IfcObject": {
        "attributes": {
            "IsDefinedBy": "Set of relationships to type or property (statically or dynamically defined) information that further define the object. In case of type information, the associated _IfcTypeObject_ contains the specific information (or type, or style), that is common to all instances of _IfcObject_ referring to the same type.",
            "ObjectType": "The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute _PredefinedType_ is set to USERDEFINED."
        },
        "description": "An IfcObject is the generalization of any semantically treated thing or process. Objects are things as they appear - i.e. occurrences.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcobject.htm"
    },
    "IfcObjectDefinition": {
        "attributes": {
            "Decomposes": "References to the decomposition relationship, that allows this object to be a part of the decomposition. An object can only be part of a single decomposition (to allow hierarchical strutures only).",
            "HasAssignments": "Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups.",
            "HasAssociations": "Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification.",
            "IsDecomposedBy": "Reference to the decomposition relationship, that allows this object to be the composition of other objects. An object can be decomposed by several other objects."
        },
        "description": "Definition from IAI: An IfcObjectDefinition is the generalization of any semantically treated thing or process, either being a type or an occurrences. Object defintions can be named, using the inherited Name attribute, which should be a user recognizable label for the object occurrence. Further explanations to the object can be given using the inherited Description attribute. ",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcobjectdefinition.htm"
    },
    "IfcObjectPlacement": {
        "attributes": {
            "PlacesObject": "The _IfcObjectPlacement_ shall be used to provide a placement and an object coordinate system for a single instance of _IfcProduct_.",
            "ReferencedByPlacements": "Placements that are given relative to this placement of an object."
        },
        "description": "Abstract supertype for the special types defining the object coordinate system. The IfcObjectPlacement has to be provided for each product that has a shape representation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcobjectplacement.htm"
    },
    "IfcObjective": {
        "attributes": {
            "BenchmarkValues": "A list of any benchmark values used for comparison purposes.",
            "ObjectiveQualifier": "Enumeration that qualifies the type of objective constraint.",
            "ResultValues": "A list of any resultant values used for comparison purposes.",
            "UserDefinedQualifier": "A user defined value that qualifies the type of objective constraint when ObjectiveQualifier attribute of type _IfcObjectiveEnum_ has value USERDEFINED."
        },
        "description": "An IfcObjective captures qualitative information for an objective-based constraint.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcobjective.htm"
    },
    "IfcOccupant": {
        "description": "An_IfcOccupant_ is a type of actor that defines the form of occupancy of a property.",
        "predefined_types": {
            "ASSIGNEE": "Actor receiving the assignment of a property agreement from an assignor.",
            "ASSIGNOR": "Actor assigning a property agreement to an assignor.",
            "LESSEE": "Actor receiving the lease of a property from a lessor.",
            "LESSOR": "Actor leasing a property to a lessee.",
            "LETTINGAGENT": "Actor participating in a property agreement on behalf of an owner, lessor or assignor.",
            "NOTDEFINED": "Undefined type.",
            "OWNER": "Actor that owns a property.",
            "TENANT": "Actor renting the use of a property fro a period of time.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcoccupant.htm"
    },
    "IfcOffsetCurve2D": {
        "attributes": {
            "BasisCurve": "The curve that is being offset.",
            "Distance": "The distance of the offset curve from the basis curve. distance may be positive, negative or zero. A positive value of distance defines an offset in the direction which is normal to the curve in the sense of an anti-clockwise rotation through 90 degrees from the tangent vector T at the given point. (This is in the direction of orthogonal complement(T).)",
            "SelfIntersect": "An indication of whether the offset curve self-intersects; this is for information only."
        },
        "description": "Definition from ISO/CD 10303-42:1992: An offset curve 2d (IfcOffsetCurve2d) is a curve at a constant distance from a basis curve in two-dimensional space. This entity defines a simple plane-offset curve by offsetting by distance along the normal to basis curve in the plane of basis curve. The underlying curve shall have a well-defined tangent direction at every point. In the case of a composite curve, the transition code between each segment shall be cont same gradient or cont same gradient same curvature.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcoffsetcurve2d.htm"
    },
    "IfcOffsetCurve3D": {
        "attributes": {
            "BasisCurve": "The curve that is being offset.",
            "Distance": "The distance of the offset curve from the basis curve. The distance may be positive, negative or zero.",
            "RefDirection": "The direction used to define the direction of the offset curve 3d from the basis curve.",
            "SelfIntersect": "An indication of whether the offset curve self-intersects, this is for information only."
        },
        "description": "Definition from ISO/CD 10303-42:1992: An offset curve 3d is a curve at a constant distance from a basis curve in three-dimensional space. The underlying curve shall have a well-defined tangent direction at every point. In the case of a composite curve the transition code between each segment shall be cont same gradient or cont same gradient same curvature. The offset curve at any point (parameter) on the basis curve is in the direction V x T where V is the fixed reference direction and T is the unit tangent to the basis curve. For the offset direction to be well defined, T shall not at any point of the curve be in the same, or opposite, direction as V.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcoffsetcurve3d.htm"
    },
    "IfcOneDirectionRepeatFactor": {
        "attributes": {
            "RepeatFactor": "A vector which specifies the relative positioning of hatch lines."
        },
        "description": "Definition from ISO/CD 10303-46:1992: A one time repeat factor is a vector used in the fill area style hatching and fill area style tiles entities for determining the origin of the repeated hatch line relative to the origin of the previous hatch line, Given the initial position of any hatch line, the one direction repeat factor determines two new positions according to the equation:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifconedirectionrepeatfactor.htm"
    },
    "IfcOpenShell": {
        "description": "Definition from ISO/CD 10303-42:1992: An open shell is a shell of the dimensionality 2. Its domain, if present, is a finite, connected, oriented, 2-manifold with boundary, but is not a closed surface. It can be thought of as a closed shell with one or more holes punched in it. The domain of an open shell satisfies 0 < \u039e < 1. An open shell is functionally more general than a face because its domain can have handles.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcopenshell.htm"
    },
    "IfcOpeningElement": {
        "attributes": {
            "HasFillings": "Reference to the Filling Relationship that is used to assign Elements as Fillings for this Opening Element. The Opening Element can be filled with zero-to-many Elements."
        },
        "description": "The opening element stands for opening, recess or chase, all reflecting voids. It represents a void within any element that has physical manifestation. Openings must be handled by all sectors and disciplines in AEC/FM industry, therefore the interoperability for opening elements is provided at this high level.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcopeningelement.htm"
    },
    "IfcOpticalMaterialProperties": {
        "attributes": {
            "SolarReflectanceBack": "Reflectance at normal incidence (solar): back side. Defines the fraction of the solar ray that is reflected and not transmitted when the ray passes from one medium into another, at the \"back\" side of the other material, perpendicular to the surface. Dependent on material and surface characteristics.",
            "SolarReflectanceFront": "Reflectance at normal incidence (solar): front side. Defines the fraction of the solar ray that is reflected and not transmitted when the ray passes from one medium into another, at the \"front\" side of the other material, perpendicular to the surface. Dependent on material and surface characteristics.",
            "SolarTransmittance": "Transmittance at normal incidence (solar). Defines the fraction of solar radiation that passes through per unit area, perpendicular to the surface.",
            "ThermalIrEmissivityBack": "Thermal IR emissivity: back side. Defines the fraction of thermal energy emitted per unit area to \"blackbody\" at the same temperature, through the \"back\" side of the material.",
            "ThermalIrEmissivityFront": "Thermal IR emissivity: front side. Defines the fraction of thermal energy emitted per unit area to \"blackbody\" at the same temperature, through the \"front\" side of the material.",
            "ThermalIrTransmittance": "Thermal IR transmittance at normal incidence. Defines the fraction of thermal energy that passes through per unit area, perpendicular to the surface.",
            "VisibleReflectanceBack": "Reflectance at normal incidence (visible): back side. Defines the fraction of the solar ray in the visible spectrum that is reflected and not transmitted when the ray passes from one medium into another, at the \"back\" side of the other material, perpendicular to the surface. Dependent on material and surface characteristics.",
            "VisibleReflectanceFront": "Reflectance at normal incidence (visible): front side. Defines the fraction of the solar ray in the visible spectrum that is reflected and not transmitted when the ray passes from one medium into another, at the \"front\" side of the other material, perpendicular to the surface. Dependent on material and surface characteristics.",
            "VisibleTransmittance": "Transmittance at normal incidence (visible). Defines the fraction of the visible spectrum of solar radiation that passes through per unit area, perpendicular to the surface."
        },
        "description": "A container class with material optical properties defined in IFC specification.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcopticalmaterialproperties.htm"
    },
    "IfcOrderAction": {
        "attributes": {
            "ActionID": "A unique identifier assigned to an action on issue."
        },
        "description": "An IfcOrderAction is the point at which requests for work are received and processed within an organization.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcorderaction.htm"
    },
    "IfcOrganization": {
        "attributes": {
            "Addresses": "Postal and telecom addresses of an organization. > NOTE: There may be several addresses related to an organization.",
            "Description": "Text that relates the nature of the organization.",
            "Engages": "Inverse relationship to IfcPersonAndOrganization relationships in which IfcOrganization is engaged.",
            "Id": "Identification of the organization.",
            "IsRelatedBy": "The inverse relationship for relationship RelatedOrganizations of IfcOrganizationRelationship.",
            "Name": "The word, or group of words, by which the organization is referred to.",
            "Relates": "The inverse relationship for relationship RelatingOrganization of IfcOrganizationRelationship.",
            "Roles": "Roles played by the organization."
        },
        "description": "A named and structured grouping with a corporate identity.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcorganization.htm"
    },
    "IfcOrganizationRelationship": {
        "attributes": {
            "Description": "Text that relates the nature of the relationship.",
            "Name": "The word or group of words by which the relationship is referred to.",
            "RelatedOrganizations": "The other, possibly dependent, organizations which are the related parts of the relationship between organizations.",
            "RelatingOrganization": "Organization which is the relating part of the relationship between organizations."
        },
        "description": "IfcOrganizationRelationship establishes an association between one relating organization, and one or more related organizations.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcorganizationrelationship.htm"
    },
    "IfcOrientedEdge": {
        "attributes": {
            "EdgeElement": "Edge entity used to construct this oriented edge.",
            "EdgeEnd": "The end vertex of the oriented edge. It derives from the vertices of the edge element after taking account of the orientation. IfcBooleanChoose  (Orientation, EdgeElement.EdgeEnd, EdgeElement.EdgeStart)",
            "EdgeStart": "The start vertex of the oriented edge. It derives from the vertices of the edge element after taking account of the orientation. IfcBooleanChoose  (Orientation, EdgeElement.EdgeStart, EdgeElement.EdgeEnd)",
            "Orientation": "BOOLEAN, If TRUE the topological orientation as used coincides with the orientation from start vertex to end vertex of the edge element. If FALSE otherwise."
        },
        "description": "Definition from ISO/CD 10303-42:1992: An oriented edge is an edge constructed from another edge and contains a BOOLEAN direction flag to indicate whether or not the orientation of the constructed edge agrees with the orientation of the original edge. Except for perhaps orientation, the oriented edge is equivalent to the original edge.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcorientededge.htm"
    },
    "IfcOutletType": {
        "description": "An IfcOutletType defines a particular type of outlet which is a device installed at a point to receive an inserted plug.",
        "predefined_types": {
            "AUDIOVISUALOUTLET": "An outlet used for an audio or visual device.",
            "COMMUNICATIONSOUTLET": "An outlet used for connecting communications equipment.",
            "NOTDEFINED": "Undefined type.<",
            "POWEROUTLET": "An outlet used for connecting electrical devices requiring power.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcoutlettype.htm"
    },
    "IfcOwnerHistory": {
        "attributes": {
            "ChangeAction": "Enumeration that defines the actions associated with changes made to the object.",
            "CreationDate": "Time and date of creation.",
            "LastModifiedDate": "Date and Time at which the last modification occurred.",
            "LastModifyingApplication": "Application used to carry out the last modification.",
            "LastModifyingUser": "User who carried out the last modification.",
            "OwningApplication": "Direct reference to the application which currently \"Owns\" this object on behalf of the owning user, who uses this application. Note that IFC includes the concept of ownership transfer from one app to another and therefore distinguishes between the Owning Application and Creating Application.",
            "OwningUser": "Direct reference to the end user who currently \"owns\" this object. Note that IFC includes the concept of ownership transfer from one user to another and therefore distinguishes between the Owning User and Creating User.",
            "State": "Enumeration that defines the current access state of the object."
        },
        "description": "IfcOwnerHistory defines all history and identification related information. In order to provide fast access it is directly attached to all independent objects, relationships and properties.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcutilityresource/lexical/ifcownerhistory.htm"
    },
    "IfcParameterizedProfileDef": {
        "attributes": {
            "Position": "Position coordinate system of the parameterized profile definition."
        },
        "description": "The parameterized profile definition defines a 2D position coordinate system to which the parameters of the different profiles relate to. All profiles are defined centric to the origin of the position coordinate system, or more specific, the origin [0.,0.] shall be in the center of the bounding box ~~gravity~~ of the profile.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcparameterizedprofiledef.htm"
    },
    "IfcPath": {
        "attributes": {
            "EdgeList": "The list of oriented edges which are concatenated together to form this path."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A path is a topological entity consisting of an ordered collection of oriented edges, such that the edge start vertex of each edge coincides with the edge end of its predecessor. The path is ordered from the edge start of the first oriented edge to the edge end of the last edge. The BOOLEAN value sense in the oriented edge indicates whether the edge direction agrees with the direction of the path (TRUE) or is the opposite direction (FALSE).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcpath.htm"
    },
    "IfcPerformanceHistory": {
        "attributes": {
            "LifeCyclePhase": "Describes the applicable building life-cycle phase. Typical values should be DESIGNDEVELOPMENT, SCHEMATICDEVELOPMENT, CONSTRUCTIONDOCUMENT, CONSTRUCTION, ASBUILT, COMMISSIONING, OPERATION, etc."
        },
        "description": "The IfcPerformanceHistory is used to document the actual performance of an occurrence instance over time. In practice, performance-related data are generally not easy to obtain as they can originate from different sources (e.g. predicted, simulated, or measured) and occur during different stages of the building life-cycle. Such time-related data cover a large spectrum, including meteorological data, schedules, operational status measurements, trend reports, etc.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccontrolextension/lexical/ifcperformancehistory.htm"
    },
    "IfcPermeableCoveringProperties": {
        "attributes": {
            "FrameDepth": "Depth of panel frame (used to include the permeable covering), measured from front face to back face horizontally (i.e. perpendicular to the window or door (elevation) plane.",
            "FrameThickness": "Width of panel frame (used to include the permeable covering), measured from inside of panel (at permeable covering) to outside of panel (at lining), i.e. parallel to the window or door (elevation) plane.",
            "OperationType": "Types of permeable covering operations. Also used to assign standard symbolic presentations according to national building standards.",
            "PanelPosition": "Position of this permeable covering panel within the overall window or door type.",
            "ShapeAspectStyle": "Optional link to a shape aspect definition, which points to the part of the geometric representation of the window style, which is used to represent the permeable covering."
        },
        "description": "Definition from BS 6100: A permeable covering is a permeable cover for an opening which allows airflow .",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcarchitecturedomain/lexical/ifcpermeablecoveringproperties.htm"
    },
    "IfcPermit": {
        "attributes": {
            "PermitID": "A unique identifier assigned to a permit."
        },
        "description": "An IfcPermit is a document that allows permission to carry out actions in places and on artifacts where security or other access restrictions apply.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcfacilitiesmgmtdomain/lexical/ifcpermit.htm"
    },
    "IfcPerson": {
        "attributes": {
            "Addresses": "Postal and telecommunication addresses of a person. > NOTE - A person may have several addresses.",
            "EngagedIn": "The inverse relationship to IfcPersonAndOrganization relationships in which IfcPerson is engaged.",
            "FamilyName": "The name by which the family identity of the person may be recognized. > NOTE: Depending on geographical location and culture, family name may appear either as the first or last component of a name.",
            "GivenName": "The name by which a person is known within a family and by which he or she may be familiarly recognized. > NOTE: Depending on geographical location and culture, given name may appear either as the first or last component of a name.",
            "Id": "Identification of the person.",
            "MiddleNames": "Additional names given to a person that enable their identification apart from others who may have the same or similar family and given names. > NOTE: Middle names are not normally used in familiar communication but may be asserted to provide additional  identification of a particular person if necessary. They may be particularly useful in situations where the person concerned has a  family name that occurs commonly in the geographical region.",
            "PrefixTitles": "The word, or group of words, which specify the person's social and/or professional standing and appear before his/her names.",
            "Roles": "Roles played by the person.",
            "SuffixTitles": "The word, or group of words, which specify the person's social and/or professional standing and appear after his/her names."
        },
        "description": "Definition from ISO/CD 10303-41:1992: An individual human being.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcperson.htm"
    },
    "IfcPersonAndOrganization": {
        "attributes": {
            "Roles": "Roles played by the person within the context of an organization.",
            "TheOrganization": "The organization to which the person is related.",
            "ThePerson": "The person who is related to the organization."
        },
        "description": "Identification of a person within an organization.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcpersonandorganization.htm"
    },
    "IfcPhysicalComplexQuantity": {
        "attributes": {
            "Discrimination": "Identification of the discrimination by which this physical complex property is distinguished. Examples of discriminations are 'layer', 'steel bar diameter', etc.",
            "HasQuantities": "Set of physical quantities that are grouped by this complex physical quantity according to a given discrimination.",
            "Quality": "Additional indication of a quality of the quantities that are grouped under this physical complex quantity.",
            "Usage": "Additional indication of a usage type of the quantities that are grouped under this physical complex quantity."
        },
        "description": "The complex physical quantity, IfcPhysicalComplexQuantity, is an entity that holds a set of single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity), that all apply to a given component or aspect of the element.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcphysicalcomplexquantity.htm"
    },
    "IfcPhysicalQuantity": {
        "attributes": {
            "Description": "Further explanation that might be given to the quantity.",
            "Name": "Name of the element quantity or measure. The name attribute has to be made recognizable by further agreements.",
            "PartOfComplex": "Reference to a physical complex quantity in which the physical quantity may be contained."
        },
        "description": "The physical quantity, IfcPhysicalQuantity, is an abstract entity that holds a complex or simple quantity measure together with a semantic definition of the usage for the single or several measure value.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcphysicalquantity.htm"
    },
    "IfcPhysicalSimpleQuantity": {
        "attributes": {
            "Unit": "Optional assignment of a unit. If no unit is given, then the global unit assignment, as established at the IfcProject, applies to the quantity measures."
        },
        "description": "The physical quantity, IfcPhysicalSimpleQuantity, is an entity that holds a single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity) together with a semantic definition of the usage for the measure value.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcphysicalsimplequantity.htm"
    },
    "IfcPile": {
        "attributes": {
            "ConstructionType": "General designator for how the pile is constructed."
        },
        "description": "A slender timber, concrete, or steel structural element, driven, jetted, or otherwise embedded on end in the ground for the purpose of supporting a load.",
        "predefined_types": {
            "COHESION": "A cohesion pile.",
            "FRICTION": "A friction pile.",
            "NOTDEFINED": "The type of pile function is not defined.",
            "SUPPORT": "A support pile.",
            "USERDEFINED": "The type of pile function is user defined."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcpile.htm"
    },
    "IfcPipeFittingType": {
        "description": "The element type IfcPipeFittingType defines a list of commonly shared property set definitions of a pipe fitting and an optional set of product representations. It is used to define a pipe fitting specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "BEND": "A fitting with typically two ports used to change the direction of flow between connected elements.",
            "CONNECTOR": "Connector fitting, typically used to join two ports together within a flow distribution system (e.g., a coupling used to join two pipe segments).",
            "ENTRY": "Entry fitting, typically unconnected at one port and connected to a flow distribution system at the other (e.g., a breeching inlet).",
            "EXIT": "Exit fitting, typically unconnected at one port and connected to a flow distribution system at the other (e.g., a hose bibb).",
            "JUNCTION": "A fitting with typically more than two ports used to redistribute flow among the ports and/or to change the direction of flow between connected elements (e.g, tee, cross, wye, etc.).",
            "NOTDEFINED": "Undefined fitting.",
            "OBSTRUCTION": "A fitting with typically two ports used to obstruct or restrict flow between the connected elements (e.g., screen, perforated plate, etc.).",
            "TRANSITION": "A fitting with typically two ports having different shapes or sizes. Can also be used to change the direction of flow between connected elements.",
            "USERDEFINED": "User-defined fitting."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcpipefittingtype.htm"
    },
    "IfcPipeSegmentType": {
        "description": "The element type IfcPipeSegmentType defines a list of commonly shared property set definitions of a pipe segment and an optional set of product representations. It is used to define a pipe segment specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "FLEXIBLESEGMENT": "A flexible segment is a continuous non-linear segment of pipe that can be deformed and change the direction of flow.",
            "GUTTER": "A gutter segment is a continuous open-channel segment of pipe.",
            "NOTDEFINED": "Undefined segment.",
            "RIGIDSEGMENT": "A rigid segment is continuous linear segment of pipe that cannot be deformed.",
            "SPOOL": "A type of rigid segment that is typically shorter and used for providing connectivity within a piping network.",
            "USERDEFINED": "User-defined segment."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcpipesegmenttype.htm"
    },
    "IfcPixelTexture": {
        "attributes": {
            "ColourComponents": "Indication whether the pixel values contain a 1, 2, 3, or 4 colour component.",
            "Height": "The number of pixels in height (T) direction.",
            "Pixel": "Flat list of hexadecimal values, each describing one pixel by 1, 2, 3, or 4 components.",
            "Width": "The number of pixels in width (S) direction."
        },
        "description": "Definition from IAI: An IfcPixelTexture provides a 2D image-based texture map as an explicit array of pixel values (image field). In contrary to the IfcImageTexture the IfcPixelTexture holds a 2 dimensional list of pixel color (and opacity) directly, instead of referencing to an URL.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcpixeltexture.htm"
    },
    "IfcPlacement": {
        "attributes": {
            "Dim": "The space dimensionality of this class, derived from the dimensionality of the location. Location.Dim",
            "Location": "The geometric position of a reference point, such as the center of a circle, of the item to be located."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A placement entity defines the local environment for the definition of a geometry item. It locates the item to be defined and, in the case of the axis placement subtypes, gives its orientation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcplacement.htm"
    },
    "IfcPlanarBox": {
        "attributes": {
            "Placement": "The _IfcAxis2Placement_ positions a local coordinate system for the definition of the rectangle. The origin of this local coordinate system serves as the lower left corner of the rectangular box.    > NOTE  In case of a 3D placement by IfcAxisPlacement3D the IfcPlanarBox is defined within the xy plane of the definition coordinate system."
        },
        "description": "Definition from ISO/CD 10303-46:1992: A planar box specifies an arbitrary rectangular box and its location in a two dimensional Cartesian coordinate system.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcplanarbox.htm"
    },
    "IfcPlanarExtent": {
        "attributes": {
            "SizeInX": "The extent in the direction of the x-axis.",
            "SizeInY": "The extent in the direction of the y-axis."
        },
        "description": "The planar extent defines the extent along the two axes of the two-dimensional coordinate system, independently of its position.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcplanarextent.htm"
    },
    "IfcPlane": {
        "description": "Definition from ISO/CD 10303-42:1992: A plane is an unbounded surface with a constant normal. A plane is defined by a point on the plane and the normal direction to the plane. The data is to be interpreted as follows:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcplane.htm"
    },
    "IfcPlate": {
        "description": "An IfcPlate is a planar and often flat part with constant thickness. A plate can be a structural part carrying loads between or beyond points of support, however it is not required to be load bearing. The location of the plate (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to IfcWall and IfcSlab (as floor slab)). ",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcplate.htm"
    },
    "IfcPlateType": {
        "description": "The element type IfcPlateType defines a list of commonly shared property set definitions of a thin planar element and an optional set of product representations (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "CURTAIN_PANEL": "A planar element within a curtain wall, often consisting of a frame with fixed glazing.",
            "NOTDEFINED": "Undefined linear element.",
            "SHEET": "A planar, flat and thin element, comes usually as metal sheet, and is often used as an additonal part within an assembly.",
            "USERDEFINED": "User-defined linear element."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcplatetype.htm"
    },
    "IfcPoint": {
        "description": "Definition from ISO/CD 10303-42:1992: An point is a location in some real Cartesian coordinate space R^m^, for m = 1, 2 or 3.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcpoint.htm"
    },
    "IfcPointOnCurve": {
        "attributes": {
            "BasisCurve": "The curve to which point parameter relates.",
            "Dim": "The space dimensionality of this class, determined by the space dimensionality of the basis curve. BasisCurve.Dim",
            "PointParameter": "The parameter value of the point location."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A point on curve is a point which lies on a curve. The point is determined by evaluating the curve at a specific parameter value. The coordinate space dimensionality of the point is that of the basis curve.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcpointoncurve.htm"
    },
    "IfcPointOnSurface": {
        "attributes": {
            "BasisSurface": "The surface to which the parameter values relate.",
            "Dim": "The space dimensionality of this class, determined by the space dimensionality of the basis surface. BasisSurface.Dim",
            "PointParameterU": "The first parameter value of the point location.",
            "PointParameterV": "The second parameter value of the point location."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A point on surface is a point which lies on a parametric surface. The point is determined by evaluating the surface at a particular pair of parameter values.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcpointonsurface.htm"
    },
    "IfcPolyLoop": {
        "attributes": {
            "Polygon": "List of points defining the loop. There are no repeated points in the list."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A poly loop is a loop with straight edges bounding a planar region in space. A poly loop is a loop of genus 1 where the loop is represented by an ordered coplanar collection of points forming the vertices of the loop. The loop is composed of straight line segments joining a point in the collection to the succeeding point in the collection. The closing segment is from the last to the first point in the collection. ",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcpolyloop.htm"
    },
    "IfcPolygonalBoundedHalfSpace": {
        "attributes": {
            "PolygonalBoundary": "Two-dimensional ~~polyline~~ bounded curve, defined in the xy plane of the position coordinate system.",
            "Position": "Definition of the position coordinate system for the bounding polyline ~~and the base surface~~."
        },
        "description": "The polygonal bounded half space is a special subtype of a half space solid, where the material of the half space used in Boolean expressions is bounded by a polygonal boundary. The base surface of the half space is positioned by its normal relativeto the object coordinate system (as defined at the supertype IfcHalfSpaceSolid), and its polygonal (with or without arc segments) boundary is defined in the XY plane of the position coordinate system established by the Position attribute, the subtraction body is extruded perpendicular to the XY plane of the position coordinate system, i.e. into the direction of the positive Z axis defined by the Position attribute.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcpolygonalboundedhalfspace.htm"
    },
    "IfcPolyline": {
        "attributes": {
            "Points": "The points defining the polyline."
        },
        "description": "Definition from ISO/CD 10303-42:1992: An IfcPolyline is a bounded curve of n -1 linear segments, defined by a list of n points, P1, P2 ... Pn. The curve is parameterized as follows:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcpolyline.htm"
    },
    "IfcPort": {
        "attributes": {
            "ConnectedFrom": "Reference to a port that is connected by the objectified relationship.",
            "ConnectedTo": "Reference to the port connection relationship. The relationship then refers to the other port to which this port is connected.",
            "ContainedIn": "Reference to the element to port connection relationship. The relationship then refers to the element in which this port is contained."
        },
        "description": "An IfcPort provides the means for an element to connect to other elements.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcport.htm"
    },
    "IfcPostalAddress": {
        "attributes": {
            "AddressLines": "The postal address. > NOTE: A postal address may occupy several lines (or elements) when recorded.  It is expected that normal usage will incorporate relevant elements of the following address concepts:  A location within a building (e.g. 3rd Floor) Building name (e.g. Interoperability House) Street number  (e.g. 6400) Street name (e.g. Alliance Boulevard). Typical content of address lines may vary in different  countries.",
            "Country": "The name of a country.",
            "InternalLocation": "An organization defined address for internal mail delivery.",
            "PostalBox": "An address that is implied by an identifiable mail drop.",
            "PostalCode": "The code that is used by the country's postal service.",
            "Region": "The name of a region. > NOTE: The counties of the United Kingdom and the states of North America are examples of regions.",
            "Town": "The name of a town."
        },
        "description": "The address for delivery of paper based mail.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifcpostaladdress.htm"
    },
    "IfcPreDefinedColour": {
        "description": "The pre defined colour determines those qualified names which can be used to identify a colour that is in scope of the current data exchange specification (in contrary to colour specification which defines the colour directly by its colour components).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcpredefinedcolour.htm"
    },
    "IfcPreDefinedCurveFont": {
        "description": "Definition from ISO/CD 10303-46:1992: The predefined curve font type is an abstract supertype provided to define an application specific curve font. The name label shall be constrained in the application protocol to values that are given specific meaning for curve fonts in that application protocol.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcpredefinedcurvefont.htm"
    },
    "IfcPreDefinedDimensionSymbol": {
        "description": "The pre defined dimension symbol is a pre defined symbol for the purpose to identify a dimension symbol by name. Allowable names are:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcpredefineddimensionsymbol.htm"
    },
    "IfcPreDefinedItem": {
        "attributes": {
            "Name": "The string by which the pre defined item is identified. Allowable values for the string are declared at the level of subtypes."
        },
        "description": "A pre defined item is a qualified name given to a style, font, etc., which is determined within the data exchange specification by convention on using the Name attribute value (in contrary to externally defined items, which are agreed by an external source).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcpredefineditem.htm"
    },
    "IfcPreDefinedPointMarkerSymbol": {
        "description": "The pre defined point marker symbol is a pre defined symbol for the purpose to identify a point marker by name. Allowable names are:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcpredefinedpointmarkersymbol.htm"
    },
    "IfcPreDefinedSymbol": {
        "description": "A predefined symbol is a symbol that gets its shape information by a conforming name that is specified within subtypes of the entity.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcpredefinedsymbol.htm"
    },
    "IfcPreDefinedTerminatorSymbol": {
        "description": "The pre defined terminator symbol is a pre defined symbol for the purpose to identify a terminator by name. Allowable names are:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcpredefinedterminatorsymbol.htm"
    },
    "IfcPreDefinedTextFont": {
        "description": "The pre defined text font determines those qualified names which can be used for fonts that are in scope of the current data exchange specification (in contrary to externally defined text fonts). There are two choices:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifcpredefinedtextfont.htm"
    },
    "IfcPresentationLayerAssignment": {
        "attributes": {
            "AssignedItems": "The set of layered items, which are assigned to this layer.",
            "Description": "Additional description of the layer.",
            "Identifier": "An (internal) identifier assigned to the layer.",
            "Name": "Name of the layer."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The presentation layer assignment entity assigns an identifying name and optionally a description to a set of presentation and representation items.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifcpresentationlayerassignment.htm"
    },
    "IfcPresentationLayerWithStyle": {
        "attributes": {
            "LayerBlocked": "A logical setting, TRUE indicates that the layer is set to 'Blocked', FALSE that the layer is set to 'Not blocked', UNKNOWN that such information is not available.",
            "LayerFrozen": "A logical setting, TRUE indicates that the layer is set to 'Frozen', FALSE that the layer is set to 'Not frozen', UNKNOWN that such information is not available.",
            "LayerOn": "A logical setting, TRUE indicates that the layer is set to 'On', FALSE that the layer is set to 'Off', UNKNOWN that such information is not available.",
            "LayerStyles": "Assignment of presentation styles to the layer to provide a default style for representation items. >  NOTE  In most cases the assignment of styles to a layer is restricted to an IfcCurveStyle representing the layer curve colour, layer curve thickness, and layer curve type."
        },
        "description": "An IfcPresentationLayerAssignmentWithStyle extends the presentation layer assignment with capabilities to define visibility control, access control and common style information.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationorganizationresource/lexical/ifcpresentationlayerwithstyle.htm"
    },
    "IfcPresentationStyle": {
        "attributes": {
            "Name": "Name of the presentation style."
        },
        "description": "Definition from IAI: An abstract generalization of style table for presentation information assigned to geometric representation items. It includes styles for curves, areas, surfaces, text and symbols. Style information may include colour, hatching, rendering, text fonts, etc.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcpresentationstyle.htm"
    },
    "IfcPresentationStyleAssignment": {
        "attributes": {
            "Styles": "A set of presentation styles that are assigned to styled items."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The presentation style assignment is a set of styles which are assigned to styled items for the purpose of presenting these styled items.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcpresentationstyleassignment.htm"
    },
    "IfcProcedure": {
        "attributes": {
            "ProcedureID": "An identifying designation given to a procedure.",
            "ProcedureType": "Predefined procedure types from which that required may be set.",
            "UserDefinedProcedureType": "A user defined procedure type."
        },
        "description": "An IfcProcedure is an identifiable step to be taken within a process that is considered to occur over zero or a non-measurable period of time.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcprocedure.htm"
    },
    "IfcProcess": {
        "attributes": {
            "IsPredecessorTo": "Relative placement in time, refers to the subsequent processes for which this process is predecessor.",
            "IsSuccessorFrom": "Relative placement in time, refers to the previous processes for which this process is successor.",
            "OperatesOn": "Set of Relationships to objects that are operated on by the process."
        },
        "description": "An action taking place in building construction with the intent of designing, costing, acquiring, constructing, or maintaining products or other and similar tasks or procedures. Processes are placed in sequence (including overlapping for parallel tasks) in time, the relationship IfcRelSequence it used to capture the predecessors and successors of the process. Processes can have resources assigned to it, this is handled by the relationship IfcRelAssignsToProcess.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcprocess.htm"
    },
    "IfcProduct": {
        "attributes": {
            "ObjectPlacement": "Placement of the product in space, the placement can either be absolute (relative to the world coordinate system), relative (relative to the object placement of another product), or constraint (e.g. relative to grid axes). It is determined by the various subtypes of IfcObjectPlacement, which includes the axis placement information to determine the  transformation for the object coordinate system.",
            "ReferencedBy": "Reference to the IfcRelAssignsToProduct relationship, by which other subtypes of IfcObject can be related to the product.",
            "Representation": "Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement."
        },
        "description": "Any object, or any aid to define, organize and annotate an object, that relates to a geometric or spatial context. Subtypes of IfcProduct usually hold a shape representation and a local placement within the project structure.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcproduct.htm"
    },
    "IfcProductDefinitionShape": {
        "attributes": {
            "HasShapeAspects": "Reference to the shape aspect that represents part of the shape or its feature distinctively.",
            "ShapeOfProduct": "The _IfcProductDefinitionShape_ shall be used to provide a representation for a single instance of _IfcProduct_."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A product definition shape identifies a product\u2019s shape as the conceptual idea of the form of a product.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcproductdefinitionshape.htm"
    },
    "IfcProductRepresentation": {
        "attributes": {
            "Description": "The word or group of words that characterize the product representation. It can be used to add additional meaning to the name of the product representation.",
            "Name": "The word or group of words by which the product representation is known.",
            "Representations": "Contained list of representations (including shape representations). Each member defines a valid representation of a particular type within a particular representation context."
        },
        "description": "The IfcProductRepresentation defines a representation of a product, including its (geometric or topological) representation. A product can have zero, one or many geometric representations, and a single geometric representation can be shared among various products using mapped representations.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcproductrepresentation.htm"
    },
    "IfcProductsOfCombustionProperties": {
        "attributes": {
            "CO2Content": "Carbon Dioxide (CO~2~) content of the products of combustion. This is measured in weight of CO~2~ per unit weight and is therefore unitless.",
            "COContent": "Carbon monoxide (CO) content of the products of combustion.This is measured in weight of CO per unit weight and is therefore unitless.",
            "N20Content": "Nitrous Oxide (N~2~O) content of the products of combustion. This is measured in weight of N~2~O per unit weight and is therefore unitless.",
            "SpecificHeatCapacity": "Specific heat of the products of combustion: heat energy absorbed per temperature unit. Usually measured in [J/kg K]."
        },
        "description": "Common definition to capture the properties of products of combustion generated by elements typically used within the context of building services and flow distribution systems.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcproductsofcombustionproperties.htm"
    },
    "IfcProfileDef": {
        "attributes": {
            "ProfileName": "Name of the profile type according to some standard profile table.",
            "ProfileType": "Defines the type of geometry into which this profile definition shall be resolved, either a curve or a surface area. In case of curve the profile should be referenced by a swept surface, in case of area the profile should be referenced by a swept area solid."
        },
        "description": "Definition from IAI: The IfcProfileDef is the supertype of all definitions of standard and arbitrary profiles within IFC. It is used to define a standard set of commonly used profiles by their parameters or by their explicit curve geometry. Those profile definitions are used within the geometry and geometric model resource to create either swept surfaces, swept area solids, or sectioned spines.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcprofiledef.htm"
    },
    "IfcProfileProperties": {
        "attributes": {
            "ProfileDefinition": "Optional reference to an instance of IfcProfileDef, which contains a further geometrical definition.",
            "ProfileName": "Standardized profile name as published in a profile table. All profile properties are applicable to this standardized profile name."
        },
        "description": "This is a collection of properties applicable to all linear structural members having a profile definition.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcprofileproperties.htm"
    },
    "IfcProject": {
        "attributes": {
            "LongName": "Long name for the project as used for reference purposes.",
            "Phase": "Current project phase, open to interpretation for all project partner, therefore given as IfcString.",
            "RepresentationContexts": "Context of the representations used within the project. When the project includes shape representations for its components, one or several geometric representation contexts need to be included that define e.g. the world coordinate system, the coordinate space dimensions, and/or the precision factor.",
            "UnitsInContext": "Units globally assigned to measure types used within the context of this project."
        },
        "description": "The undertaking of some design, engineering, construction, or maintenance activities leading towards a product. The project establishes the context for information to be exchanged or shared, and it may represent a construction project but does not have to.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcproject.htm"
    },
    "IfcProjectOrder": {
        "attributes": {
            "ID": "A unique identification assigned to a project order that enables its differentiation from other project orders.",
            "Status": "The current status of a project order.Examples of status values that might be used for a project order status include: - PLANNED - REQUESTED - APPROVED - ISSUED - STARTED - DELAYED - DONE"
        },
        "description": "An IfcProjectOrder sets common properties for project orders issued in a construction or facilities management project.",
        "predefined_types": {
            "CHANGEORDER": "An instruction to make a change to a product or work being undertaken and a description of the work that is to be performed.",
            "MAINTENANCEWORKORDER": "An instruction to carry out maintenance work and a description of the work that is to be performed.",
            "MOVEORDER": "An instruction to move persons and artefacts and a description of the move locations, objects to be moved, etc.",
            "NOTDEFINED": "Undefined type.",
            "PURCHASEORDER": "An instruction to purchase goods and/or services and a description of the goods and/or services to be purchased that is to be performed.",
            "USERDEFINED": "User-defined type.",
            "WORKORDER": "A general instruction to carry out work and a description of the work to be done. Note the difference between a work order generally and a maintenance work order."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifcprojectorder.htm"
    },
    "IfcProjectOrderRecord": {
        "attributes": {
            "Records": "Records in the sequence of occurrence the incident of a project order and the objects that are related to that project order. For instance, a maintenance incident will connect a work order with the objects (elements or assets) that are subject to the provisions of the work order"
        },
        "description": "An IfcProjectOrderRecord records information in sequence about the incidence of each order that is connected with one or a set of objects.",
        "predefined_types": {
            "CHANGE": "",
            "MAINTENANCE": "",
            "MOVE": "",
            "NOTDEFINED": "",
            "PURCHASE": "",
            "USERDEFINED": "",
            "WORK": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifcprojectorderrecord.htm"
    },
    "IfcProjectionCurve": {
        "description": "A projection curve is an annotated curve within a dimension that points to a point of the product shape that is measured.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcprojectioncurve.htm"
    },
    "IfcProjectionElement": {
        "description": "The IfcProjectionElement is a specialization of the general feature element to represent projections applied to building elements. It represents a solid attached to any element that has physical manifestation. Projections must be handled by all sectors and disciplines in AEC/FM industry, therefore the interoperability for opening elements is provided at this high level.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcprojectionelement.htm"
    },
    "IfcProperty": {
        "attributes": {
            "Description": "Informative text to explain the property.",
            "Name": "Name for this property. This label is the significant name string that defines the semantic meaning for the property.",
            "PartOfComplex": "Reference to the IfcComplexProperty in which the IfcProperty is contained.",
            "PropertyDependsOn": "The relating property on which the value of the property depends.",
            "PropertyForDependance": "The property on whose value that of another property depends."
        },
        "description": "An abstract generalization for all types of properties that can be associated with IFC objects through the property set mechanism.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcproperty.htm"
    },
    "IfcPropertyBoundedValue": {
        "attributes": {
            "LowerBoundValue": "Lower bound value for the interval defining the property value. If the value is not given, it indicates an open bound (all values to be lower than or equal to UpperBoundValue).",
            "Unit": "Unit for the upper and lower bound values, if not given, the default value for the measure type (given by the TYPE of the upper and lower bound values) is used as defined by the global unit assignment at IfcProject.",
            "UpperBoundValue": "Upper bound value for the interval defining the property value. If the value is not given, it indicates an open bound (all values to be greater than or equal to LowerBoundValue)."
        },
        "description": "A property with a bounded value (IfcPropertyBoundedValue) defines a property object which has a maximum of two (numeric or descriptive) values assigned, the first value specifying the upper bound and the second value specifying the lower bound. It defines a property - value bound (min-max) combination for which the property name, the upper bound value with measure type, the lower bound value with measure type (and optional the unit) is given.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertyboundedvalue.htm"
    },
    "IfcPropertyConstraintRelationship": {
        "attributes": {
            "Description": "A description that may apply additional information about a property constraint relationship.",
            "Name": "A name used to identify or qualify the property constraint relationship.",
            "RelatedProperties": "The properties to which a constraint is to be related.",
            "RelatingConstraint": "The constraint that is to be related."
        },
        "description": "An IfcPropertyConstraintRelationship is a relationship class that enables a constraint to be related to one or more properties.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstraintresource/lexical/ifcpropertyconstraintrelationship.htm"
    },
    "IfcPropertyDefinition": {
        "attributes": {
            "HasAssociations": "Reference to the relationship IfcRelAssociates and thus to those externally defined concepts, like classifications, documents, or library information, which are associated to the property definition."
        },
        "description": "The IfcPropertyDefinition defines the generalization of all characteristics (i.e. a grouping of individual properties), that may be assigned to objects. Currently, subtypes of IfcPropertyDefinition include property set definitions, and property sets..",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcpropertydefinition.htm"
    },
    "IfcPropertyDependencyRelationship": {
        "attributes": {
            "DependantProperty": "The dependant property.",
            "DependingProperty": "The property on which the relationship depends.",
            "Description": "Additional description of the dependency.",
            "Expression": "Expression that further describes the nature of the dependency relation.",
            "Name": "Name of the relationship that provides additional meaning to the nature of the dependency."
        },
        "description": "An IfcPropertyDependencyRelationship describes an identified dependency between the value of one property and that of another.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertydependencyrelationship.htm"
    },
    "IfcPropertyEnumeratedValue": {
        "attributes": {
            "EnumerationReference": "Enumeration from which a enumeration value has been selected. The referenced enumeration also establishes the unit of the enumeration value.",
            "EnumerationValues": "Enumeration values, which shall be listed in the referenced IfcPropertyEnumeration, if such a reference is provided."
        },
        "description": "A property with an enumerated value (IfcPropertyEnumeratedValue) defines a property object which has a value assigned which is chosen from an enumeration. It defines a property - value combination for which the property name, the value with measure type (and optional the unit) are given.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertyenumeratedvalue.htm"
    },
    "IfcPropertyEnumeration": {
        "attributes": {
            "EnumerationValues": "List of values that form the enumeration.",
            "Name": "Name of this enumeration.",
            "Unit": "Unit for the enumerator values, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject."
        },
        "description": "A collection of simple or measure values that define a prescribed set of alternatives from which 'enumeration values' are selected. This enables inclusion of enumeration values in property sets. IfcPropertyEnumeration provides a name for the enumeration as well as a list of unique (numeric or descriptive) values (that may have a measure type assigned). The entity defines the list of potential enumerators to be exchanged together (or separately) with properties of type IfcPropertyEnumeratedValue that selects their actual property values from this enumeration.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertyenumeration.htm"
    },
    "IfcPropertyListValue": {
        "attributes": {
            "ListValues": "List of values.",
            "Unit": "Unit for the list values, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject."
        },
        "description": "An IfcPropertyListValue defines a property that has several (numeric or descriptive) values assigned, these values are given by an ordered list.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertylistvalue.htm"
    },
    "IfcPropertyReferenceValue": {
        "attributes": {
            "PropertyReference": "Reference to another entity through one of the select types in IfcObjectReferenceSelect.",
            "UsageName": "Description of the use of the referenced value within the property."
        },
        "description": "The IfcPropertyReferenceValue allows a property value to be given by referencing other entities within the resource definitions of IFC. Those other entities are regarded as predefined complex properties and can be aggregated within a property set (IfcPropertySet). The allowable entities to be used as value references are given by the IfcObjectReferenceSelect.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertyreferencevalue.htm"
    },
    "IfcPropertySet": {
        "attributes": {
            "HasProperties": "Contained set of properties. For property sets defined as part of the IFC Object model, the property objects within a property set are defined as part of the standard. If a property is not contained within the set of predefined properties, its value has not been set at this time."
        },
        "description": "The IfcPropertySet defines all dynamically extensible properties. The property set is a container class that holds properties within a property tree. These properties are interpreted according to their name attribute.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcpropertyset.htm"
    },
    "IfcPropertySetDefinition": {
        "attributes": {
            "DefinesType": "The property style to which the property set might belong.",
            "PropertyDefinitionOf": "Reference to the relation to one or many objects that are characterized by the property definition. The reference may be omitted, if the property definition is used to define a style library and no instances, to which the particular style of property set is associated, exist yet."
        },
        "description": "An IfcPropertySetDefinition is a generalization of property sets, that are either:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcpropertysetdefinition.htm"
    },
    "IfcPropertySingleValue": {
        "attributes": {
            "NominalValue": "Value and measure type of this property.  >  NOTE  By virtue of the defined data type, that is selected from the SELECT IfcValue, the appropriate unit can be found within the IfcUnitAssignment, defined for the project if no value for the unit attribute is given.",
            "Unit": "Unit for the nominal value, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject."
        },
        "description": "A property with a single value (IfcPropertySingleValue) defines a property object which has a single (numeric or descriptive) value assigned. It defines a property - single value combination for which the property name, the value with measure type (and optionally the unit) is given.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertysinglevalue.htm"
    },
    "IfcPropertyTableValue": {
        "attributes": {
            "DefinedUnit": "Unit for the defined values, if not given, the default value for the measure type (given by the TYPE of the defined values) is used as defined by the global unit assignment at IfcProject.",
            "DefinedValues": "Defined values which are applicable for the scope as defined by the defining values.",
            "DefiningUnit": "Unit for the defining values, if not given, the default value for the measure type (given by the TYPE of the defining values) is used as defined by the global unit assignment at IfcProject.",
            "DefiningValues": "List of defining values, which determine the defined values.",
            "Expression": "Expression for the derivation of defined values from the defining values, the expression is given for information only, i.e. no automatic processing can be expected from the expression."
        },
        "description": "A property with a range value (IfcPropertyTableValue) defines a property object which has two lists of (numeric or descriptive) values assigned, the values specifying a table with two columns. The defining values provide the first column and establish the scope for the defined values (the second column). Interpolations are out of scope of the IfcPropertyTableValue. An optional Expression attribute may give the equation used for deriving the range value, which is for information purposes only.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcpropertytablevalue.htm"
    },
    "IfcProtectiveDeviceType": {
        "description": "An IfcProtectiveDeviceType is a device that breaks an electrical circuit when a stated electric current that passes through it is exceeded.",
        "predefined_types": {
            "CIRCUITBREAKER": "A mechanical switching device capable of making, carrying, and breaking currents under normal circuit conditions and also making, carrying for a specified time and breaking, current under specified abnormal circuit conditions such as those of short circuit.",
            "EARTHFAILUREDEVICE": "",
            "FUSEDISCONNECTOR": "A device that will electrically open the circuit after a period of prolonged, abnormal current flow.",
            "NOTDEFINED": "Undefined type.",
            "RESIDUALCURRENTCIRCUITBREAKER": "A device that opens, closes, or isolates a circuit and has short circuit and overload protection.  It attempts to break the circuit when there is a difference in current between any two phases.  May also be referred to as 'Ground Fault Interupter (GFI)' or 'Ground Fault Circuit Interuptor (GFCI)'",
            "RESIDUALCURRENTSWITCH": "A device that opens, closes or isolates a circuit and has no short circuit or overload protection.  May also be identified as a 'ground fault switch'.",
            "USERDEFINED": "User-defined type.",
            "VARISTOR": "A high voltage surge protection device."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcprotectivedevicetype.htm"
    },
    "IfcProxy": {
        "attributes": {
            "ProxyType": "High level (and only) semantic meaning attached to the IfcProxy, defining the basic construct type behind the Proxy, e.g. Product or Process.",
            "Tag": "The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level."
        },
        "description": "The IfcProxy is intended to be a kind of a container for wrapping objects which are defined by associated properties, which may or may not have a geometric representation and placement in space. A proxy may have a semantic meaning, defined by the Name attribute, and property definitions, attached through the property assignment relationship, which definition may be outside of the definitions given by the current release of IFC.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcproxy.htm"
    },
    "IfcPumpType": {
        "description": "The element type IfcPumpType defines a list of commonly shared property set definitions of a pump and an optional set of product representations. It is used to define a pump specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "CIRCULATOR": "A Circulator pump is a generic low-pressure, low-capacity pump. It may have a wet rotor and may be driven by a flexible-coupled motor.",
            "ENDSUCTION": "An End Suction pump, when mounted horizontally, has a single horizontal inlet on the impeller suction side and a vertical discharge. It may have a direct or close-coupled motor.",
            "NOTDEFINED": "Pump type has not been defined.",
            "SPLITCASE": "A Split Case pump, when mounted horizontally, has an inlet and outlet on each side of the impeller. The impeller can be easily accessed by removing the front of the impeller casing. It may have a direct or close-coupled motor.",
            "USERDEFINED": "User-defined pump type.",
            "VERTICALINLINE": "A Vertical Inline pump has the pump and motor close-coupled on the pump casing. The pump depends on the connected, horizontal piping for support, with the suction and discharge along the piping axis.",
            "VERTICALTURBINE": "A Vertical Turbine pump has a motor mounted vertically on the pump casing for either\n                wet-pit sump mounting or dry-well mounting."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcpumptype.htm"
    },
    "IfcQuantityArea": {
        "attributes": {
            "AreaValue": "Area measure value of this quantity."
        },
        "description": "A physical quantity, IfcQuantityArea, that defines a derived area measure to provide an element's physical property. It is normally derived from the physical properties of the element under the specific measure rules given by a method of measurement.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcquantityarea.htm"
    },
    "IfcQuantityCount": {
        "attributes": {
            "CountValue": "Count measure value of this quantity."
        },
        "description": "An physical quantity, IfcQuantityCount, that defines a derived count measure to provide an element's physical property. It is normally derived from the physical properties of the element under the specific measure rules given by a method of measurement.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcquantitycount.htm"
    },
    "IfcQuantityLength": {
        "attributes": {
            "LengthValue": "Length measure value of this quantity."
        },
        "description": "A physical quantity, IfcQuantityLength, that defines a derived length measure to provide an element's physical property. It is normally derived from the physical properties of the element under the specific measure rules given by a method of measurement.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcquantitylength.htm"
    },
    "IfcQuantityTime": {
        "attributes": {
            "TimeValue": "Time measure value of this quantity."
        },
        "description": "An element quantity that defines a time measure to provide an property of time related to an element. It is normally given by the recipe information of the element under the specific measure rules given by a method of measurement.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcquantitytime.htm"
    },
    "IfcQuantityVolume": {
        "attributes": {
            "VolumeValue": "Volume measure value of this quantity."
        },
        "description": "A physical quantity that defines a derived volume measure to provide an element's physical property. It is normally derived from the physical properties of the element under the specific measure rules given by a method of measurement.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcquantityvolume.htm"
    },
    "IfcQuantityWeight": {
        "attributes": {
            "WeightValue": "Mass measure value of this quantity."
        },
        "description": "A physical element quantity that defines a derived weight measure to provide an element's physical property. It is normally derived from the physical properties of the element under the specific measure rules given by a method of measurement.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcquantityresource/lexical/ifcquantityweight.htm"
    },
    "IfcRadiusDimension": {
        "description": "The radial dimension is a draughting callout that presents the radial length of a conic element. It consists of a dimension curve and may have projection curves (but is often defined without projection curves).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcradiusdimension.htm"
    },
    "IfcRailing": {
        "description": "Definition of IAI: The railing is a frame assembly adjacent to human circulation spaces and at some space boundaries where it is used in lieu of walls or to complement walls. Designed to aid humans, either as an optional physical support, or to prevent injury by falling. A list of references to accessory/mounting hardware for this railing might be given by including these assessories (IfcDiscreteAssessory) through the objectified relationship IfcRelAggregates.",
        "predefined_types": {
            "BALUSTRADE": "Similar to the definitions of a guardrail except the location is at the edge of a floor, rather then a stair or ramp. Examples are balustrates at roof-tops or balconies.",
            "GUARDRAIL": "A type of railing designed to guard human occupants from falling off a stair, ramp or landing where there is a vertical drop at the edge of such floors/landings.",
            "HANDRAIL": "A type of railing designed to serve as an optional structural support for loads applied by human occupants (at hand height). Generally located adjacent to ramps and stairs. Generally floor or wall mounted.",
            "NOTDEFINED": "Undefined railing element, no type information available.",
            "USERDEFINED": "User-defined railing element, a term to identify the user type is given by the attribute _IfcRailing.ObjectType._"
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrailing.htm"
    },
    "IfcRailingType": {
        "description": "The element type (IfcRailingType) defines a list of commonly shared property set definitions of a railing element and an optional set of product representations. It is used to define a railing specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "BALUSTRADE": "Similar to the definitions of a guardrail except the location is at the edge of a floor, rather then a stair or ramp. Examples are balustrates at roof-tops or balconies.",
            "GUARDRAIL": "A type of railing designed to guard human occupants from falling off a stair, ramp or landing where there is a vertical drop at the edge of such floors/landings.",
            "HANDRAIL": "A type of railing designed to serve as an optional structural support for loads applied by human occupants (at hand height). Generally located adjacent to ramps and stairs. Generally floor or wall mounted.",
            "NOTDEFINED": "Undefined railing element, no type information available.",
            "USERDEFINED": "User-defined railing element, a term to identify the user type is given by the attribute _IfcRailing.ObjectType._"
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrailingtype.htm"
    },
    "IfcRamp": {
        "attributes": {
            "ShapeType": "Predefined shape types for a ramp that are specified in an Enum."
        },
        "description": "Definition from ISO 6707-1:1989: Inclined way or floor joining two surfaces at different levels.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcramp.htm"
    },
    "IfcRampFlight": {
        "description": "Inclined slab segment, normally providing a human circulation link between two landings, floors or slabs at different elevations.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrampflight.htm"
    },
    "IfcRampFlightType": {
        "description": "The element type (IfcRampFlightType) defines a list of commonly shared property set definitions of a ramp flight and an optional set of product representations. It is used to define an ramp flight specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "NOTDEFINED": "Undefined ramp flight.",
            "SPIRAL": "A ramp flight with a circular or elliptic walking line.",
            "STRAIGHT": "A ramp flight with a straight walking line.",
            "USERDEFINED": "User-defined ramp flight."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrampflighttype.htm"
    },
    "IfcRationalBezierCurve": {
        "attributes": {
            "Weights": "The array of weights associated with the control points. This is derived from the weights data. IfcListToArray(WeightsData,0,SELF\\IfcBSplineCurve.UpperIndexOnControlPoints)",
            "WeightsData": "The supplied values of the weights."
        },
        "description": "A rational Bezier curve is a B-spline curve described in terms of control points and basic functions. It describes weights in addition to the control points defined at the supertype IfcBSplineCurve.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcrationalbeziercurve.htm"
    },
    "IfcRectangleHollowProfileDef": {
        "attributes": {
            "InnerFilletRadius": "Radius of the circular arcs, by which all four corners of the outer contour of rectangle are equally rounded. If not given, zero (= no rounding arcs) applies.",
            "OuterFilletRadius": "Radius of the circular arcs, by which all four corners of the outer contour of rectangle are equally rounded. If not given, zero (= no rounding arcs) applies.",
            "WallThickness": "Thickness of the material."
        },
        "description": "Definition from IAI: The IfcRectangleHollowProfileDef defines a section profile that provides the defining parameters of a rectangular (or square) hollow section to be used by the swept surface geometry or the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. A square hollow section can be defined by equal values for h and b. The centre of the position coordinate system is in the profiles centre of the bounding box (for symmetric profiles identical with the centre of gravity). Normally, the longer sides are parallel to the y-axis, the shorter sides parallel to the x-axis.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcrectanglehollowprofiledef.htm"
    },
    "IfcRectangleProfileDef": {
        "attributes": {
            "XDim": "The extent of the rectangle in the direction of the x-axis.",
            "YDim": "The extent of the rectangle in the direction of the y-axis."
        },
        "description": "Definition from IAI: The IfcRectangleProfileDef defines a rectangle as the profile definition used by the swept surface geometry or the swept area solid. It is given by its X extent and its Y extent, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcrectangleprofiledef.htm"
    },
    "IfcRectangularPyramid": {
        "attributes": {
            "Height": "The height of the apex above the plane of the base, measured in the direction of the placement Z axis, the _SELF\\IfcCsgPrimitive3D.Position.P[2]_.",
            "XLength": "The length of the base measured along the placement X axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[1]_.",
            "YLength": "The length of the base measured along the placement Y axis. It is provided by the inherited axis placement through _SELF\\IfcCsgPrimitive3D.Position.P[2]_."
        },
        "description": "Definition from ISO 10303-42:ed.2, 2000: A rectangular pyramid is a solid pyramid with a rectangular base. The apex of the pyramid is directly above the centre point of the base. The rectangular pyramid is specified by its position, which provides a placement coordinate system, its length, depth and height.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcrectangularpyramid.htm"
    },
    "IfcRectangularTrimmedSurface": {
        "attributes": {
            "BasisSurface": "Surface being trimmed.",
            "Dim": "BasisSurface.Dim",
            "U1": "First u parametric value.",
            "U2": "Second u parametric value.",
            "Usense": "Flag to indicate whether the direction of the first parameter of the trimmed surface agrees with or opposes the sense of u in the basis surface.",
            "V1": "First v parametric value.",
            "V2": "Second v parametric value.",
            "Vsense": "Flag to indicate whether the direction of the second parameter of the trimmed surface agrees with or opposes the sense of v in the basis surface."
        },
        "description": "Definition from ISO/CD 10303-42:1992: The trimmed surface is a simple bounded surface in which the boundaries are the constant parametric lines u~1~ = u1, u~2~ = u2, v~1~ = v1 and v~2~ = v2. All these values shall be within the parametric range of the referenced surface. Cyclic properties of the parameter range are assumed.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcrectangulartrimmedsurface.htm"
    },
    "IfcReferencesValueDocument": {
        "attributes": {
            "Description": "A description of the relationship to the document from which values may be referenced.",
            "Name": "A name used to identify or qualify the relationship to the document from which values may be referenced..",
            "ReferencedDocument": "A document such as a price list or quotation from which costs are obtained.",
            "ReferencingValues": "Costs obtained from a single document such as a price list or quotation."
        },
        "description": "An IfcReferencesValueDocument is a means of referencing many instances of IfcAppliedValue to a single document where the document is a price list, quotation, list of environmental impact values or other source of information.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccostresource/lexical/ifcreferencesvaluedocument.htm"
    },
    "IfcRegularTimeSeries": {
        "attributes": {
            "TimeStep": "A duration of time intervals between values.",
            "Values": "The collection of time series values."
        },
        "description": "In a regular time series, the data arrives predictably at predefined intervals. In a regular time series there is no need to store multiple time stamps and the algorithms for analyzing the time series are therefore significantly simpler. Using the start time provided in the supertype, the time step is used to identify the frequency of the occurrences of the list of values.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifcregulartimeseries.htm"
    },
    "IfcReinforcementBarProperties": {
        "attributes": {
            "BarCount": "The number of bars with identical nominal diameter and steel grade included in the specific reinforcement configuration.",
            "BarSurface": "Indicator for whether the bar surface is plain or textured.",
            "EffectiveDepth": "The effective depth, i.e. the distance of the specific reinforcement cross section area or reinforcement configuration in a row, counted from a common specific reference point. Usually the reference point is the upper surface (for beams and slabs) or a similar projection in a plane (for columns).",
            "NominalBarDiameter": "The nominal diameter defining the cross-section size of the reinforcing bar. The bar diameter should be identical for all bars included in the specific reinforcement configuration.",
            "SteelGrade": "The nominal steel grade defined according to local standards.",
            "TotalCrossSectionArea": "The total effective cross-section area of the reinforcement of a specific steel grade."
        },
        "description": "An IfcReinforcementProperties defines the set of properties for a specific combination of reinforcement bar steel grade, bar type and effective depth.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcreinforcementbarproperties.htm"
    },
    "IfcReinforcementDefinitionProperties": {
        "attributes": {
            "DefinitionType": "Descriptive type name applied to reinforcement definition properties.",
            "ReinforcementSectionDefinitions": "The list of section reinforcement properties attached to the reinforcement definition properties."
        },
        "description": "An IfcReinforcementDefinitionProperties defines the cross section properties of reinforcement included in reinforced concrete building elements. The property set definition may be used both in conjunction with insitu and precast structures.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcreinforcementdefinitionproperties.htm"
    },
    "IfcReinforcingBar": {
        "attributes": {
            "BarLength": "The total length of the reinforcing bar. The total length of bended bars are calculated according to local standards with corrections for the bends.",
            "BarRole": "The role, purpose or usage of the bar, i.e. the kind of loads and stresses it is intended to carry.",
            "BarSurface": "Indicator for whether the bar surface is plain or textured.",
            "CrossSectionArea": "The effective cross-section area of the reinforcing bar.",
            "NominalDiameter": "The nominal diameter defining the cross-section size of the reinforcing bar."
        },
        "description": "A steel bar, usually with manufactured deformations in the surface, used in concrete and masonry construction to provide additional strength.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcreinforcingbar.htm"
    },
    "IfcReinforcingElement": {
        "attributes": {
            "SteelGrade": "The nominal steel grade defined according to local standards."
        },
        "description": "Bars, wires, strands, and other slender members embedded in concrete in such a manner that the reinforcement and the concrete act together in resisting forces.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcreinforcingelement.htm"
    },
    "IfcReinforcingMesh": {
        "attributes": {
            "LongitudinalBarCrossSectionArea": "The effective cross-section area of the longitudinal bars of the mesh.",
            "LongitudinalBarNominalDiameter": "The nominal diameter denoting the cross-section size of the longitudinal bars.",
            "LongitudinalBarSpacing": "The spacing between the longitudinal bars. Note: an even distribution of bars is presumed; other cases are handled by Psets.",
            "MeshLength": "The overall length of the mesh measured in its longitudinal direction.",
            "MeshWidth": "The overall width of the mesh measured in its transversal direction.",
            "TransverseBarCrossSectionArea": "The effective cross-section area of the transverse bars of the mesh.",
            "TransverseBarNominalDiameter": "The nominal diameter denoting the cross-section size of the transverse bars.",
            "TransverseBarSpacing": "The spacing between the transverse bars. Note: an even distribution of bars is presumed; other cases are handled by Psets."
        },
        "description": "A series of longitudinal and transverse wires or bars of various gauges, arranged at right angles to each other and welded at all points of intersection; usually used for concrete slab reinforcement. Also known as welded wire fabric.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifcreinforcingmesh.htm"
    },
    "IfcRelAggregates": {
        "description": "The aggregation relationship IfcRelAggregates is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The aggregation relationship can be applied to all subtypes of object.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelaggregates.htm"
    },
    "IfcRelAssigns": {
        "attributes": {
            "RelatedObjects": "Related objects, which are assigned to a single object. The type of the single (or relating) object is defined in the subtypes of IfcRelAssigns.",
            "RelatedObjectsType": "Particular type of the assignment relationship. It can constrain the applicable object types, used within the role of RelatedObjects."
        },
        "description": "The assignment relationship, IfcRelAssigns, is a generalization of \"link\" relationships among instances of IfcObject and its various 1^st^ level subtypes. A link denotes the specific association through which one object (the client) applies the services of other objects (the suppliers), or through which one object may navigate to other objects.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassigns.htm"
    },
    "IfcRelAssignsTasks": {
        "attributes": {
            "TimeForTask": "Contained object for the time related information for the work schedule element."
        },
        "description": "An IfcRelAssignsTasks is a relationship class that assigns an IfcTask to an IfcWorkControl. The assignment is further qualified by attaching an IfcScheduleTimeControl to the assignment to give the time constraints of the work task, when assigned to a work plan or schedule.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcrelassignstasks.htm"
    },
    "IfcRelAssignsToActor": {
        "attributes": {
            "ActingRole": "Role of the actor played within the context of the assignment to the object(s).",
            "RelatingActor": "Reference to the information about the actor. It comprises the information about the person or organization and its addresses."
        },
        "description": "This objectified relationship (IfcRelAssignsToActor) handles the assignment of objects (subtypes of IfcObject) to an actor (subtypes of IfcActor).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassignstoactor.htm"
    },
    "IfcRelAssignsToControl": {
        "attributes": {
            "RelatingControl": "Reference to the control that applies an control about objects."
        },
        "description": "This objectified relationship (IfcRelAssignsToControl) handles the assignment of a control (subtype of IfcControl) to other objects (subtypes of IfcObject, with the exception of controls).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassignstocontrol.htm"
    },
    "IfcRelAssignsToGroup": {
        "attributes": {
            "RelatingGroup": "Reference to group that finally contains all assigned group members."
        },
        "description": "This objectified relationship (IfcRelAssignsToGroup) handles the assignment of objects (subtypes of IfcObject) to a group (subtypes of IfcGroup).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassignstogroup.htm"
    },
    "IfcRelAssignsToProcess": {
        "attributes": {
            "QuantityInProcess": "Quantity of the object specific for the operation by this process.",
            "RelatingProcess": "Reference to the process to which the objects are assigned to."
        },
        "description": "This objectified relationship (IfcRelAssignsToProcess) handles the assignment of an object as an item the process operates on. Process is related to the product that it operate on (normally as input or output) through this relationship. Processes can operate on things other than products, and can operate in ways other than input and output.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassignstoprocess.htm"
    },
    "IfcRelAssignsToProduct": {
        "attributes": {
            "RelatingProduct": "Reference to the Product to which the objects are assigned to."
        },
        "description": "This objectified relationship IfcRelAssignsToProduct handles the assignment of objects (subtypes of IfcObject) to a product (subtypes of IfcProduct).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassignstoproduct.htm"
    },
    "IfcRelAssignsToProjectOrder": {
        "description": "An IfcRelAssignsToProjectOrder is a relationship class that captures the incidence of a project order for a set of objects and whose occurrences can be recorded within a project record in sequence as a series of events.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifcrelassignstoprojectorder.htm"
    },
    "IfcRelAssignsToResource": {
        "attributes": {
            "RelatingResource": "Reference to the resource to which the objects are assigned to."
        },
        "description": "This objectified relationship (IfcRelAssignsToResource) handles the assignment of objects (subtypes of IfcObject) to a resource (subtypes of IfcResource).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassignstoresource.htm"
    },
    "IfcRelAssociates": {
        "attributes": {
            "RelatedObjects": "Objects or Types, to which the external references or information is associated."
        },
        "description": "The association relationship (IfcRelAssociates) refer to external sources of information (most notably a classification, library or document). There is no dependency implied by the association.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassociates.htm"
    },
    "IfcRelAssociatesAppliedValue": {
        "attributes": {
            "RelatingAppliedValue": ""
        },
        "description": "An IfcRelAssociatesAppliedValue is a subtype of IfcRelAssociates that enables the association of an instance of IfcAppliedValue with one or more instances of IfcObject.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifcrelassociatesappliedvalue.htm"
    },
    "IfcRelAssociatesApproval": {
        "attributes": {
            "RelatingApproval": "Reference to approval that is being applied using this relationship."
        },
        "description": "The entity IfcRelAssociatesApproval is used to apply approval information defined by IfcApproval, in IfcApprovalResource schema, to all subtypes of IfcRoot.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccontrolextension/lexical/ifcrelassociatesapproval.htm"
    },
    "IfcRelAssociatesClassification": {
        "attributes": {
            "RelatingClassification": "Classification applied to the objects."
        },
        "description": "This objectified relationship (IfcRelAssociatesClassification) handles the assignment of a classification object (items of the select IfcClassificationSelect) to objects (subtypes of IfcObject).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassociatesclassification.htm"
    },
    "IfcRelAssociatesConstraint": {
        "attributes": {
            "Intent": "The intent of the constraint usage with regard to its related IfcConstraint and IfcObjects, IfcPropertyDefinitions or IfcRelationships. Typical values can be e.g. RATIONALE or EXPECTED PERFORMANCE.",
            "RelatingConstraint": "Reference to constraint that is being applied using this relationship."
        },
        "description": "The entity IfcRelAssociatesConstraint is used to apply constraint information defined by IfcConstraint, in IfcConstraintResource schema, to all subtypes of IfcRoot.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccontrolextension/lexical/ifcrelassociatesconstraint.htm"
    },
    "IfcRelAssociatesDocument": {
        "attributes": {
            "RelatingDocument": "Document information or reference which is applied to the objects."
        },
        "description": "This objectified relationship (IfcRelAssociatesDocument) handles the assignment of a document information (items of the select IfcDocumentSelect) to objects (subtypes of IfcObject).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassociatesdocument.htm"
    },
    "IfcRelAssociatesLibrary": {
        "attributes": {
            "RelatingLibrary": "Reference to a library, from which the definition of the property set is taken."
        },
        "description": "This objectified relationship (IfcRelAssociatesLibrary) handles the assignment of a library item (items of the select IfcLibrarySelect) to objects (subtypes of IfcObject).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelassociateslibrary.htm"
    },
    "IfcRelAssociatesMaterial": {
        "attributes": {
            "RelatingMaterial": "Material definition (either a single material, a list of materials, or a set of material layers) assigned to the elements."
        },
        "description": "Objectified relationship between a material definition and elements or element types to which this material definition applies. The material definition can be:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelassociatesmaterial.htm"
    },
    "IfcRelAssociatesProfileProperties": {
        "attributes": {
            "ProfileOrientation": "The provision of an plane angle or a direction as the measure to orient the profile definition within the elements coordinate system. * For _IfcStructuralCurveMember_ the _IfcPlaneAngleMeasure_ defines the \u03b2 angle, for columns the derivation from the structural x axis and for beams the derivation from the structural z axis. The _IfcDirection_ precisely defines the orientation of the profile's structural z axis within the structural coordinate system of the analysis model.",
            "ProfileSectionLocation": "Reference to a shape aspect with a single member of the ShapeRepresentations list. This member holds the location at which the profile properties apply.",
            "RelatingProfileProperties": "Profile property definition assigned to the instances."
        },
        "description": "Definition from IAI: The IfcRelAssociatesProfileProperties is an objectified relationship between non geometric profile properties (subtypes of IfcProfileProperties) and elements to which these properties apply, e.g. building elements and building element types as used within the structural engineering domain for steel, timber or concrete structures.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcrelassociatesprofileproperties.htm"
    },
    "IfcRelConnects": {
        "description": "A connectivity relationship (IfcRelConnects) that connects objects under some criteria. As a general connectivity it does not imply constraints, however subtypes of the relationship define the applicable object types for the connectivity relationship and the semantics of the particular connectivity.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelconnects.htm"
    },
    "IfcRelConnectsElements": {
        "attributes": {
            "ConnectionGeometry": "Relationship to the control class, that provides the geometrical constraints of the connection.",
            "RelatedElement": "Reference to an Element that is connected by the objectified relationship.",
            "RelatingElement": "Reference to an Element that is connected by the objectified relationship."
        },
        "description": "The IfcRelConnectsElements objectified relationship provides the generalization of the connectivity between elements. It is a 1 to 1 relationship. The concept of two elements being physically or logically connected is described independently from the connecting elements. The connectivity may be related to the shape representation of the connected entities by providing a connection geometry.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelconnectselements.htm"
    },
    "IfcRelConnectsPathElements": {
        "attributes": {
            "RelatedConnectionType": "Indication of the connection type in relation to the path of the RelatingObject.",
            "RelatedPriorities": "Priorities for connection. It refers to the layers of the RelatedObject.",
            "RelatingConnectionType": "Indication of the connection type in relation to the path of the RelatingObject.",
            "RelatingPriorities": "Priorities for connection. It refers to the layers of the RelatingObject."
        },
        "description": "The IfcRelConnectsPathElements relationship provides the connectivity information between two elements, which have a path information. Currently it is applied to IfcWall and IfcWallStandardCase.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcrelconnectspathelements.htm"
    },
    "IfcRelConnectsPortToElement": {
        "attributes": {
            "RelatedElement": "Reference to an Element that is connected by the objectified relationship.",
            "RelatingPort": "Reference to an Port that is connected by the objectified relationship."
        },
        "description": "An IfcRelConnectsPortToElement defines the relationship that is made between a port and the IfcElement in which it is contained. It is a 1 to 1 relationship.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelconnectsporttoelement.htm"
    },
    "IfcRelConnectsPorts": {
        "attributes": {
            "RealizingElement": "Defines the element that realizes a port connection relationship.",
            "RelatedPort": "Reference to the second port that is connected by the objectified relationship.",
            "RelatingPort": "Reference to the first port that is connected by the objectified relationship."
        },
        "description": "An IfcRelConnectsPorts defines the relationship that is made between two ports at their point of connection. It may include the connection geometry between two ports.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelconnectsports.htm"
    },
    "IfcRelConnectsStructuralActivity": {
        "attributes": {
            "RelatedStructuralActivity": "Reference to an instance of IfcStructuralActivity (or its subclasses) which is acting upon the specified structural element (represented by a respective structural representation entity).",
            "RelatingElement": "Reference to an instance of IfcStructuralItem or IfcBuildingElement (or its subclasses) to which the specified action is applied."
        },
        "description": "The IfcRelConnectsStructuralActivity relationship connects a structural activity (either an action or reaction) to a structural member or a building element.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcrelconnectsstructuralactivity.htm"
    },
    "IfcRelConnectsStructuralElement": {
        "attributes": {
            "RelatedStructuralMember": "The structural member that is associated with the element of which it represents the analytical idealization.",
            "RelatingElement": "The physical element, representing a design or detailing part, that is connected to the structural member as its (partial) analytical  idealization."
        },
        "description": "The one-to-one relationship assigns a structural member (as instance of IfcStructuralMember or its subclasses) to a physical element  (as instance of IfcElement or its subclasses) to keep the association between the design or detailing element and the structural analysis element. ",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcrelconnectsstructuralelement.htm"
    },
    "IfcRelConnectsStructuralMember": {
        "attributes": {
            "AdditionalConditions": "Reference to instances describing additional connection properties.",
            "AppliedCondition": "Reference to an instance of _IfcBoundaryCondition_ which is used to define the connections properties.    >  NOTE  The boundary condition applied to a member-connection-relationship is also called \"release\"",
            "ConditionCoordinateSystem": "Defines a new coordinate system used for the description of the connection properties. The usage of this coordinate system is described more detailed in the definition of the subtypes of this entity definition.",
            "RelatedStructuralConnection": "Reference to an instance of IfcStructuralConnection (or its subclasses) which is connected to the specified structural member.",
            "RelatingStructuralMember": "Reference to an instance of IfcStructuralMember (or its subclasses) which is connected to the specified structural connection.",
            "SupportedLength": "Defines the 'supported length' of this structural connection. See Fig. for more detail."
        },
        "description": "The entity IfcRelConnectsStructuralMember defines all needed properties describing the connection between structural members and structural connections (nodes or supports).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcrelconnectsstructuralmember.htm"
    },
    "IfcRelConnectsWithEccentricity": {
        "attributes": {
            "ConnectionConstraint": "The connection constraint explicitly states the eccentricity between a structural element and a structural connection, either given by two point (used to calculate the eccentricity), or by explicit x, y, and z offsets."
        },
        "description": "The entity IfcRelConnectsWithEccentricity adds the definition of eccentricity to the connection between a structural member and a structural connection (representing either a node or support). ",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcrelconnectswitheccentricity.htm"
    },
    "IfcRelConnectsWithRealizingElements": {
        "attributes": {
            "ConnectionType": "The type of the connection given for informal purposes, it may include labels, like 'joint', 'rigid joint', 'flexible joint', etc.",
            "RealizingElements": "Defines the elements that realize a connection relationship."
        },
        "description": "IfcRelConnectsWithRealizingElements defines a generic relationship that is made between two elements that require the realization of that relationship by means of further realizing elements.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelconnectswithrealizingelements.htm"
    },
    "IfcRelContainedInSpatialStructure": {
        "attributes": {
            "RelatedElements": "Set of ~~elements~~ products, which are contained within this level of the spatial structure hierarchy.",
            "RelatingStructure": "Spatial structure element, within which the element is contained. Any element can only be contained within one element of the project spatial structure."
        },
        "description": "This objectified relationship, IfcRelContainedInSpatialStructure, is used to assign elements to a certain level of the spatial project structure. Any element can only be assigned once to a certain level of the spatial structure. The question, which level is relevant for which type of element, can only be answered within the context of a particular project and might vary within the various regions.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelcontainedinspatialstructure.htm"
    },
    "IfcRelCoversBldgElements": {
        "attributes": {
            "RelatedCoverings": "Relationship to the set of coverings at this element.",
            "RelatingBuildingElement": "Relationship to the element that is covered."
        },
        "description": "The IfcRelCoversBldgElements is an objectified relationship between an element and one to many coverings, which cover the building element.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelcoversbldgelements.htm"
    },
    "IfcRelCoversSpaces": {
        "attributes": {
            "RelatedCoverings": "Relationship to the set of coverings covering this space.",
            "RelatedSpace": "Relationship to the space object that is covered."
        },
        "description": "The objectified relationship, IfcRelCoversSpace, relates a space object to one or many coverings, which faces (or is assigned to) the space.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelcoversspaces.htm"
    },
    "IfcRelDecomposes": {
        "attributes": {
            "RelatedObjects": "The objects being nested or aggregated.",
            "RelatingObject": "The object that represents the nest or aggregation."
        },
        "description": "The decomposition relationship, IfcRelDecomposes, defines the general concept of elements being composed or decomposed. The decomposition relationship denotes a whole/part hierarchy with the ability to navigate from the whole (the composition) to the parts and vice versa.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcreldecomposes.htm"
    },
    "IfcRelDefines": {
        "attributes": {
            "RelatedObjects": "Reference to the objects (or single object) to which the property definition applies."
        },
        "description": "A definition relationship (IfcRelDefines) that uses a type definition or property set definition (seens as partial type information) to define the properties of the object instance. It is a specific - occurrence relationship with implied dependencies (as the occurrence properties depend on the specific properties).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcreldefines.htm"
    },
    "IfcRelDefinesByProperties": {
        "attributes": {
            "RelatingPropertyDefinition": "Reference to the property set definition for that object or set of objects."
        },
        "description": "This objectified relationship (IfcRelDefinesByProperties) defines the relationships between property set definitions and objects. Properties are aggregated in property sets, property sets can be grouped to define an object type.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcreldefinesbyproperties.htm"
    },
    "IfcRelDefinesByType": {
        "attributes": {
            "RelatingType": "Reference to the type (or style) information for that object or set of objects."
        },
        "description": "This objectified relationship (IfcRelDefinesByType) defines the relationships between an object type and objects.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcreldefinesbytype.htm"
    },
    "IfcRelFillsElement": {
        "attributes": {
            "RelatedBuildingElement": "Reference to ~~building~~ element that occupies fully or partially the associated opening.",
            "RelatingOpeningElement": "Opening Element being filled by virtue of this relationship."
        },
        "description": "Objectified relationship between an opening element and an ~~building~~ element that fills (or partially fills) the opening element. It is an one-to-one relationship.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelfillselement.htm"
    },
    "IfcRelFlowControlElements": {
        "attributes": {
            "RelatedControlElements": "References control elements which may be used to impart control on the Distribution Element.",
            "RelatingFlowElement": "Relationship to a distribution flow element"
        },
        "description": "Objectified relationship between a distribution flow element occurrence instance and one-to-many control element occurrence instances. Currently it is applied to IfcDistributionFlowelEment and IfcDistributionControlElement.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcrelflowcontrolelements.htm"
    },
    "IfcRelInteractionRequirements": {
        "attributes": {
            "DailyInteraction": "Number of interactions occurring on a daily basis.",
            "ImportanceRating": "Represents the level of importance of interaction. 0 represents lowest importance, 1 represents highest importance.",
            "LocationOfInteraction": "The location where this interaction happens.",
            "RelatedSpaceProgram": "Related space program for the interaction requirement.",
            "RelatingSpaceProgram": "Relating space program for the interaction requirement."
        },
        "description": "The interaction requirement (IfcRelInteractionRequirements) is provided as a relationship that defines the requirements for the interaction (adjacency) of two spaces in the architectural program.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcarchitecturedomain/lexical/ifcrelinteractionrequirements.htm"
    },
    "IfcRelNests": {
        "description": "The nesting relationship IfcRelNests is a special type of the general composition/decomposition (or whole/part) relationship IfcRelDecomposes. The nesting relationship can be applied to all subtypes of object, however it requires both the whole and the part to be of the same object type.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelnests.htm"
    },
    "IfcRelOccupiesSpaces": {
        "description": "IfcRelOccupiesSpaces is a relationship class that further constrains the parent relationship IfcRelAssignsToActor to a relationship between occupants (IfcOccupant) and either a space (IfcSpace), a collection of spaces (IfcZone), a building storey (IfcBuildingStorey), or a building (IfcBuilding).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcreloccupiesspaces.htm"
    },
    "IfcRelOverridesProperties": {
        "attributes": {
            "OverridingProperties": "A property set, which contains those properties, that have a different value for the subset of objects."
        },
        "description": "The objectified relationship (IfcRelOverridesProperties) defines the relationships between objects and a standard property set. It also defines a set of properties, which values override the standard values given within the standard property set.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcreloverridesproperties.htm"
    },
    "IfcRelProjectsElement": {
        "attributes": {
            "RelatedFeatureElement": "Reference to the _IfcFeatureElementAddition_ that defines an addition to the volume of the element, by using a Boolean addition operation. An example is a projection at the associated element.",
            "RelatingElement": "Element at which a projection is created by the associated _IfcProjectionElement_."
        },
        "description": "The IfcRelProjectsElement is an objectified relationship between an element and one projection element that creates a modifier to the shape of the element. This relationship implies a Boolean operation of addition for the geometric bodies of the building element and the projection element.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelprojectselement.htm"
    },
    "IfcRelReferencedInSpatialStructure": {
        "attributes": {
            "RelatedElements": "Set of products, which are referenced within this level of the spatial structure hierarchy. > NOTE  Referenced elements are contained elsewhere within the spatial structure, they are referenced additionally by this spatial structure element, e.g., because they span several stories.",
            "RelatingStructure": "Spatial structure element, within which the element is referenced. Any element can be contained within zero, one or many elements of the project spatial structure."
        },
        "description": "This objectified relationship, IfcRelReferencedInSpatialStructure, is used to assign elements in addition to those levels of the project spatial structure, in which they are referenced, but not primarily contained.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelreferencedinspatialstructure.htm"
    },
    "IfcRelSchedulesCostItems": {
        "description": "An IfcRelSchedulesCostItems is a subtype of IfcRelAssignsToControl that enables one or many instances of IfcCostItem to be assigned to an instance of IfcCostSchedule.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedmgmtelements/lexical/ifcrelschedulescostitems.htm"
    },
    "IfcRelSequence": {
        "attributes": {
            "RelatedProcess": "Reference to the Process, that is the successor.",
            "RelatingProcess": "Reference to the Process, that is the predecessor.",
            "SequenceType": "The way in which the time lag applies to the sequence.",
            "TimeLag": "Time Duration of the sequence, it is the time lag between the predecessor and the successor as specified by the SequenceType."
        },
        "description": "This objectified relationship handles the concatenation of processes over time. The sequence is defined as relationship between two processes. The related object is the successor of the relating object, being the predecessor. A time lag is assigned to a sequence, and the sequence type defines the way in which the time lag applies to the sequence.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelsequence.htm"
    },
    "IfcRelServicesBuildings": {
        "attributes": {
            "RelatedBuildings": "Spatial structure elements (including site, building, storeys) that are serviced by the system.",
            "RelatingSystem": "System that services the Buildings."
        },
        "description": "An objectified relationship that defines the relationship between a system and the sites, buildings, storeys or spaces, it serves. Examples of systems are:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelservicesbuildings.htm"
    },
    "IfcRelSpaceBoundary": {
        "attributes": {
            "ConnectionGeometry": "Physical representation of the space boundary. Provided as a **curve or** surface given within the LCS of the space.",
            "InternalOrExternalBoundary": "Defines, whether the Space Boundary is internal (Internal), or external, i.e. adjacent to open space (that can be an partially enclosed space, such as terrace (External).",
            "PhysicalOrVirtualBoundary": "Defines, whether the Space Boundary is physical (Physical) or virtual (Virtual).",
            "RelatedBuildingElement": "Reference to ~~Building~~ Element, that defines the Space Boundaries.",
            "RelatingSpace": "Reference to one spaces that is delimited by this boundary."
        },
        "description": "The space boundary (IfcRelSpaceBoundary) defines the physical or virtual delimiter of a space as its relationship to the surrounding elements.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelspaceboundary.htm"
    },
    "IfcRelVoidsElement": {
        "attributes": {
            "RelatedOpeningElement": "Reference to the ~~opening~~ feature subtraction element which defines a void in the associated ~~opening~~ element.",
            "RelatingBuildingElement": "Reference to ~~building~~ element in which a void is created by associated ~~opening~~ feature subtraction element."
        },
        "description": "Objectified relationship between an ~~building~~ element and one opening element that creates a void in the element. It is a one-to-one relationship. This relationship implies a Boolean operation of subtraction between the geometric bodies of the element and the opening.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcrelvoidselement.htm"
    },
    "IfcRelationship": {
        "description": "The abstract generalization of all objectified relationships in IFC. Objectified relationships are the preferred way to handle relationships among objects. This allows to keep relationship specific properties directly at the relationship and opens the possibility to later handle relationship specific behavior.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcrelationship.htm"
    },
    "IfcRelaxation": {
        "attributes": {
            "InitialStress": "Stress at the beginning. Given as relative to the yield stress of the material and is therefore dimensionless.",
            "RelaxationValue": "Time dependent loss of stress, relative to initial stress and therefore dimensionless."
        },
        "description": "Measure of the decrease in stress over long time interval resulting from plastic flow. It describes the time dependent relative relaxation value for a given initial stress level at constant strain.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcrelaxation.htm"
    },
    "IfcRepresentation": {
        "attributes": {
            "ContextOfItems": "Definition of the representation context for which the different subtypes of representation are valid.",
            "Items": "Set of geometric representation items that are defined for this representation.",
            "LayerAssignments": "Assignment of the whole representation to a single or multiple layer(s). The _LayerAssigments_ can be overridden by _LayerAssigments_ of the _IfcRepresentationItem_'s within the list of _Items_. > NOTE  Implementation agreements can restrict the maximum number of layer assignments to 1.",
            "OfProductRepresentation": "Reference to the product shape, for which it is the shape representation.",
            "RepresentationIdentifier": "The optional identifier of the representation as used within a project.",
            "RepresentationMap": "Use of the representation within an _IfcRepresentationMap_. If used, this _IfcRepresentation_ may be assigned to many representations as one of its _Items_ using an _IfcMappedItem_. Using _IfcRepresentationMap_ is the way to share one representation (often of type _IfcShapeRepresentation_) by many products.",
            "RepresentationType": "The description of the type of a representation context. The representation type defines the type of geometry or topology used for representing the product representation. More information is given at the subtypes _IfcShapeRepresentation_ and _IfcTopologyRepresentation_.   The supported values for context type are to be specified by implementers agreements."
        },
        "description": "Definition from ISO/CD 10303-43:1992: A representation is one or more representation items that are related in a specified representation context as the representation of some concept.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcrepresentation.htm"
    },
    "IfcRepresentationContext": {
        "attributes": {
            "ContextIdentifier": "The optional identifier of the representation context as used within a project.",
            "ContextType": "The description of the type of a representation context. The supported values for context type are to be specified by implementers agreements.",
            "RepresentationsInContext": "All shape representations that are defined in the same representation context."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A representation context is a context in which a set of representation items are related.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcrepresentationcontext.htm"
    },
    "IfcRepresentationItem": {
        "attributes": {
            "LayerAssignments": "Assignment of the representation item to a single or multiple layer(s). The _LayerAssignments_ can override a _LayerAssignments_ of the _IfcRepresentation_ it is used  within the list of _Items_. > NOTE  Implementation agreements can restrict the maximum number of layer assignments to 1.",
            "StyledByItem": "Reference to the _IfcStyledItem_ that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve."
        },
        "description": "Definition from ISO/CD 10303-43:1992: A representation item is an element of product data that participates in one or more representations or contributes to the definition of another representation item. A representation item contributes to the definition of another representation item when it is referenced by that representation item.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcrepresentationitem.htm"
    },
    "IfcRepresentationMap": {
        "attributes": {
            "MapUsage": "",
            "MappedRepresentation": "A representation that is mapped to at least one mapped item.",
            "MappingOrigin": "An axis2 placement that defines the position about which the mapped representation is mapped."
        },
        "description": "Definition from ISO/CD 10303-43:1992: A representation map is the identification of a representation and a representation item in that representation for the purpose of mapping. The representation item defines the origin of the mapping. The representation map is used as the source of a mapping by a mapped item.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcrepresentationmap.htm"
    },
    "IfcResource": {
        "attributes": {
            "ResourceOf": "Reference to the IfcRelAssignsToResource relationship and thus pointing to those objects, which are used as resources."
        },
        "description": "The IfcResource contains the information needed to represent the costs, schedule, and other impacts from the use of a thing in a process. It is not intended to use IfcResource to model the general properties of the things themselves, while an optional linkage from IfcResource to the things to be used can be specified (i.e. the relationship from subtypes of IfcResource to IfcProduct through the IfcRelAssignsToResource relationship).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcresource.htm"
    },
    "IfcRevolvedAreaSolid": {
        "attributes": {
            "Angle": "Angle through which the sweep will be made. This angle is measured from the plane of the sweep.",
            "Axis": "Axis about which revolution will take place.",
            "AxisLine": "The line of the axis of revolution. IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcCurve() || IfcLine(Axis.Location,    IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector(Axis.Z,1.0))"
        },
        "description": "A revolved area solid (IfcRevolvedAreaSolid) is a solid created by revolving a planar bounded surface about an axis. Both, the axis and planar bounded surface shall be in the same plane and the axis shall not intersect the interior of the swept area. If the swept area has inner boundaries, i.e. holes defined, then those holes shall be swept into holes of the solid. The direction of revolution is clockwise when viewed along the axis in the positive direction.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcrevolvedareasolid.htm"
    },
    "IfcRibPlateProfileProperties": {
        "attributes": {
            "Direction": "Defines the direction of profile definition as described on figure above.",
            "RibHeight": "Height of the ribs.",
            "RibSpacing": "Spacing between the axes of the ribs.",
            "RibWidth": "Width of the ribs.",
            "Thickness": "Defines the thickness of the structural face member."
        },
        "description": "Instances of the entity IfcRibPlateProfileProperties shall be used for a parameterized definition of rib plates.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcribplateprofileproperties.htm"
    },
    "IfcRightCircularCone": {
        "attributes": {
            "BottomRadius": "",
            "Height": ""
        },
        "description": "Definition from ISO/CD 10303-42:1992: A right circular cone is a CSG primitive in the form of a cone. It is defined by an axis, a point on the axis, (...) and a distance giving the location along the axis from the point to the base of the cone. In addition, a radius is given (...).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcrightcircularcone.htm"
    },
    "IfcRightCircularCylinder": {
        "attributes": {
            "Height": "",
            "Radius": ""
        },
        "description": "Definition from ISO/CD 10303-42:1992: A right circular cylinder is a CSG primitive in the form of a solid cylinder of finite height. It is defined by an axis point at the centre of one planar circular face, an axis, a height, and a radius. The faces are perpendicular to the axis and are circular discs with the specified radius. The height is the distance from the first circular face centre in the positive direction of the axis to the second circular face centre.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcrightcircularcylinder.htm"
    },
    "IfcRoof": {
        "attributes": {
            "ShapeType": "Predefined shape types for a roof that are specified in an enumeration."
        },
        "description": "Definition from ISO 6707-1:1989: Construction enclosing the building from above.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcroof.htm"
    },
    "IfcRoot": {
        "attributes": {
            "Description": "Optional description, provided for exchanging informative comments.",
            "GlobalId": "Assignment of a globally unique identifier within the entire software world.",
            "Name": "Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.",
            "OwnerHistory": "Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE: only the last modification in stored."
        },
        "description": "Definition from IAI: The IfcRoot is the most abstract and root class for all IFC entity definitions that roots in the kernel or in subsequent layers of the IFC object model. It is therefore the common supertype all all IFC entities, beside those defined in an IFC resource schema. All entities that are subtypes of IfcRoot can be used independently, whereas resource schema entities, that are not subtypes of IfcRoot, are not supposed to be independent entities.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifcroot.htm"
    },
    "IfcRoundedEdgeFeature": {
        "attributes": {
            "Radius": "The radius of the feature cross section."
        },
        "description": "An edge feature with a rounded cross section shape.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedcomponentelements/lexical/ifcroundededgefeature.htm"
    },
    "IfcRoundedRectangleProfileDef": {
        "attributes": {
            "RoundingRadius": "Radius of the circular arcs, by which all four corners of the rectangle are equally rounded. If not given, zero (= no rounding arcs) applies."
        },
        "description": "Definition from IAI: The IfcRoundedRectangleProfileDef defines a rectangle with equally rounded corners as the profile definition used by the swept surface geometry or the swept area solid. It is given by the X extent, the Y extent, and the radius for the rounded corners, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, i.e. in the center of the bounding box.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcroundedrectangleprofiledef.htm"
    },
    "IfcSIUnit": {
        "attributes": {
            "Dimensions": "The dimensional exponents of SI units are derived by function _IfcDimensionsForSiUnit_. IfcDimensionsForSiUnit (SELF.Name)",
            "Name": "The word, or group of words, by which the SI unit is referred to.",
            "Prefix": "The SI Prefix for defining decimal multiples and submultiples of the unit."
        },
        "description": "Definition from ISO/CD 10303-41:1992: An SI unit is the fixed quantity used as a standard in terms of which items are measured as defined by ISO 1000 (clause 2).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcsiunit.htm"
    },
    "IfcSanitaryTerminalType": {
        "description": "IfcSanitaryTerminalType defines a particular type of IfcFlowTerminal that is a fixed appliance or terminal usually supplied with water and used for drinking, cleaning or foul water disposal or that is an item of equipment directly used with such an appliance or terminal.",
        "predefined_types": {
            "BATH": "Sanitary appliance for immersion of the human body or parts of it.",
            "BIDET": "Waste water appliance for washing the excretory organs while sitting astride the bowl.",
            "CISTERN": "A water storage unit attached to a sanitary terminal that is fitted with a device, operated automatically or by the user, that discharges water to cleanse a water closet (toilet) pan, urinal or slop hopper.",
            "NOTDEFINED": "Undefined type.",
            "SANITARYFOUNTAIN": "A sanitary terminal that provides a low pressure jet of water for a specific purpose.",
            "SHOWER": "Installation or waste water appliance that emits a spray of water to wash the human body.",
            "SINK": "Waste water appliance for receiving, retaining or disposing of domestic, culinary, laboratory or industrial process liquids.",
            "TOILETPAN": "Soil appliance for the disposal of excrement.",
            "URINAL": "Soil appliance that receives urine and directs it to a waste outlet.",
            "USERDEFINED": "User-defined type.",
            "WASHHANDBASIN": "Waste water appliance for washing the upper parts of the body.",
            "WCSEAT": "Hinged seat that fits on the top of a water closet (WC) pan.\n{ .deprecated}\n> DEPRECATION&nbsp; Enumerator shall not be used in IFC4."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcplumbingfireprotectiondomain/lexical/ifcsanitaryterminaltype.htm"
    },
    "IfcScheduleTimeControl": {
        "attributes": {
            "ActualDuration": "The actual duration of the task.",
            "ActualFinish": "The date on which a task is actually finished.",
            "ActualStart": "The date on which a task is actually started.   NOTE: The scheduled start date must be greater than or equal to the earliest start date. No constraint is applied to the actual start date with respect to the scheduled start date since a task may be started earlier than had originally been scheduled if circumstances allow.",
            "Completion": "The extent of completion expressed as a ratio or percentage.",
            "EarlyFinish": "The earliest date on which a task can be finished.",
            "EarlyStart": "The earliest date on which a task can be started.",
            "FinishFloat": "The difference between the late finish and early finish of a task. Finish float measures how long an task's finish can be delayed and still not have an impact on the overall duration of a schedule.",
            "FreeFloat": "The amount of time during which the start or finish of a task may be varied without any effect on the overall programme of work.",
            "IsCritical": "A flag which identifies whether a scheduled task is a critical item within the programme.  NOTE: A task becomes critical when the float time becomes zero or negative.",
            "LateFinish": "The latest date on which a task can be finished.",
            "LateStart": "The latest date on which a task can be started.",
            "RemainingTime": "The amount of time remaining to complete a task.  NOTE: The time remaining in which to complete a task may be determined both for tasks which have not yet started and those which have. Remaining time for a task not yet started has the same value as the scheduled duration. For a task already started, remaining time is calculated as the difference between the scheduled finish and the point of analysis.",
            "ScheduleDuration": "The amount of time which is scheduled for completion of a task.  NOTE: Scheduled Duration may be calculated as the time from scheduled start date to scheduled finish date.",
            "ScheduleFinish": "The date on which a task is scheduled to be finished.  NOTE: The scheduled finish date must be greater than or equal to the earliest finish date.",
            "ScheduleStart": "The date on which a task is scheduled to be started. NOTE: The scheduled start date must be greater than or equal to the earliest start date.",
            "ScheduleTimeControlAssigned": "The assigned schedule time control in the relationship.",
            "StartFloat": "The difference between the late start and early start of a task. Start float measures how long an task's start can be delayed and still not have an impact on the overall duration of a schedule.",
            "StatusTime": "The date or time at which the status of the tasks within the schedule is analyzed.",
            "TotalFloat": "The difference between the duration available to carry out a task and the scheduled duration of the task.  NOTE: Total Float time may be calculated as being the difference between the scheduled duration of a task and the available duration from earliest start to latest finish. Float time may be either positive, zero or negative. Where it is zero or negative, the task becomes critical."
        },
        "description": "The IfcScheduleTimeControl captures the time-related information about a process including the different types (i.e. actual, or scheduled) of starting and ending times, duration, float times, etc.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcscheduletimecontrol.htm"
    },
    "IfcSectionProperties": {
        "attributes": {
            "EndProfile": "The cross section profile at the end point of the longitudinal section.",
            "SectionType": "An indicator whether a specific piece of a cross section is uniform or tapered in longitudinal direction.",
            "StartProfile": "The cross section profile at the start point of the longitudinal section."
        },
        "description": "An IfcSectionProperties defines the cross section properties for a single longitudinal piece of a cross section.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcsectionproperties.htm"
    },
    "IfcSectionReinforcementProperties": {
        "attributes": {
            "CrossSectionReinforcementDefinitions": "The set of reinforcment properties attached to a section reinforcement properties definition.",
            "LongitudinalEndPosition": "The end position in longitudinal direction for the section reinforcement properties.",
            "LongitudinalStartPosition": "The start position in longitudinal direction for the section reinforcement properties.",
            "ReinforcementRole": "The role, purpose or usage of the reinforcement, i.e. the kind of loads and stresses it is intended to carry, defined for the section reinforcement properties.",
            "SectionDefinition": "Definition of the cross section profile and longitudinal section type.",
            "TransversePosition": "The position for the section reinforcement properties in transverse direction."
        },
        "description": "An IfcSectionReinforcementProperties defines the cross section properties of reinforcement for a single longitudinal piece of a cross section with a specific reinforcement usage type.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcsectionreinforcementproperties.htm"
    },
    "IfcSectionedSpine": {
        "attributes": {
            "CrossSectionPositions": "Position coordinate systems for the cross sections that form the sectioned spine. The profiles defining the cross sections are positioned within the xy plane of the corresponding position coordinate system.",
            "CrossSections": "A list of at least two cross sections, each defined within the xy plane of the position coordinate system of the cross section. The position coordinate system is given by the corresponding list CrossSectionPositions.",
            "Dim": "The dimensionality of the spine curve is always 3. 3",
            "SpineCurve": "A single composite curve, that defines the spine curve. Each of the composite curve segments correspond to the part between two cross-sections."
        },
        "description": "Definition from ISO/DIS 10303-42-ed2:1999: A sectioned spine is a representation of the shape of a three dimensional object composed of a spine curve and a number of planar cross sections. The shape is defined between the first element of cross sections and the last element of this set.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcsectionedspine.htm"
    },
    "IfcSensorType": {
        "description": "An IfcSensorType defines a particular type of sensor which is used for detection in a control system such as a building automation control system.",
        "predefined_types": {
            "CO2SENSOR": "",
            "FIRESENSOR": "A device that senses or detects fire",
            "FLOWSENSOR": "A device that senses or detects flow in a fluid.",
            "GASSENSOR": "A device that senses or detects gas concentration (other than CO2)",
            "HEATSENSOR": "A device that senses or detects heat.",
            "HUMIDITYSENSOR": "A device that senses or detects humidity.",
            "LIGHTSENSOR": "A device that senses or detects light.",
            "MOISTURESENSOR": "A device that senses or detects moisture.",
            "MOVEMENTSENSOR": "A device that senses or detects movement.",
            "NOTDEFINED": "Undefined type.",
            "PRESSURESENSOR": "A device that senses or detects pressure.",
            "SMOKESENSOR": "A device that senses or detects smoke.",
            "SOUNDSENSOR": "A device that senses or detects sound.",
            "TEMPERATURESENSOR": "A device that senses or detects temperature.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcbuildingcontrolsdomain/lexical/ifcsensortype.htm"
    },
    "IfcServiceLife": {
        "attributes": {
            "ServiceLifeDuration": "The length or duration of a service life.",
            "ServiceLifeType": "Predefined service life types from which that required may be set."
        },
        "description": "An IfcServiceLife is the period of time that an artefact (typically a product or asset) will last.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcservicelife.htm"
    },
    "IfcServiceLifeFactor": {
        "attributes": {
            "LowerValue": "Lower of the three values assigned to the service life factor.",
            "MostUsedValue": "Most used of the three values assigned to the service life factor.",
            "UpperValue": "Upper of the three values assigned to the service life factor."
        },
        "description": "An IfcServiceLifeFactor captures the various factors that impact upon the expected service life of an artefact.",
        "predefined_types": {
            "A_QUALITYOFCOMPONENTS": "",
            "B_DESIGNLEVEL": "",
            "C_WORKEXECUTIONLEVEL": "",
            "D_INDOORENVIRONMENT": "",
            "E_OUTDOORENVIRONMENT": "",
            "F_INUSECONDITIONS": "",
            "G_MAINTENANCELEVEL": "",
            "NOTDEFINED": "",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcservicelifefactor.htm"
    },
    "IfcShapeAspect": {
        "attributes": {
            "Description": "The word or group of words that characterize the shape aspect. It can be used to add additional meaning to the name of the aspect.",
            "Name": "The word or group of words by which the shape aspect is known. It is a tag to indicate the particular semantic of a component within the product definition shape, used to provide meaning. Example: use the tag \"Glazing\" to define which component of a window shape defines the glazing area.",
            "PartOfProductDefinitionShape": "Reference to the product definition shape of which this class is an aspect.",
            "ProductDefinitional": "An indication that the shape aspect is on the physical boundary of the product definition shape. If the value of this attribute is TRUE, it shall be asserted that the shape aspect being identified is on such a boundary. If the value is FALSE, it shall be asserted that the shape aspect being identified is not on such a boundary. If the value is UNKNOWN, it shall be asserted that it is not known whether or not the shape aspect being identified is on such a boundary.  --- EXAMPLE: Would be FALSE for a center line, identified as shape aspect; would be TRUE for a cantilever. ---",
            "ShapeRepresentations": "List of ~~shape~~ representations. Each member defines a valid representation of a particular type within a particular representation context as being an aspect (or part) of a product definition."
        },
        "description": "Definition from ISO/CD 10303-41:1992: The shape aspect is an identifiable element of the shape of a product.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcshapeaspect.htm"
    },
    "IfcShapeModel": {
        "attributes": {
            "OfShapeAspect": "Reference to the shape aspect, for which it is the shape representation."
        },
        "description": "The IfcShapeModel represents the concept of a particular geometric and/or topological representation of a product's shape or a product component's shape within a representation context. This representation context has to be a geometric representation context (with the exception of topology representations without associated geometry). The two subtypes are IfcShapeRepresentation to cover the geometric models (or sets) that represent a shape, and IfcTopologyRepresentation to cover the conectivity of a product or product component. The topology may or may not have geometry associated.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcshapemodel.htm"
    },
    "IfcShapeRepresentation": {
        "description": "Definition from ISO/CD 10303-42:1992: The shape representation is a specific kind of representation that represents a shape.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcshaperepresentation.htm"
    },
    "IfcShellBasedSurfaceModel": {
        "attributes": {
            "Dim": "The space dimensionality of this class, it is always 3. 3",
            "SbsmBoundary": ""
        },
        "description": "Definition from ISO/CD 10303-42:1992: A shell based surface model is described by a set of open or closed shells of dimensionality 2. The shells shall not intersect except at edges and vertices. In particular, distinct faces may not intersect. A complete face of one shell may be shared with another shell. Coincident portions of shells shall both reference the same faces, edges and vertices defining the coincident region. There shall be at least one shell.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcshellbasedsurfacemodel.htm"
    },
    "IfcSimpleProperty": {
        "description": "A generalization of a single property object. The various subtypes of IfcSimpleProperty establish different ways in which a property value can be set.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpropertyresource/lexical/ifcsimpleproperty.htm"
    },
    "IfcSite": {
        "attributes": {
            "LandTitleNumber": "The land title number (designation of the site within a regional system).",
            "RefElevation": "Datum elevation relative to sea level.",
            "RefLatitude": "World Latitude at reference point (most likely defined in legal description). Defined as integer values for degrees, minutes, seconds, and, optionally, millionths of seconds with respect to the world geodetic system WGS84. > Latitudes are measured relative to the geodetic equator, north of the equator by positive values - from 0 till +90,   south of the equator by negative values - from 0 till  -90.",
            "RefLongitude": "World Longitude at reference point (most likely defined in legal description). Defined as integer values for degrees, minutes, seconds, and, optionally, millionths of seconds with respect to the world geodetic system WGS84. > Longitudes are measured relative to the geodetic zero meridian, nominally the same as the Greenwich prime meridian: longitudes west of the zero meridian have positive values - from 0 till +180, longitudes east of the zero meridian have negative values - from 0 till -180.",
            "SiteAddress": "Address given to the site for postal purposes."
        },
        "description": "Definition from ISO 6707-1:1989: Area where construction works are undertaken.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcsite.htm"
    },
    "IfcSlab": {
        "description": "A slab is a component of the construction that normally encloses a space vertically. The slab may provide the lower support (floor) or upper construction (roof slab) in any space in a building. It shall be noted, that only the core or constructional part of this construction is considered to be a slab. The upper finish (flooring, roofing) and the lower finish (ceiling, suspended ceiling) are considered to be coverings. A special type of slab is the landing, described as a floor section to which one or more stair flights or ramp flights connect. May or may not be adjacent to a building storey floor.",
        "predefined_types": {
            "BASESLAB": "The slab is used to represent a floor slab against the ground (and thereby being a part of the foundation). Another name is mat foundation.",
            "FLOOR": "The slab is used to represent a floor slab.",
            "LANDING": "The slab is used to represent a landing within a stair or ramp.",
            "NOTDEFINED": "",
            "ROOF": "The slab is used to represent a roof slab (either flat or sloped).",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcslab.htm"
    },
    "IfcSlabType": {
        "description": "The element type (IfcSlabType) defines a list of commonly shared property set definitions of a slab and an optional set of product representations. It is used to define a slab specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "BASESLAB": "The slab is used to represent a floor slab against the ground (and thereby being a part of the foundation). Another name is mat foundation.",
            "FLOOR": "The slab is used to represent a floor slab.",
            "LANDING": "The slab is used to represent a landing within a stair or ramp.",
            "NOTDEFINED": "",
            "ROOF": "The slab is used to represent a roof slab (either flat or sloped).",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcslabtype.htm"
    },
    "IfcSlippageConnectionCondition": {
        "attributes": {
            "SlippageX": "Slippage of that connection. Defines the maximum displacement in x-direction without any loading applied.",
            "SlippageY": "Slippage of that connection. Defines the maximum displacement in y-direction without any loading applied.",
            "SlippageZ": "Slippage of that connection. Defines the maximum displacement in z-direction without any loading applied."
        },
        "description": "Instances of the entity IfcSlippageConnectionCondition shall be used to describe connection properties needed to specify slippage.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcslippageconnectioncondition.htm"
    },
    "IfcSolidModel": {
        "attributes": {
            "Dim": "The space dimensionality of this class, it is always 3. 3"
        },
        "description": "Definition from ISO/CD 10303-42:1992: A solid model is a complete representation of the nominal shape of a product such that all points in the interior are connected. Any point can be classified as being inside, outside, or on the boundary of a solid. There are several different types of solid model representations.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcsolidmodel.htm"
    },
    "IfcSoundProperties": {
        "attributes": {
            "IsAttenuating": "If TRUE, values represent sound attenuation. If FALSE, values represent sound generation.",
            "SoundScale": "Reference sound scale",
            "SoundValues": "Sound values at a specific frequency. There may be cases where less than eight values are specified."
        },
        "description": "Common definition to capture the properties of sound typically used within the context of building services and flow distribution systems. Sound properties are sound power or pressure levels across eight octave bands specifying the amount of sound generation or sound attenuation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcsoundproperties.htm"
    },
    "IfcSoundValue": {
        "attributes": {
            "Frequency": "The frequency of the sound.",
            "SoundLevelSingleValue": "A sound pressure or sound power value. For sound pressure levels, the values are measured in decibels at a reference pressure of 20 microPascals for the referenced octave band frequency. For sound power levels, the values are measured in decibels at a reference power of 1 picowatt(10\\^(-12) watt) for the referenced octave band frequency.",
            "SoundLevelTimeSeries": "A time series of sound pressure or sound power values. For sound pressure levels, the values are measured in decibels at a reference pressure of 20 microPascals for the referenced octave band frequency. For sound power levels, the values are measured in decibels at a reference power of 1 picowatt(10\\^(-12) watt) for the referenced octave band frequency."
        },
        "description": "A sound value or time series of sound values at a specified frequency.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcsoundvalue.htm"
    },
    "IfcSpace": {
        "attributes": {
            "BoundedBy": "Reference to Set of Space Boundaries that defines the physical or virtual delimitation of that Space.",
            "ElevationWithFlooring": "Level of flooring of this space; the average shall be taken, if the space ground surface is sloping or if there are level differences within this space.",
            "HasCoverings": "Reference to _IfcCovering_ by virtue of the objectified relationship _IfcRelCoversSpaces_. It defines the concept of a space having coverings assigned. Those coverings may represent different flooring, or tiling areas. >  NOTE  Coverings are often managed by the space, and not by the building element, which they cover.",
            "InteriorOrExteriorSpace": "Defines, whether the Space is interior (Internal), or exterior (External), i.e. part of the outer space."
        },
        "description": "A space represents an area or volume bounded actually or theoretically. Spaces are areas or volumes that provide for certain functions within a building.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcspace.htm"
    },
    "IfcSpaceHeaterType": {
        "description": "The element type IfcSpaceHeaterType defines a list of commonly shared property set definitions of a space heater and an optional set of product representations. It is used to define a space heater specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "BASEBOARDHEATER": "",
            "CONVECTOR": "A heat-distributing unit that operates with gravity-circulated air.",
            "FINNEDTUBEUNIT": "",
            "NOTDEFINED": "Undefined space heater type.",
            "PANELRADIATOR": "",
            "SECTIONALRADIATOR": "",
            "TUBULARRADIATOR": "",
            "UNITHEATER": "",
            "USERDEFINED": "User-defined space heater type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcspaceheatertype.htm"
    },
    "IfcSpaceProgram": {
        "attributes": {
            "HasInteractionReqsFrom": "Set of inverse relationships to space or work interaction requirement objects (FOR RelatedObject).",
            "HasInteractionReqsTo": "Set of inverse relationships to space or work interaction requirements (FOR RelatingObject).",
            "MaxRequiredArea": "The maximum floor area programmed for this space (according to client requirements)",
            "MinRequiredArea": "The minimum floor area programmed for this space (according to client requirements)",
            "RequestedLocation": "Location within the building structure, requested for the space.",
            "SpaceProgramIdentifier": "Identifier for this space program. It often refers to a number (or code) assigned to the space program. Example: R-001.",
            "StandardRequiredArea": "The floor area programmed for this space (according to client requirements)."
        },
        "description": "Architectural program for a space in the building or facility being designed; essentially the requirements definition for such a building space.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcarchitecturedomain/lexical/ifcspaceprogram.htm"
    },
    "IfcSpaceThermalLoadProperties": {
        "attributes": {
            "ApplicableValueRatio": "Percentage of use requirement or criteria applicable to the space, interpretation depends on the source type.",
            "MaximumValue": "The maximum thermal load value. If this value is less than zero (negative), then the thermal load is lost from the space. If the value is greater than zero (positive), then the thermal load is a gain to the space. If the minimum value is not specified, then this value is the actual value. At least one of the maximum, minimum, or time series values must be specified.",
            "MinimumValue": "The minimum thermal load value. If this value is less than zero (negative), then the thermal load is lost from the space. If the value is greater than zero (positive), then the thermal load is a gain to the space. The requirement for the inclusion of this attribute is dependent on the load source. At least one of the maximum, minimum, or time series values must be specified.",
            "PropertySource": "The source of the space thermal load properties (e.g., are these design values, measured values, etc.).",
            "SourceDescription": "Further specification for the source, which might be specific for a region or project. E.g. whether the heat gain from Person is caused by specific activities.",
            "ThermalLoadSource": "Source of the thermal loss or gain. Depending on the source, the maximum and minimum values have to be interpreted. Refer to the space usage in Pset_SpaceProgramCommon to determine thermal loads associated with the activity levels of people.",
            "ThermalLoadTimeSeriesValues": "A time series of the thermal load values. If a value is less than zero (negative), then the thermal load is lost from the space. If the value is greater than zero (positive), then the thermal load is a gain to the space. These values are contributed from the specified thermal load source. At least one of the maximum, minimum, or time series values must be specified.",
            "ThermalLoadType": "Defines the type of thermal load (e.g., sensible, latent, radiant, etc.).",
            "UserDefinedPropertySource": "This attribute must be defined if the PropertySource is USERDEFINED.",
            "UserDefinedThermalLoadSource": "This attribute must be defined if the ThermalLoadSource is USERDEFINED."
        },
        "description": "The space thermal load IfcSpaceThermalLoadProperties defines all thermal losses and gains occurring within a space or zone. Those losses or gains can either be requirements (desired values) or criteria (actual values). The thermal load source attribute defines an enumeration of possible sources of the thermal load. The maximum, minimum, time series and applicable value ratio values are all interpreted according to the source. The maximum and minimum values should not be used if time series values are provided.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgserviceelements/lexical/ifcspacethermalloadproperties.htm"
    },
    "IfcSpaceType": {
        "description": "The IfcSpaceType defines a list of commonly shared property set definitions of a space and an optional set of product representations. It is used to define an space specification (i.e. the specific space information, that is common to all occurrences of that space type).",
        "predefined_types": {
            "NOTDEFINED": "",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcspacetype.htm"
    },
    "IfcSpatialStructureElement": {
        "attributes": {
            "CompositionType": "Denotes, whether the predefined spatial structure element represents itself, or an aggregate (complex) or a part (part). The interpretation is given separately for each subtype of spatial structure element.",
            "ContainsElements": "Set of spatial containment relationships, that holds those elements, which are contained within this element of the project spatial structure. >  NOTE  The spatial containment relationship, established by IfcRelContainedInSpatialStructure, is required to be an hierarchical relationship, i.e. each element can only be assigned to 0 or 1 spatial structure element.",
            "LongName": "Long name for a spatial structure element, used for informal purposes. Maybe used in conjunction with the inherited Name attribute.",
            "ReferencesElements": "Set of spatial reference relationships, that holds those elements, which are referenced, but not contained, within this element of the project spatial structure. >  NOTE  The spatial reference relationship, established by IfcRelReferencedInSpatialStructure, is not required to be an hierarchical relationship, i.e. each element can be assigned to 0, 1 or many spatial structure elements. EXAMPLE  A curtain wall maybe contained in the ground floor, but maybe referenced in all floors, it reaches.",
            "ServicedBySystems": "Set of relationships to Systems, that provides a certain service to the Building. The relationship is handled by the objectified relationship IfcRelServicesBuildings."
        },
        "description": "A spatial structure element (IfcSpatialStructureElement) is the generalization of all spatial elements that might be used to define a spatial structure. That spatial structure is often used to provide a project structure to organize a building project.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcspatialstructureelement.htm"
    },
    "IfcSpatialStructureElementType": {
        "description": "The element type (IfcSpatialStructureElementType) defines a list of commonly shared property set definitions of a spatial structure element and an optional set of product representations. It is used to define an element specification (i.e. the specific element information, that is common to all occurrences of that element type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcspatialstructureelementtype.htm"
    },
    "IfcSphere": {
        "attributes": {
            "Radius": ""
        },
        "description": "Definition from ISO/CD 10303-42:1992: A sphere is a CSG primitive with a spherical shape defined by a centre and a radius.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcsphere.htm"
    },
    "IfcStackTerminalType": {
        "description": "The IfcStackTerminalType defines a particular type of IfcFlowTerminal placed at the top of a ventilating stack (to prevent ingress by birds, rainwater etc.) or rainwater pipe (to act as a collector or hopper for discharge from guttering).",
        "predefined_types": {
            "BIRDCAGE": "Guard cage, typically wire mesh, at the top of the stack preventing access by birds.",
            "COWL": "A cowling placed at the top of a stack to eliminate downdraft.",
            "NOTDEFINED": "Undefined type.",
            "RAINWATERHOPPER": "A box placed at the top of a rainwater downpipe to catch rainwater from guttering.",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcplumbingfireprotectiondomain/lexical/ifcstackterminaltype.htm"
    },
    "IfcStair": {
        "attributes": {
            "ShapeType": "Predefined shape types for a stair that are specified in an Enum."
        },
        "description": "Definition from ISO 6707-1:1989: Construction comprising a succession of horizontal stages (steps or landings) that make it possible to pass on foot to other levels.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcstair.htm"
    },
    "IfcStairFlight": {
        "attributes": {
            "NumberOfRiser": "Number of the risers included in the stair flight.",
            "NumberOfTreads": "Number of treads included in the stair flight.",
            "RiserHeight": "Vertical distance from tread to tread. The riser height is supposed to be equal for all stairs in a stair flight.",
            "TreadLength": "Horizontal distance from the front to the back of the tread. The tread length is supposed to be equal for all steps of the stair flight."
        },
        "description": "Assembly of building components in a single \"run\" of stair steps (not interrupted by a landing). The stair steps and any stringers are included in this object. A winder is regarded as part of a stair flight.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcstairflight.htm"
    },
    "IfcStairFlightType": {
        "description": "The element type (IfcStairFlightType) defines a list of commonly shared property set definitions of a stair flight and an optional set of product representations. It is used to define an stair flight specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "CURVED": "A stair flight with a curved walking line.",
            "FREEFORM": "A stair flight with a free form walking line (and outer boundaries).",
            "NOTDEFINED": "Undefined stair flight.",
            "SPIRAL": "A stair flight with a circular or elliptic walking line.",
            "STRAIGHT": "A stair flight with a straight walking line.",
            "USERDEFINED": "User-defined stair flight.",
            "WINDER": "A stair flight with a walking line including straight and curved sections."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcstairflighttype.htm"
    },
    "IfcStructuralAction": {
        "attributes": {
            "CausedBy": "Optional reference to an instance of IfcStructuralReaction representing a result of another structural analysis model which creates this action upon the considered structural analysis model.",
            "DestabilizingLoad": "Indicates if this action may cause a stability problem. If it is 'FALSE', no further investigations regarding stability problems are necessary."
        },
        "description": "A structural action is a structural activity that acts upon a structural item or building element.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralaction.htm"
    },
    "IfcStructuralActivity": {
        "attributes": {
            "AppliedLoad": "Reference to the load resource, which is used to define the load type, direction and load values. The specified load types are provided in the IfcStructuralLoadResource presented at the end of this document.",
            "AssignedToStructuralItem": "References to the IfcRelConnectsStructuralActivity relationship by which activities can be associated to structural representations.",
            "GlobalOrLocal": "Indicates if the load values are defined by using the local  coordinate system or the global project coordinate system."
        },
        "description": "The abstract entity IfcStructuralActivity combines the definition of actions (such as forces, displacement, etc) and reactions (supports and deformations) which are specified by using the basic load definitions from the_IfcStructuralLoadResource_. It also uses the inherited capabilities for the definition of a location and a local coordinate system.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralactivity.htm"
    },
    "IfcStructuralAnalysisModel": {
        "attributes": {
            "HasResults": "References to all result groups available for this structural analysis model.",
            "LoadedBy": "References to all load groups to be analyzed.",
            "OrientationOf2DPlane": "If the selected model type (PredefinedType) describes a 2D system the orientation is needed to define the upright direction to the focused plane (z-axes). This is needed because all data for the structural analysis model (structural members, structural activities) are defined by using 3-D space. The orientation is given in relation to the coordinate system of the project. By 3D systems this value is not asserted."
        },
        "description": "The IfcStructuralAnalysisModel is used to assemble all information needed to represent a structural analysis model. It encompasses certain general properties (such as analysis type), references to all contained structural members, structural supports or connecting members, the connection properties, as well as loads and the respective load results.",
        "predefined_types": {
            "IN_PLANE_LOADING_2D": "",
            "LOADING_3D": "",
            "NOTDEFINED": "",
            "OUT_PLANE_LOADING_2D": "",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralanalysismodel.htm"
    },
    "IfcStructuralConnection": {
        "attributes": {
            "AppliedCondition": "Optional reference to an instance of IfcBoundaryCondition which defines the support condition of this 'connection'.",
            "ConnectsStructuralMembers": "References to the IfcRelConnectsStructuralMembers relationship by which structural members can be associated to structural connections."
        },
        "description": "The abstract entity IfcStructuralConnection is the superclass of entities representing structural supports or connecting elements (nodes). Point connections, curve connections and surface connections are supported.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralconnection.htm"
    },
    "IfcStructuralConnectionCondition": {
        "attributes": {
            "Name": "Optionally defines a name for this connection condition."
        },
        "description": "Instances of the entity IfcStructuralConnectionCondition or its respective subclasses shall be used to describe more rarely needed connection properties.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralconnectioncondition.htm"
    },
    "IfcStructuralCurveConnection": {
        "description": "Instances of the entity IfcStructuralCurveConnection shall be used to describe 'linear nodes' or 'linear supports', i.e. lines where two or more face members (walls, plates) are joined. All values defined by AppliedCondition are given within a coordinate system which is derived from the local coordinate system defined by this instance.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralcurveconnection.htm"
    },
    "IfcStructuralCurveMember": {
        "description": "Definition from IAI: Instances of the entity IfcStructuralCurveMember shall be used to describe linear structural elements. Profile and material properties are defined by using objectified relationships:",
        "predefined_types": {
            "CABLE": "",
            "COMPRESSION_MEMBER": "",
            "NOTDEFINED": "",
            "PIN_JOINED_MEMBER": "",
            "RIGID_JOINED_MEMBER": "",
            "TENSION_MEMBER": "",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralcurvemember.htm"
    },
    "IfcStructuralCurveMemberVarying": {
        "description": "Definition from IAI: Instances of the entity IfcStructuralCurveMemberVarying shall be used to describe linear structural elements with varying profile properties.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralcurvemembervarying.htm"
    },
    "IfcStructuralItem": {
        "attributes": {
            "AssignedStructuralActivity": "Inverse relationship to all structural activities (i.e. to actions or reactions) which are assigned to this structural member."
        },
        "description": "**Definition",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralitem.htm"
    },
    "IfcStructuralLinearAction": {
        "attributes": {
            "ProjectedOrTrue": "Defines if the load values are given by using the length of the member on which they act (true length) or by using the projected length resulting from the loaded member and the global project coordinate system. It is only considered if the global project coordinate system is used, and if the action is of type IfcStructuralLinearAction or IfcStructuralPlanarAction."
        },
        "description": "Instances of the entity IfcStructuralLinearAction are used to define constant linear actions. Structural loads applicable to linear actions are IfcStructuralLoadLinearForce and IfcStructuralLoadTemperature.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructurallinearaction.htm"
    },
    "IfcStructuralLinearActionVarying": {
        "attributes": {
            "SubsequentAppliedLoads": "A list containing load values which are assigned to the position defined through the shape aspect. The first load is already defined by the inherited attribute AppliedLoad and shall not be contained in this list.",
            "VaryingAppliedLoadLocation": "A shape aspect, containing a list of shape representations, each defining either one Cartesian point or one point on curve (by parameter values) which are needed to provide the positions of the VaryingAppliedLoads. The values contained in the list of IfcShapeAspect.ShapeRepresentations correspond to the values at the same position in the list VaryingAppliedLoads.",
            "VaryingAppliedLoads": "Derived list of all varying applied loads by pushing the inherited AppliedLoad value to the beginning of the list of SubsequentAppliedLoads. IfcAddToBeginOfList(SELF\\IfcStructuralActivity.AppliedLoad, SubsequentAppliedLoads)"
        },
        "description": "Instances of the entity IfcStructuralLinearActionVarying are used to define varying linear actions. IfcStructuralLinearActionVarying inherits the needed attributes and applicable structural load types from its superclass IfcStructuralLinearAction.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructurallinearactionvarying.htm"
    },
    "IfcStructuralLoad": {
        "attributes": {
            "Name": "Optionally defines a name for this load."
        },
        "description": "The abstract entity IfcStructuralLoad is the supertype of all loads which can be defined (actions or reactions, as well as dynamic or static).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralload.htm"
    },
    "IfcStructuralLoadGroup": {
        "attributes": {
            "ActionSource": "Source of actions in the group. Normally needed if 'PredefinedType' specifies a LOAD_CASE.",
            "ActionType": "Type of actions in the group. Normally needed if 'PredefinedType' specifies a LOAD_COMBINATION_GROUP.",
            "Coefficient": "Load factor. If omitted, a factor is not yet known or not specified. A load factor of 1.0 shall be explicitly exported as Coefficient = 1.0.",
            "LoadGroupFor": "Analysis models in which this load group is used.",
            "Purpose": "Description of the purpose of this instance. Among else, possible values of the Purpose of load combinations are 'SLS', 'ULS', 'ALS' to indicate serviceability, ultimate, or accidental limit state.",
            "SourceOfResultGroup": "Results which were computed using this load group."
        },
        "description": "The entity IfcStructuralLoadGroup is used to structure the physical impacts. By using the grouping features inherited from IfcGroup, instances of IfcStructuralAction (or its subclasses) and of IfcStructuralLoadGroup can be used to define load groups, load cases and load combinations. An optional coefficient can be provided to represent safety factors known from several codes of practice. (see also IfcLoadGroupTypeEnum)",
        "predefined_types": {
            "LOAD_CASE": "Groups LOAD_GROUPs and instances of subtypes of _IfcStructuralAction_.\n      It should be used as a container for loads with the same origin.",
            "LOAD_COMBINATION": "An intermediate level between LOAD_CASE and LOAD_COMBINATION.  This level is obsolete and deprecated.  Before the introduction of _IfcRelAssignsToGroupByFactor_, the purpose of this level was to provide a factor with which one or more LOAD_CASEs occur in a LOAD_COMBINATION.",
            "LOAD_COMBINATION_GROUP": "",
            "LOAD_GROUP": "Groups instances of subtypes of _IfcStructuralAction_.  It shall be used as a container for loads grouped together for specific purposes, such as loads which are part of a special load pattern.",
            "NOTDEFINED": "The grouping level is not yet known.",
            "USERDEFINED": "A grouping level which does not follow the standard hierarchy of load group types."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralloadgroup.htm"
    },
    "IfcStructuralLoadLinearForce": {
        "attributes": {
            "LinearForceX": "Linear force value in x-direction.",
            "LinearForceY": "Linear force value in y-direction.",
            "LinearForceZ": "Linear force value in z-direction.",
            "LinearMomentX": "Linear moment about the x-axis.",
            "LinearMomentY": "Linear moment about the y-axis.",
            "LinearMomentZ": "Linear moment about the z-axis."
        },
        "description": "An instance of the entity IfcStructuralLoadLinearForce shall be used to define actions on curves.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadlinearforce.htm"
    },
    "IfcStructuralLoadPlanarForce": {
        "attributes": {
            "PlanarForceX": "Planar force value in x-direction.",
            "PlanarForceY": "Planar force value in y-direction.",
            "PlanarForceZ": "Planar force value in z-direction."
        },
        "description": "An instance of the entity IfcStructuralLoadPlanarForce shall be used to define actions on faces.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadplanarforce.htm"
    },
    "IfcStructuralLoadSingleDisplacement": {
        "attributes": {
            "DisplacementX": "Displacement in x-direction.",
            "DisplacementY": "Displacement in y-direction.",
            "DisplacementZ": "Displacement in z-direction.",
            "RotationalDisplacementRX": "Rotation about the x-axis.",
            "RotationalDisplacementRY": "Rotation about the y-axis.",
            "RotationalDisplacementRZ": "Rotation about the z-axis."
        },
        "description": "Instances of the entity IfcStructuralLoadSingleDisplacement shall be used to define the displacements of an action operating on a single point.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadsingledisplacement.htm"
    },
    "IfcStructuralLoadSingleDisplacementDistortion": {
        "attributes": {
            "Distortion": "The distortion curvature given to the displacement load."
        },
        "description": "Instances of the entity IfcStructuralLoadSingleForceWarping, as a subtype of IfcStructuralLoadSingleForce, shall be used to define an action operation on a single point. In addition to forces and moments defined by its supertype a warping moment can be defined.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadsingledisplacementdistortion.htm"
    },
    "IfcStructuralLoadSingleForce": {
        "attributes": {
            "ForceX": "Force value in x-direction.",
            "ForceY": "Force value in y-direction.",
            "ForceZ": "Force value in z-direction.",
            "MomentX": "Moment about the x-axis.",
            "MomentY": "Moment about the y-axis.",
            "MomentZ": "Moment about the z-axis."
        },
        "description": "Instances of the entity IfcStructuralLoadSingleForce shall be used to define the forces and moments of an action operating on a single point.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadsingleforce.htm"
    },
    "IfcStructuralLoadSingleForceWarping": {
        "attributes": {
            "WarpingMoment": "The warping moment at the point load."
        },
        "description": "Instances of the entity IfcStructuralLoadSingleForceWarping, as a subtype of IfcStructuralLoadSingleForce, shall be used to define an action operation on a single point. In addition to forces and moments defined by its supertype a warping moment can be defined.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadsingleforcewarping.htm"
    },
    "IfcStructuralLoadStatic": {
        "description": "The abstract entity IfcStructuralLoadStatic is the supertype of all static loads (actions or reactions) which can be defined.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadstatic.htm"
    },
    "IfcStructuralLoadTemperature": {
        "attributes": {
            "DeltaT_Constant": "Temperature change which is applied to the complete section of the structural member. A positive value describes an increase in temperature.",
            "DeltaT_Y": "Temperature change which is applied to the outer fiber of the positive Y-direction. A positive value describes an increase in temperature.",
            "DeltaT_Z": "Temperature change which is applied to the outer fiber of the positive Z-direction. A positive value describes an increase in temperature."
        },
        "description": "An instance of the entity IfcStructuralLoadTemperature shall be used to define actions which are caused by a temperature change. The change of temperature is given with a constant value which is applied to the complete section and values for the outer fibre of the positive Y and Z directions.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralloadresource/lexical/ifcstructuralloadtemperature.htm"
    },
    "IfcStructuralMember": {
        "attributes": {
            "ConnectedBy": "Inverse relationship to all structural connections (i.e. to supports or connecting elements) which are defined for this structural member.",
            "ReferencesElement": "Inverse link to the relationship object, that connects a physical element to this structural member (the element of which this structural member is the analytical idealization)."
        },
        "description": "Definition from IAI: The abstract entity IfcStructuralMember is the superclass of all structural elements representing the structural behavior of building elements. A further differentiation is made for structural curve members and structural face members (see IfcStructuralCurveMember and IfcStructuralFaceMember). Structural members can have ",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralmember.htm"
    },
    "IfcStructuralPlanarAction": {
        "attributes": {
            "ProjectedOrTrue": "Defines if the load values are given by using the length of the member on which they act (true length) or by using the projected length resulting from the loaded member and the global project coordinate system. It is only considered if the global project coordinate system is used, and if the action is of type IfcStructuralLinearAction or IfcStructuralPlanarAction."
        },
        "description": "Instances of the entity IfcStructuralPlanarAction are used to define constant planar actions. Structural loads applicable to planar actions are IfcStructuralLoadPlanarForce and IfcStructuralLoadTemperature.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralplanaraction.htm"
    },
    "IfcStructuralPlanarActionVarying": {
        "attributes": {
            "SubsequentAppliedLoads": "A list containing load values which are assigned to the position defined through the shape aspect. The first load is already defined by the inherited attribute AppliedLoad and shall not be contained in this list.",
            "VaryingAppliedLoadLocation": "A shape aspect, containing a list of shape representations, each defining either one Cartesian point or one point on curve (by parameter values) which are needed to provide the positions of the VaryingAppliedLoads. The values contained in the list of IfcShapeAspect.ShapeRepresentations correspond to the values at the same position in the list VaryingAppliedLoads.",
            "VaryingAppliedLoads": "Derived list of all varying applied loads by pushing the inherited AppliedLoad value to the beginning of the list of SubsequentAppliedLoads. IfcAddToBeginOfList(SELF\\IfcStructuralActivity.AppliedLoad, SubsequentAppliedLoads)"
        },
        "description": "Instances of the entity IfcStructuralPlanarActionVarying are used to define varying planar actions. IfcStructuralPlanarActionVarying inherits the needed attributes and applicable structural load types from its superclass IfcStructuralLinearAction.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralplanaractionvarying.htm"
    },
    "IfcStructuralPointAction": {
        "description": "Instances of the entity IfcStructuralPointAction are used to define point actions. Structural loads applicable to point actions are IfcStructuralLoadSingleForce (and subtype), and IfcStructuralLoadSingleDisplacement (and subtype).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralpointaction.htm"
    },
    "IfcStructuralPointConnection": {
        "description": "Instances of the entity IfcStructuralPointConnection shall be used to describe structural nodes or point supports. All values defined by AppliedCondition are given within the local coordinate system, which is defined by this instance.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralpointconnection.htm"
    },
    "IfcStructuralPointReaction": {
        "description": "Instances of the entity IfcStructuralPointReaction are used to define point reactions. IfcStructuralPointReaction inherits all needed attributes from its superclass IfcStructuralReaction.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralpointreaction.htm"
    },
    "IfcStructuralProfileProperties": {
        "attributes": {
            "CentreOfGravityInX": "Location of the profile's centre of gravity in the geometric X direction. The _CentreOfGravityInX_ is measured in the global length unit as defined at _IfcProject.UnitsInContext_.",
            "CentreOfGravityInY": "Location of the profile's centre of gravity in the geometric Y direction. The _CentreOfGravityInY_ is measured in the global length unit as defined at _IfcProject.UnitsInContext_.",
            "MaximumSectionModulusY": "Bending resistance about Y-axis of profile coordinate system at maximum Z-ordinate. Usually measured in [mm3].",
            "MaximumSectionModulusZ": "Bending resistance about Z-axis of profile coordinate system at maximum Y-ordinate. Usually measured in [mm3].",
            "MinimumSectionModulusY": "Bending resistance about Y-axis of profile coordinate system at minimum Z-ordinate. Usually measured in [mm3].",
            "MinimumSectionModulusZ": "Bending resistance about Z-axis of profile coordinate system at minimum Y-ordinate. Usually measured in [mm3].",
            "MomentOfInertiaY": "Moment of inertia about Y-axis of profile coordinate system. Usually measured in [mm4].",
            "MomentOfInertiaYZ": "Moment of inertia about Y and Z-axes of profile coordinate system. Usually measured in [mm4].",
            "MomentOfInertiaZ": "Moment of inertia about Z-axis of profile coordinate system. Usually measured in [mm4].",
            "ShearCentreY": "Location of the profile's shear centre in the structural Y direction. Mapped on IFC profile coordinate system it is the offset in the direction of the negative X axis. The offset is relative to the center of gravity.   The _ShearCentreY_ is measured in the global length unit as defined at _IfcProject.UnitsInContext_.",
            "ShearCentreZ": "Location of the profile's shear centre in the structural Z direction. Mapped on IFC profile coordinate system it is the offset in the direction of the negative Y axis. The offset is relative to the center of gravity.   The _ShearCentreZ_ is measured in the global length unit as defined at _IfcProject.UnitsInContext_.",
            "ShearDeformationAreaY": "Area of the profile for calculating the shear deformation for a shear force parallel to the profile's Y-axis. Usually measured in [mm2].",
            "ShearDeformationAreaZ": "Area of the profile for calculating the shear deformation for a shear force parallel to the profile's Z-axis. Usually measured in [mm2].",
            "TorsionalConstantX": "Torsional constant about X-axis of profile coordinate system. Usually measured in [mm4].",
            "TorsionalSectionModulus": "Torsional resistance (about the profiles X-axis). Usually measured in [mm3].",
            "WarpingConstant": "Warping constant of the profile for torsional action. Usually measured in [mm6]."
        },
        "description": "Definition from IAI: This is a collection of structural properties applicable to all linear structural members having a profile definition. For the structural profile properties a further material dependent specialization is given for taking into account specific profile properties applicable only in the context of a specific building material.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcstructuralprofileproperties.htm"
    },
    "IfcStructuralReaction": {
        "attributes": {
            "Causes": "Optional reference to instances of IfcStructuralAction which directly depend on this reaction. This reference is only needed if dependencies between structural analysis models must be captured."
        },
        "description": "A structural reaction is a structural activity that results from a structural action imposed to a structural item or building element. A support is an example for a structural reaction.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralreaction.htm"
    },
    "IfcStructuralResultGroup": {
        "attributes": {
            "IsLinear": "This Boolean value allows to easily recognize if a linear analysis has been applied (allowing the superposition of analysis results), or vice versa.",
            "ResultForLoadGroup": "Reference to an instance of IfcStructuralLoadGroup for which this instance represents the result.",
            "ResultGroupFor": "Reference to an instance of IfcStructuralAnalysisModel for which this instance captures a result.",
            "TheoryType": "Specifies the analysis theory used to obtain the respective results."
        },
        "description": "Instances of the entity IfcStructuralResultGroup are used to group results of structural analysis calculations and to capture the connection to the underlying basic load group. The basic functionality for grouping inherited from IfcGroup is used to collect instances from IfcStructuralReaction or its respective subclasses.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralresultgroup.htm"
    },
    "IfcStructuralSteelProfileProperties": {
        "attributes": {
            "PlasticShapeFactorY": "Ratio of plastic versus elastic bending moment capacity (about y-axis) of the profile.",
            "PlasticShapeFactorZ": "Ratio of plastic versus elastic bending moment capacity (about z-axis) of the profile.",
            "ShearAreaY": "Area of the profile for calculating the shear stress for a shear force parallel to the profile's Y-axis. Usually measured in [mm2].",
            "ShearAreaZ": "Area of the profile for calculating the shear stress for a shear force parallel to the profile's Z-axis. Usually measured in [mm2]."
        },
        "description": "This is a collection of structural properties applicable to all linear structural members having a profile definition. These structural members are made of steel (or other metalic and isotropic material).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofilepropertyresource/lexical/ifcstructuralsteelprofileproperties.htm"
    },
    "IfcStructuralSurfaceConnection": {
        "description": "Instances of the entity IfcStructuralSurfaceConnection are used to describe structural supports provided by planar elements. All values defined by AppliedCondition are given within the local coordinate system, which is defined by this instance.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfaceconnection.htm"
    },
    "IfcStructuralSurfaceMember": {
        "attributes": {
            "Thickness": "Defines the typically understood thickness of the structural face member, i.e. the smallest spatial dimension of the element."
        },
        "description": "Instances of the entity IfcStructuralSurfaceMember shall be used to describe planar structural elements.",
        "predefined_types": {
            "BENDING_ELEMENT": "",
            "MEMBRANE_ELEMENT": "",
            "NOTDEFINED": "",
            "SHELL": "",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfacemember.htm"
    },
    "IfcStructuralSurfaceMemberVarying": {
        "attributes": {
            "SubsequentThickness": "Defines the variable thickness of the structural face member using two or more subsequent and additional thickness values. The first thickness value is already given by the inherited Thickness value and shall not be included in the list.",
            "VaryingThickness": "Derived list of all varying thickness values by pushing the inherited starting thickness to the beginning of the list of SubsequentThickness. IfcAddToBeginOfList(SELF\\IfcStructuralSurfaceMember.Thickness, SubsequentThickness)",
            "VaryingThicknessLocation": "A shape aspect, containing a list of shape representations, each defining either one Cartesian point or one point on surface (by parameter values) which are needed to provide the positions of the VaryingThickness. The values contained in the list of IfcShapeAspect.ShapeRepresentations correspond to the values at the same position in the list VaryingThickness. The locations shall be along the outer bounds of the face (or surface) only."
        },
        "description": "Instances of the entity IfcStructuralSurfaceMemberVarying shall be used to describe planar structural elements with a varying thickness.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralanalysisdomain/lexical/ifcstructuralsurfacemembervarying.htm"
    },
    "IfcStructuredDimensionCallout": {
        "description": "The structured dimension callout represents a special type of a draughting callout, which identifies the various components of the dimension text. This is done by ensuring the correct Name attribute values for the annotation text occurrences used within the callout.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcstructureddimensioncallout.htm"
    },
    "IfcStyleModel": {
        "description": "The IfcStyleModel represents the concept of a particular presentation style defined for a material (or other characteristic) of a product or a product component within a representation context. This representation context may (but has not to be) a geometric representation context. ",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcstylemodel.htm"
    },
    "IfcStyledItem": {
        "attributes": {
            "Item": "A geometric representation item to which the style is assigned.",
            "Name": "The word, or group of words, by which the styled item is referred to.",
            "Styles": "Representation style assignments which are assigned to an item. NOTE: In current IFC release only one presentation style assignment shall be assigned."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The styled item is an assignment of style for presentation to a geometric representation item as it is used in a representation.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcstyleditem.htm"
    },
    "IfcStyledRepresentation": {
        "description": "Definition from IAI: The IfcStyledRepresentation represents the concept of a styled presentation being a representation of a product or a product component, like material. within a representation context. This representation context does not need to be (but may be) a geometric representation context.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifcstyledrepresentation.htm"
    },
    "IfcSubContractResource": {
        "attributes": {
            "JobDescription": "The description of the jobs that this subcontract should complete.",
            "SubContractor": "The actor performing the role of the subcontracted resource."
        },
        "description": "An IfcSubContractResource is a construction resource needed in a construction process that represents a type of sub-contractor.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcconstructionmgmtdomain/lexical/ifcsubcontractresource.htm"
    },
    "IfcSubedge": {
        "attributes": {
            "ParentEdge": "The Edge, or Subedge, which contains the Subedge."
        },
        "description": "Definition from ISO/DIS 10303-42:1999(E): A subedge is an edge whose domain is a connected portion of the domain of an existing edge. The topological constraints on a subedge are the same as those on an edge.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcsubedge.htm"
    },
    "IfcSurface": {
        "description": "Definition from ISO/CD 10303-42:1992: A surface can be envisioned as a set of connected points in 3-dimensional space which is always locally 2-dimensional, but need not be a manifold.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcsurface.htm"
    },
    "IfcSurfaceCurveSweptAreaSolid": {
        "attributes": {
            "Directrix": "The curve used to define the sweeping operation. The solid is generated by sweeping the SELF\\IfcSweptAreaSolid.SweptArea along the Directrix.",
            "EndParam": "The parameter value on the Directrix at which the sweeping operation ends.",
            "ReferenceSurface": "The surface containing the Directrix.",
            "StartParam": "The parameter value on the Directrix at which the sweeping operation commences."
        },
        "description": "Definition from ISO/DIS 10303-42:1999(E): A surface curve swept area solid is a type of swept area solid which is the result of sweeping a face along a Directrix lying on a ReferenceSurface. The orientation of the SweptArea is related to the direction of the surface normal.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcsurfacecurvesweptareasolid.htm"
    },
    "IfcSurfaceOfLinearExtrusion": {
        "attributes": {
            "Depth": "The depth of the extrusion, it determines the parameterization.",
            "ExtrudedDirection": "The direction of the extrusion.",
            "ExtrusionAxis": "The extrusion axis defined as vector. IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector (ExtrudedDirection, Depth)"
        },
        "description": "Definition from ISO/CD 10303-42:1992: This surface is a simple swept surface or a generalized cylinder obtained by sweeping a curve in a given direction. The parameterization is as follows where the curve has a parameterization l(u):",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcsurfaceoflinearextrusion.htm"
    },
    "IfcSurfaceOfRevolution": {
        "attributes": {
            "AxisLine": "The line coinciding with the axis of revolution. IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcCurve() || IfcLine(AxisPosition.Location,    IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector(AxisPosition.Z,1.0))",
            "AxisPosition": "A point on the axis of revolution and the direction of the axis of revolution."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A surface of revolution (IfcSurfaceOfRevolution) is the surface obtained by rotating a curve one complete revolution about an axis. The data shall be interpreted as below.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcsurfaceofrevolution.htm"
    },
    "IfcSurfaceStyle": {
        "attributes": {
            "Side": "An indication of which side of the surface to apply the style.",
            "Styles": "A collection of different surface styles."
        },
        "description": "An assignment of one or many surface style elements to a surface, defined by subtypes of IfcSurface, IfcFaceBasedSurfaceModel, IfcShellBasedSurfaceModel, or by subtypes of IfcSolidModel. The positive direction of the surface normal relates to the positive side. In case of solids the outside of the solid is to be taken as positive side.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestyle.htm"
    },
    "IfcSurfaceStyleLighting": {
        "attributes": {
            "DiffuseReflectionColour": "The degree of diffusion of the reflected light. In the case of specular surfaces there is no diffusion. The greater the diffusing power of the reflecting surface, the smaller the specular component of the reflected light, up to the point where only diffuse light is produced. A value of 1 means totally diffuse for that colour part of the light.  > The factor can be measured physically and has three ratios for the red, green and blue part of the light.",
            "DiffuseTransmissionColour": "The degree of diffusion of the transmitted light. In the case of completely transparent materials there is no diffusion. The greater the diffusing power, the smaller the direct component of the transmitted light, up to the point where only diffuse light is produced.A value of 1 means totally diffuse for that colour part of the light. > The factor can be measured physically and has three ratios for the red, green and blue part of the light.",
            "ReflectanceColour": "A coefficient that determines the extent that the light falling onto a surface is fully or partially reflected.  > The factor can be measured physically and has three ratios for the red, green and blue part of the light.",
            "TransmissionColour": "Describes how the light falling on a body is totally or partially transmitted.  > The factor can be measured physically and has three ratios for the red, green and blue part of the light."
        },
        "description": "IfcSurfaceStyleLighting is a container class for properties for calculation of physically exact illuminance related to a particular surface style.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestylelighting.htm"
    },
    "IfcSurfaceStyleRefraction": {
        "attributes": {
            "DispersionFactor": "The Abbe constant given as a fixed ratio between the refractive indices of the material at different wavelengths. A low Abbe number means a high dispersive power. In general this translates to a greater angular spread of the emergent spectrum.",
            "RefractionIndex": "The index of refraction for all wave lengths of light. The refraction index is the ratio between the speed of light in a vacuum and the speed of light in the medium. E.g. glass has a refraction index of 1.5, whereas water has an index of 1.33"
        },
        "description": "IfcSurfaceStyleRefraction extends the surface style lighting, or the surface style rendering definition for properties for calculation of physically exact illuminance by adding seldomly used properties. Currently this includes the refraction index (by which the light ray refracts when passing through a prism) and the dispersion factor (or Abbe constant) which takes into account the wavelength dependency of the refraction.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestylerefraction.htm"
    },
    "IfcSurfaceStyleRendering": {
        "attributes": {
            "DiffuseColour": "The diffuse part of the reflectance equation can be given as either a colour or a scalar factor. The diffuse colour field reflects all light sources depending on the angle of the surface with respect to the light source. The more directly the surface faces the light, the more diffuse light reflects. The diffuse factor field specifies how much diffuse light from light sources this surface shall reflect. Diffuse light depends on the angle of the surface with respect to the light source. The more directly the surface faces the light, the more diffuse light reflects. The diffuse colour is then defined by surface colour \\* diffuse factor.",
            "DiffuseTransmissionColour": "The diffuse transmission part of the reflectance equation can be given as either a colour or a scalar factor. It only applies to materials whose Transparency field is greater than zero. The diffuse transmission colour specifies how much diffuse light is reflected at the opposite side of the material surface. The diffuse transmission factor field specifies how much diffuse light from light sources this surface shall reflect on the opposite side of the material surface. The diffuse transmissive colour is then defined by surface colour \\* diffuse transmissive factor.",
            "ReflectanceMethod": "Identifies the predefined types of reflectance method from which the method required may be set.",
            "ReflectionColour": "The reflection (or mirror) part of the reflectance equation can be given as either a colour or a scalar factor. Applies to \"glass\" and \"mirror\" reflection models. The reflection colour specifies the contribution made by light from the mirror direction, i.e. light being reflected from the surface. The reflection factor specifies the amount of contribution made by light from the mirror direction. The reflection colour is then defined by surface colour \\* reflection factor.",
            "SpecularColour": "The specular part of the reflectance equation can be given as either a colour or a scalar factor. The specular colour determine the specular highlights (e.g., the shiny spots on an apple). When the angle from the light to the surface is close to the angle from the surface to the viewer, the specular colour is added to the diffuse and ambient colour calculations. The specular factor defines the specular part, the specular colour is then defined by surface colour \\* specular factor.",
            "SpecularHighlight": "The exponent or roughness part of the specular reflectance.",
            "TransmissionColour": "The transmissive part of the reflectance equation can be given as either a colour or a scalar factor. It only applies to materials which Transparency field is greater than zero. The transmissive colour field specifies the colour that passes through a transparant material (like the colour that shines through a glass). The transmissive factor defines the transmissive part, the transmissive colour is then defined by surface colour \\* transmissive factor.",
            "Transparency": "Definition from ISO/CD 10303-46: The degree of transparency is indicated by the percentage of light traversing the surface. Definition from VRML97 - ISO/IEC 14772-1:1997: The transparency field specifies how \"clear\" an object is, with 1.0 being completely transparent, and 0.0 completely opaque. If not given, the value 0.0 (opaque) is assumed."
        },
        "description": "IfcSurfaceStyleRendering holds the properties for visualization related to a particular surface side style.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestylerendering.htm"
    },
    "IfcSurfaceStyleShading": {
        "attributes": {
            "SurfaceColour": "The colour used to render the surface. The surface colour for visualisation is defined by specifying the intensity of red, green and blue."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The surface style rendering allows the realistic visualization of surfaces referring to rendering techniques based on the laws of physics and mathematics.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestyleshading.htm"
    },
    "IfcSurfaceStyleWithTextures": {
        "attributes": {
            "Textures": "The textures applied to the surface. Only one image map with the same image map type shall be applied."
        },
        "description": "Definition from IAI: The entity IfcSurfaceStyleWithTextures allows for the assignment of image textures to surface styles. These image textures can be applied repeating across the surface or mapped with a particular scale upon the surface.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacestylewithtextures.htm"
    },
    "IfcSurfaceTexture": {
        "attributes": {
            "RepeatS": "The RepeatS field specifies how the texture wraps in the S direction. If RepeatS is TRUE (the default), the texture map is repeated outside the [0.0, 1.0] texture coordinate range in the S direction so that it fills the shape. If repeatS is FALSE, the texture coordinates are clamped in the S direction to lie within the [0.0, 1.0] range.",
            "RepeatT": "The RepeatT field specifies how the texture wraps in the T direction. If RepeatT is TRUE (the default), the texture map is repeated outside the [0.0, 1.0] texture coordinate range in the T direction so that it fills the shape. If repeatT is FALSE, the texture coordinates are clamped in the T direction to lie within the [0.0, 1.0] range.",
            "TextureTransform": "These parameters support changes to the size, orientation, and position of textures on shapes. Note that these operations appear reversed when viewed on the surface of geometry. For example, a scale value of (2 2) will scale the texture coordinates and have the net effect of shrinking the texture size by a factor of 2 (texture coordinates are twice as large and thus cause the texture to repeat). A translation of (0.5 0.0) translates the texture coordinates +.5 units along the S-axis and has the net effect of translating the texture -0.5 along the S-axis on the geometry's surface. A rotation of PI/2 of the texture coordinates results in a -PI/2 rotation of the texture on the geometry.",
            "TextureType": "Identifies the predefined types of image map from which the type required may be set."
        },
        "description": "Definition from IAI: An IfcSurfaceTexture provides a 2-dimensional image-based texture map. It can either be given by referencing an external image file through an URL reference (IfcImageTexture), or by explicitly including an array of pixels (IfcPixelTexture).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsurfacetexture.htm"
    },
    "IfcSweptAreaSolid": {
        "attributes": {
            "Position": "Position coordinate system for the swept area.",
            "SweptArea": "The surface defining the area to be swept. It is given as a profile definition within the xy plane of the position coordinate system."
        },
        "description": "Definition from ISO/CD 10303-42:1992: The swept area solid entity collects the entities which are defined procedurally by sweeping action on planar bounded surfaces. The position is space of the swept solid will be dependent upon the position of the swept area. The swept area will be a face of the resulting swept area solid, except for the case of a revolved area solid with angle equal to 2 p (or 360 degrees).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcsweptareasolid.htm"
    },
    "IfcSweptDiskSolid": {
        "attributes": {
            "Directrix": "The curve used to define the sweeping operation. The solid is generated by sweeping a circular disk along the directrix.",
            "EndParam": "The parameter value on the directrix at which the sweeping operation ends.",
            "InnerRadius": "This attribute is optional, if present it defines the radius of a circular hole in the centre of the disk.",
            "Radius": "The radius of the circular disk to be swept along the directrix.",
            "StartParam": "The parameter value on the directrix at which the sweeping operation commences."
        },
        "description": "Definition from ISO/FDIS 10303-42-ed3:2002: A swept disk solid is the solid produced by sweeping a circular disk along a three dimensional curve. During the sweeping operation the normal to the plane of the circular disk is in the direction of the tangent to the directrix curve and the center of the disk lies on the directrix. The circular disk may, optionally, have a central hole, in this case the resulting solid has a through hole, or, an internal void when the directrix forms a close curve.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricmodelresource/lexical/ifcsweptdisksolid.htm"
    },
    "IfcSweptSurface": {
        "attributes": {
            "Dim": "The space dimensionality of this class, derived from the dimensionality of the Position. Position.Dim",
            "Position": "Position coordinate system for the placement of the profile within the xy plane of the axis placement.",
            "SweptCurve": "The curve to be swept in defining the surface. The curve is defined as a profile within the position coordinate system."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A swept surface is one that is constructed by sweeping a curve along another curve.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcsweptsurface.htm"
    },
    "IfcSwitchingDeviceType": {
        "description": "An IfcSwitchingDeviceType defines a particular type of switch which is a mechanically operated contactor.",
        "predefined_types": {
            "CONTACTOR": "An electrical device used to control the flow of power in a circuit on or off.",
            "EMERGENCYSTOP": "An emergency stop device acts to remove as quickly as possible any danger that may have arisen unexpectedly.",
            "NOTDEFINED": "Undefined type.",
            "STARTER": "A starter is a switch which in the closed position controls the application of power to an electrical device.",
            "SWITCHDISCONNECTOR": "A switch disconnector is a switch which in the open position satisfies the isolating requirements specified for a disconnector.",
            "TOGGLESWITCH": "A toggle switch has two positions, and may enable or isolate electrical power or other setting (according to the switched port type).",
            "USERDEFINED": "User-defined type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifcswitchingdevicetype.htm"
    },
    "IfcSymbolStyle": {
        "attributes": {
            "StyleOfSymbol": "The style applied to the symbol for its visual appearance."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The symbol style is the presentation style that indicates the presentation of annotation symbols.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifcsymbolstyle.htm"
    },
    "IfcSystem": {
        "attributes": {
            "ServicesBuildings": "Reference to the ~~building~~ spatial structure via the objectified relationship _IfcRelServicesBuildings_, which is serviced by the system."
        },
        "description": "Organized combination of related parts within an AEC product, composed for a common purpose or function or to provide a service. System is essentially a functionally related aggregation of products. The grouping relationship to one or several instances of IfcProduct (the system members) is handled by IfcRelAssignsToGroup.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcsystem.htm"
    },
    "IfcSystemFurnitureElementType": {
        "description": "An IfcSystemFurnitureElementType defines a particular type of component or element of systems or modular furniture.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedfacilitieselements/lexical/ifcsystemfurnitureelementtype.htm"
    },
    "IfcTShapeProfileDef": {
        "attributes": {
            "CentreOfGravityInY": "Location of centre of gravity along the x axis measured from the center of the bounding box.",
            "Depth": "Web lengths, see illustration above (= h).",
            "FilletRadius": "Fillet radius according the above illustration (= r1). If it is not given, zero is assumed.",
            "FlangeEdgeRadius": "Edge radius according the above illustration (= r2). If it is not given, zero is assumed.",
            "FlangeSlope": "Slope of web of the profile. If it is not given, zero is assumed.",
            "FlangeThickness": "Constant wall thickness of flange (= tg).",
            "FlangeWidth": "Flange lengths, see illustration above (= b).",
            "WebEdgeRadius": "Edge radius according the above illustration (= r3). If it is not given, zero is assumed.",
            "WebSlope": "Slope of flange of the profile. If it is not given, zero is assumed.",
            "WebThickness": "Constant wall thickness of web (= ts)."
        },
        "description": "Definition from IAI: The IfcTShapeProfileDef defines a section profile that provides the defining parameters of a T-shaped section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the ~~gravity~~ bounding box.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifctshapeprofiledef.htm"
    },
    "IfcTable": {
        "attributes": {
            "Name": "A unique name which is intended to describe the usage of the Table.",
            "NumberOfCellsInRow": "The number of cells in each row, this complies to the number of columns in a table. See WR2 that ensures that each row has the same number of cells. The actual value is derived from the first member of the Rows list. HIINDEX(Rows[1].RowCells)",
            "NumberOfDataRows": "The number of rows in a table that contains data, i.e. total number of rows minus number of heading rows in table. SIZEOF(QUERY( Temp <* Rows | NOT(Temp.IsHeading)))",
            "NumberOfHeadings": "The number of headings in a table. This is restricted by WR3 to max. one. SIZEOF(QUERY( Temp <* Rows | Temp.IsHeading))",
            "Rows": "Reference to information content of rows."
        },
        "description": "A data structure for the provision of information in the form of rows and columns. Each instance may have a heading row with titles or descriptions for each column. The rows of information are stored as a list of IfcTableRow objects.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcutilityresource/lexical/ifctable.htm"
    },
    "IfcTableRow": {
        "attributes": {
            "IsHeading": "Flag which identifies if the row is a heading row or a row which contains row values. NOTE - If the row is a heading, the flag takes the value = TRUE.",
            "OfTable": "Reference to the IfcTable, in which the IfcTableRow is defined (or contained).",
            "RowCells": "The value of information by row and column using the units defined. NOTE - The row value identifies both the actual value and the units in which it is recorded. Each cell (unique row and column) may have a different value AND different units. If the row is a heading row, then the row values are strings defined by the IfcString."
        },
        "description": "The information content of each row within the table (other than the heading row). A table contains a number of rows which record information concerning the instance of the type of information recorded within the table.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcutilityresource/lexical/ifctablerow.htm"
    },
    "IfcTankType": {
        "description": "The element type IfcTankType defines a list of commonly shared property set definitions of a tank and an optional set of product representations. It is used to define a tank specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "EXPANSION": "A closed container used in a closed fluid distribution system to mitigate the effects of thermal expansion or water hammer. The tank is typically constructed with a diaphragm dividing the tank into two sections, with fluid on one side of the diaphragm and air on the other. One example application is when connected to the primary circuit of a hot water system to accommodate the increase in volume of the water when it is heated.",
            "NOTDEFINED": "Undefined tank type.",
            "PREFORMED": "",
            "PRESSUREVESSEL": "A closed container used for storing fluids or gases at a pressure different from the ambient pressure. A pressure vessel is typically rated by an authority having jurisdiction for the operational pressure.",
            "SECTIONAL": "",
            "USERDEFINED": "User-defined tank type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifctanktype.htm"
    },
    "IfcTask": {
        "attributes": {
            "IsMilestone": "Identifies whether a task is a milestone task (=TRUE) or not (= FALSE). NOTE: In small project planning applications, a milestone task may be understood to be a task having no duration. As such, it represents a singular point in time.",
            "Priority": "A value that indicates the relative priority of the task (in comparison to the priorities of other tasks).",
            "Status": "Current status of the task. NOTE: Particular values for status are not specified, these should be determined and agreed by local usage. Examples of possible status values include 'Not Yet Started', 'Started', 'Completed'.",
            "TaskId": "An identifying designation given to a task.",
            "WorkMethod": "The method of work used in carrying out a task."
        },
        "description": "An IfcTask is an identifiable unit of work to be carried out independently of any other units of work in a construction project.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifctask.htm"
    },
    "IfcTelecomAddress": {
        "attributes": {
            "ElectronicMailAddresses": "The list of Email addresses at which Email messages may be received.",
            "FacsimileNumbers": "The list of fax numbers at which fax messages may be received.",
            "PagerNumber": "The pager number at which paging messages may be received.",
            "TelephoneNumbers": "The list of telephone numbers at which telephone messages may be received.",
            "WWWHomePageURL": "The world wide web address at which the preliminary page of information for the person or organization can be located. > NOTE: Information on the world wide web for a person or organization may be separated  into a number of pages and across a number of host sites, all of which may be linked together. It is assumed that  all such information may be referenced from a single page that is termed the home page for that person or organization."
        },
        "description": "Address to which telephone, electronic mail and other forms of telecommunications should be addressed.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcactorresource/lexical/ifctelecomaddress.htm"
    },
    "IfcTendon": {
        "attributes": {
            "AnchorageSlip": "The deformation of an anchor or slippage of tendons when the prestressing device is released.",
            "CrossSectionArea": "The effective cross-section area of the tendon.",
            "FrictionCoefficient": "The friction coefficient for the bond between the tendon and the surrounding concrete.",
            "MinCurvatureRadius": "The smallest curvature radius calculated on the whole effective length of the tendon where the tension properties are still valid.",
            "NominalDiameter": "The nominal diameter defining the cross-section size of the tendon.",
            "PreStress": "The prestress to be applied on the tendon.",
            "TensionForce": "The maximum allowed tension force that can be applied on the tendon."
        },
        "description": "A steel element such as a wire, cable, bar, rod, or strand used to impart prestress to concrete when the element is tensioned.",
        "predefined_types": {
            "BAR": "The tendon is configured as a bar.",
            "COATED": "The tendon is coated.",
            "NOTDEFINED": "The type of tendon is not defined.",
            "STRAND": "The tendon is a strand.",
            "USERDEFINED": "The type of tendon is user defined.",
            "WIRE": "The tendon is a wire."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifctendon.htm"
    },
    "IfcTendonAnchor": {
        "description": "In prestressed or posttensioned concrete, the end connection for the tendons.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcstructuralelementsdomain/lexical/ifctendonanchor.htm"
    },
    "IfcTerminatorSymbol": {
        "attributes": {
            "AnnotatedCurve": "The curve being annotated by the terminator symbol."
        },
        "description": "A terminator symbol is a special type of an annotated symbol which is assigned to a curve to indicate a direction, origin, target, or any other associated meaning.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdimensioningresource/lexical/ifcterminatorsymbol.htm"
    },
    "IfcTextLiteral": {
        "attributes": {
            "Literal": "The text literal to be presented.",
            "Path": "The writing direction of the text literal.",
            "Placement": "An _IfcAxis2Placement_ that determines the placement and orientation of the presented string. > When used with a text style based on IfcTextStyleWithBoxCharacteristics then the y-axis is taken as the reference direction for the box rotation angle and the box slant angle."
        },
        "description": "Definition from IAI: The text literal is a geometric representation item which describes a text string using a string literal and additional position, and path information.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifctextliteral.htm"
    },
    "IfcTextLiteralWithExtent": {
        "attributes": {
            "BoxAlignment": "The alignment of the text literal relative to its position.",
            "Extent": "The extent in the x and y direction of the text literal."
        },
        "description": "Definition from IAI: The text literal with extent is a text literal with the additional explicit information of the planar extent (or surrounding text box). An alignment attribute defines, how the text box is aligned to the placement and how it may expand.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifctextliteralwithextent.htm"
    },
    "IfcTextStyle": {
        "attributes": {
            "TextCharacterAppearance": "A character style to be used for presented text.",
            "TextFontStyle": "The style applied to the text font for its visual appearance.   It defines the font family, font style, weight and size.",
            "TextStyle": "The style applied to the text block for its visual appearance.   It defines the text block characteristics, either for vector based or monospace text fonts (see select item _IfcTextStyleWithBoxCharacteristics_), or for true type text fonts (see select item _IfcTextStyleTextModel_."
        },
        "description": "Definition from ISO/CD 10303-46:1992: The text style is a presentation style for annotation text..",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextstyle.htm"
    },
    "IfcTextStyleFontModel": {
        "attributes": {
            "FontFamily": "The value is a prioritized list of font family names and/or generic family names. The first list entry has the highest priority, if this font fails, the next list item shall be used. The last list item should (if possible) be a generic family.",
            "FontSize": "The font size provides the size or height of the text font.    > NOTE  The following values are allowed, <IfcLengthMeasure, with positive values, the length unit is globally defined at IfcUnitAssignment.",
            "FontStyle": "The font style property selects between normal (sometimes referred to as \"roman\" or \"upright\"), italic and oblique faces within a font family.",
            "FontVariant": "The font variant property selects between normal and small-caps.    > NOTE  It has been introduced for later compliance to full CSS1 support.",
            "FontWeight": "The font weight property selects the weight of the font.    > NOTE  Values other then 'normal' and 'bold' have been introduced for later compliance to full CSS1 support."
        },
        "description": "Definition from CSS1 (W3C Recommendation): Setting font properties will be among the most common uses of style sheets. Unfortunately, there exists no well-defined and universally accepted taxonomy for classifying fonts, and terms that apply to one font family may not be appropriate for others. E.g. 'italic' is commonly used to label slanted text, but slanted text may also be labeled as being Oblique, Slanted, Incline, Cursive or Kursiv. Therefore it is not a simple problem to map typical font selection properties to a specific font.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationresource/lexical/ifctextstylefontmodel.htm"
    },
    "IfcTextStyleForDefinedFont": {
        "attributes": {
            "BackgroundColour": "This property sets the background color of an element.",
            "Colour": "This property describes the text color of an element (often referred to as the foreground color)."
        },
        "description": "Definition from ISO/CD 10303-46:1992: A text style for defined font is a character glyph style for pre-defined or externally defined text fonts.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextstylefordefinedfont.htm"
    },
    "IfcTextStyleTextModel": {
        "attributes": {
            "LetterSpacing": "The length unit indicates an addition to the default space between characters. Values can be negative, but there may be implementation-specific limits. The user agent is free to select the exact spacing algorithm. The letter spacing may also be influenced by justification (which is a value of the 'align' property).    > NOTE  The following values are allowed, IfcDescriptiveMeasure with value='normal', or IfcLengthMeasure, the length unit is globally defined at IfcUnitAssignment.",
            "LineHeight": "The property sets the distance between two adjacent lines' baselines.   When a ratio value is specified, the line height is given by the font size of the current element multiplied with the numerical value. A value of 'normal' sets the line height to a reasonable value for the element's font. It is suggested that user agents set the 'normal' value to be a ratio number in the range of 1.0 to 1.2.    > NOTE  The following values are allowed: IfcDescriptiveMeasure with value='normal', or  IfcLengthMeasure, with non-negative values, the length unit is globally defined at IfcUnitAssignment, or IfcRatioMeasure.",
            "TextAlign": "This property describes how text is aligned horizontally within the element. The actual justification algorithm used is dependent on the rendering algorithm.",
            "TextDecoration": "This property describes decorations that are added to the text of an element.",
            "TextIndent": "The property specifies the indentation that appears before the first formatted line.    > NOTE  It has been introduced for later compliance to full CSS1 support.",
            "TextTransform": "This property describes how text characters may transform to upper case, lower case, or capitalized case, independent of the character case used in the text literal.    > NOTE  It has been introduced for later compliance to full CSS1 support.",
            "WordSpacing": "The length unit indicates an addition to the default space between words. Values can be negative, but there may be implementation-specific limits. The user agent is free to select the exact spacing algorithm. The word spacing may also be influenced by justification (which is a value of the 'text-align' property).    > NOTE  It has been introduced for later compliance to full CSS1 support."
        },
        "description": "Definition from CSS1 (W3C Recommendation): The properties defined in the text model affect the visual presentation of characters, spaces, words, and paragraphs.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextstyletextmodel.htm"
    },
    "IfcTextStyleWithBoxCharacteristics": {
        "attributes": {
            "BoxHeight": "It is the height scaling factor in the definition of a character glyph.",
            "BoxRotateAngle": "It indicated that the box of a character glyph shall be presented at an angle to the base line of a text string within which the glyph occurs, the angle being that between the base line of the glyph and an axis perpendicular to the baseline of the text string.",
            "BoxSlantAngle": "It indicated that the box of a character glyph shall be represented as a parallelogram, with the angle being between the character up line and an axis perpendicular to the character base line.",
            "BoxWidth": "It is the width scaling factor in the definition of a character glyph.",
            "CharacterSpacing": "The distance between the character boxes of adjacent characters."
        },
        "description": "Definition from IAI: The text style with box characteristics allows the presentation of annotated text by specifying the characteristics of the character boxes of the text and the spacing between the character boxes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctextstylewithboxcharacteristics.htm"
    },
    "IfcTextureCoordinate": {
        "attributes": {
            "AnnotatedSurface": ""
        },
        "description": "Definition from IAI: The IfcTextureCoordinate a an abstract supertype of the different kinds to apply texture coordinates to geometries. For vertex based geometries an explicit assignment of 2D texture vertices to the 3D geometry vertices is supported, in addition there can be a procedural description of texture coordinates. For parametrically described base geometry types a default mapping procedure is given.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifctexturecoordinate.htm"
    },
    "IfcTextureCoordinateGenerator": {
        "attributes": {
            "Mode": "The mode describes the algorithm used to compute texture coordinates.",
            "Parameter": "The parameter used by the function as specified by Mode."
        },
        "description": "Definition from IAI: The IfcTextureCoordinateGenerator describes a procedurally defined mapping function with input parameter to map 2D texture coordinates to 3D geometry vertices. The allowable Mode values and input Parameter need to be agreed upon in implementer agreements.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifctexturecoordinategenerator.htm"
    },
    "IfcTextureMap": {
        "attributes": {
            "TextureMaps": "Reference to a list of texture vertex assignment to coordinates within a vertex based geometry."
        },
        "description": "Definition from IAI: An IfcTextureMap provides the mapping of the 2-dimensional texture coordinates to the surface onto which it is mapped. It is used for mapping the texture to vertex based geometry models, such as",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifctexturemap.htm"
    },
    "IfcTextureVertex": {
        "attributes": {
            "Coordinates": "The first coordinate[1] is the S, the second coordinate[2] is the T parameter value."
        },
        "description": "Definition from IAI: An IfcTextureVertex is a list of 2 (S, T) texture coordinates.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifctexturevertex.htm"
    },
    "IfcThermalMaterialProperties": {
        "attributes": {
            "BoilingPoint": "The boiling point of the material (fluid). Usually measured in Kelvin.",
            "FreezingPoint": "The freezing point of the material (fluid). Usually measured in Kelvin.",
            "SpecificHeatCapacity": "Defines the specific heat of the material: heat energy absorbed per temperature unit. Usually measured in [J/kg K].",
            "ThermalConductivity": "The rate at which thermal energy is transmitted through the material.Usually in [W/m K]."
        },
        "description": "A container class with material thermal properties defined in IFC specification.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcthermalmaterialproperties.htm"
    },
    "IfcTimeSeries": {
        "attributes": {
            "DataOrigin": "The orgin of a time series data.",
            "Description": "A text description of the data that the series represents.",
            "DocumentedBy": "",
            "EndTime": "The end time of a time series.",
            "Name": "An unique name for the time series.",
            "StartTime": "The start time of a time series.",
            "TimeSeriesDataType": "The time series data type.",
            "Unit": "The unit to be assigned to all values within the time series. Note that mixing units is not allowed. If the value is not given, the global unit for the type of _IfcValue_, as defined at _IfcProject.UnitsInContext_ is used.",
            "UserDefinedDataOrigin": "Value of the data origin if DataOrigin attribute is USERDEFINED."
        },
        "description": "A time series is a set of a time-stamped data entries. It allows a natural association of data collected over intervals of time. Time series can be regular or irregular. In regular time series data arrive predictably at predefined intervals. In irregular time series some or all time stamps do not follow a repetitive pattern and unpredictable bursts of data may arrive at unspecified points in time.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifctimeseries.htm"
    },
    "IfcTimeSeriesReferenceRelationship": {
        "attributes": {
            "ReferencedTimeSeries": "",
            "TimeSeriesReferences": ""
        },
        "description": "Relationship assigning documentation references to time series.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifctimeseriesreferencerelationship.htm"
    },
    "IfcTimeSeriesSchedule": {
        "attributes": {
            "ApplicableDates": "Defines an ordered list of the dates for which the time-series data are applicable. For example, the definition of all public holiday dates for a given year allows the formulation of a \"holiday\" occupancy schedule from overall occupancy data. Local time can be used if the dates are not bound to a particular year.",
            "TimeSeries": "The time series is used to represent the values at discrete points in time that define the schedule. For example, a 24-hour occupancy schedule would be a regular time series with a start time at midnight, end time at (the following) midnight, and with 24 values indicating the occupancy load for each hour of the 24-hour period.",
            "TimeSeriesScheduleType": "Defines the type of schedule, such as daily, weekly, monthly or annually."
        },
        "description": "The IfcTimeSeriesSchedule defines a time-series that is applicable to to one or more calendar dates. It typically contains a periodically repetitive time series used to define the schedule, facilitating the capture of hours of operation, occupancy loads, etc.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifccontrolextension/lexical/ifctimeseriesschedule.htm"
    },
    "IfcTimeSeriesValue": {
        "attributes": {
            "ListValues": "A list of time-series values. At least one value is required."
        },
        "description": "A time series value is a list of values that comprise the time series. At least one value must be supplied. Applications are expected to normalize values by applying the following three rules:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctimeseriesresource/lexical/ifctimeseriesvalue.htm"
    },
    "IfcTopologicalRepresentationItem": {
        "description": "Definition from ISO/CD 10303-42:1992: The topological representation item is the supertype for all the topological representation items in the geometry resource.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifctopologicalrepresentationitem.htm"
    },
    "IfcTopologyRepresentation": {
        "description": "Definition from IAI: The IfcTopologyRepresentation represents the concept of a particular topological representation of a product or a product component within a representation context. This representation context does not need to be (but may be) a geometric representation context. Several representation types for shape representation are included as predefined types:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcrepresentationresource/lexical/ifctopologyrepresentation.htm"
    },
    "IfcTransformerType": {
        "description": "An IfcTransformerType defines a particular type of transformer that is an inductive stationary device that transfers electrical energy from one circuit to another.",
        "predefined_types": {
            "CURRENT": "A transformer that changes the current between circuits.",
            "FREQUENCY": "A transformer that changes the frequency between circuits.",
            "NOTDEFINED": "Undefined type.",
            "USERDEFINED": "User-defined type.",
            "VOLTAGE": "A transformer that changes the voltage between circuits."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcelectricaldomain/lexical/ifctransformertype.htm"
    },
    "IfcTransportElement": {
        "attributes": {
            "CapacityByNumber": "Capacity of the transportation element measured in numbers of person.",
            "CapacityByWeight": "Capacity of the transport element measured by weight.",
            "OperationType": "Predefined type for transport element."
        },
        "description": "Generalization of all transport related objects that move people, animals or goods within a building or building complex. The IfcTransportElement defines the occurrence of a covering type, that (if given) is expressed by the IfcTransportElementType.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifctransportelement.htm"
    },
    "IfcTransportElementType": {
        "description": "The element type (IfcTransportElementType) defines a list of commonly shared property set definitions of an element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "ELEVATOR": "Elevator or lift being a transport device to move people of good vertically.",
            "ESCALATOR": "Escalator being a transport device to move people. It consists of individual linked steps that move up and down on tracks while keeping the threads horizontal.",
            "MOVINGWALKWAY": "Moving walkway being a transport device to move people horizontally or on an incline. It is a slow conveyor belt that transports people.",
            "NOTDEFINED": "",
            "USERDEFINED": ""
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifctransportelementtype.htm"
    },
    "IfcTrapeziumProfileDef": {
        "attributes": {
            "BottomXDim": "The extent of the bottom line measured along the implicit x-axis.",
            "TopXDim": "The extent of the top line measured along the implicit x-axis.",
            "TopXOffset": "Offset from the beginning of the top line to the bottom line, measured along the implicit x-axis.",
            "YDim": "The extent of the distance between the parallel bottom and top lines measured along the implicit y-axis."
        },
        "description": "Definition from IAI: The IfcTrapeziumProfileDef defines a trapezium as the profile definition used by the swept surface geometry or the swept area solid. It is given by its Top X and Bottom X extent and its Y extent as well as by the offset of the Top X extend, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, i.e. in the center of the bounding box.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifctrapeziumprofiledef.htm"
    },
    "IfcTrimmedCurve": {
        "attributes": {
            "BasisCurve": "The curve to be trimmed. For curves with multiple representations any parameter values given as Trim1 or Trim2 refer to the master representation of the BasisCurve only.",
            "MasterRepresentation": "Where both parameter and point are present at either end of the curve this indicates the preferred form.",
            "SenseAgreement": "Flag to indicate whether the direction of the trimmed curve agrees with or is opposed to the direction of the basis curve.",
            "Trim1": "The first trimming point which may be specified as a Cartesian point, as a real parameter or both.",
            "Trim2": "The second trimming point which may be specified as a Cartesian point, as a real parameter or both."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A trimmed curve is a bounded curve which is created by taking a selected portion, between two identified points, of the associated basis curve. The basis curve itself is unaltered and more than one trimmed curve may reference the same basis curve. Trimming points for the curve may be identified by:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifctrimmedcurve.htm"
    },
    "IfcTubeBundleType": {
        "description": "The element type IfcTubeBundleType defines a list of commonly shared property set definitions of a tube buncle and an optional set of product representations. It is used to define a tube bundle specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "FINNED": "Finned tube bundle type.",
            "NOTDEFINED": "Undefined tube bundle type.",
            "USERDEFINED": "User-defined tube bundle type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifctubebundletype.htm"
    },
    "IfcTwoDirectionRepeatFactor": {
        "attributes": {
            "SecondRepeatFactor": "A vector which specifies the relative positioning of tiles in the second direction."
        },
        "description": "Definition from ISO/CD 10303-46:1992: A two direction repeat factor combines two vectors which are used in the fill area style tiles entity for determining the shape and relative location of tiles. Given the initial position of any tile, the two direction repeat factor determines eight new positions according to the equation:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationappearanceresource/lexical/ifctwodirectionrepeatfactor.htm"
    },
    "IfcTypeObject": {
        "attributes": {
            "ApplicableOccurrence": "The attribute optionally defines the data type of the occurrence object, to which the assigned type object can relate. If not present, no instruction is given to which occurrence object the type object is applicable.",
            "HasPropertySets": "Set ~~list~~ of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type.",
            "ObjectTypeOf": "Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type."
        },
        "description": "The object type (IfcTypeObject) defines the specific information about a type. It refers to the specific level of the well recognized generic - specific - occurrence modeling paradigm.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifctypeobject.htm"
    },
    "IfcTypeProduct": {
        "attributes": {
            "RepresentationMaps": "List of unique representation maps. Each representation map describes a block definition of the shape of the product style. By providing more than one representation map, a multi-view block definition can be given.",
            "Tag": "The tag (or label) identifier at the particular type of a product, e.g. the article number (like the EAN). It is the identifier at the specific level."
        },
        "description": "The product type (IfcTypeProduct) defines a list of property set definitions of a product and an optional set of product representations. It is used to define a product specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifckernel/lexical/ifctypeproduct.htm"
    },
    "IfcUShapeProfileDef": {
        "attributes": {
            "CentreOfGravityInX": "Location of centre of gravity along the x axis measured from the center of the bounding box.",
            "Depth": "Web lengths, see illustration above (= h).",
            "EdgeRadius": "Edge radius according the above illustration (= r2). If it is not given, zero is assumed.",
            "FilletRadius": "Fillet radius according the above illustration (= r1). If it is not given, zero is assumed.",
            "FlangeSlope": "Slope of flange of the profile. If it is not given, zero is assumed.",
            "FlangeThickness": "Constant wall thickness of flange (= tg).",
            "FlangeWidth": "Flange lengths, see illustration above (= b).",
            "WebThickness": "Constant wall thickness of web (= ts)."
        },
        "description": "The IfcUShapeProfileDef defines a section profile that provides the defining parameters of a U-shape (channel) section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the\\^profiles centre of the ~~gravity~~ bounding box.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifcushapeprofiledef.htm"
    },
    "IfcUnitAssignment": {
        "attributes": {
            "Units": "Units to be included within a unit assignment."
        },
        "description": "A set of units which may be assigned. Within an IfcUnitAssigment each unit definition shall be unique. I.e. there shall be no redundant unit definitions for the same unit type, like length unit, area unit etc. For currencies, there shall be only a single IfcMonetaryUnit within an IfcUnitAssignment.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmeasureresource/lexical/ifcunitassignment.htm"
    },
    "IfcUnitaryEquipmentType": {
        "description": "The element type IfcUnitaryEquipmentType defines a list of commonly shared property set definitions of a unitary equipment element and an optional set of product representations. It is used to define a unitary equipment element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "AIRCONDITIONINGUNIT": "A unitary packaged air-conditioning unit typically used in residential or light commercial applications.",
            "AIRHANDLER": "A unitary air handling unit typically containing a fan, economizer, and coils.",
            "NOTDEFINED": "Undefined unitary equipment type.",
            "ROOFTOPUNIT": "A packaged assembly that is either field-erected or manufactured atop the roof of a large residential or commercial building and acts as a unitary component.",
            "SPLITSYSTEM": "A system which separates the compressor from the evaporator, but acts as a unitary component typically within residential or light commercial applications.",
            "USERDEFINED": "User-defined unitary equipment type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcunitaryequipmenttype.htm"
    },
    "IfcValveType": {
        "description": "The element type IfcValveType defines a list of commonly shared property set definitions of a valve and an optional set of product representations. It is used to define a valve specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "AIRRELEASE": "Valve used to release air from a pipe or fitting.",
            "ANTIVACUUM": "Valve that opens to admit air if the pressure falls below atmospheric pressure.",
            "CHANGEOVER": "Valve that enables flow to be switched between pipelines (3 or 4 port).",
            "CHECK": "Valve that permits water to flow in one direction only and is enclosed when there is no flow (2 port).",
            "COMMISSIONING": "Valve used to facilitate commissioning of a system (2 port).",
            "DIVERTING": "Valve that enables flow to be diverted from one branch of a pipeline to another (3 port).",
            "DOUBLECHECK": "An assembly that incorporates two valves used to prevent backflow.",
            "DOUBLEREGULATING": "Valve used to facilitate regulation of fluid flow in a system.",
            "DRAWOFFCOCK": "A valve used to remove fluid from a piping system.",
            "FAUCET": "Faucet valve typically used as a flow discharge.",
            "FLUSHING": "Valve that flushes a predetermined quantity of water to cleanse a toilet, urinal, etc.",
            "GASCOCK": "Valve that is used for controlling the flow of gas.",
            "GASTAP": "Gas tap typically used for venting or discharging gas from a system.",
            "ISOLATING": "Valve that closes off flow in a pipeline.",
            "MIXING": "Valve that enables flow from two branches of a pipeline to be mixed together (3 port).",
            "NOTDEFINED": "Undefined valve type.",
            "PRESSUREREDUCING": "Valve that reduces the pressure of a fluid immediately downstream of its position in a pipeline to a preselected value or by a predetermined ratio.",
            "PRESSURERELIEF": "Spring or weight loaded valve that automatically discharges to a safe place fluid that has built up to excessive pressure in pipes or fittings.",
            "REGULATING": "Valve used to facilitate regulation of fluid flow in a system.",
            "SAFETYCUTOFF": "Valve that closes under the action of a safety mechanism such as a drop weight, solenoid etc.",
            "STEAMTRAP": "Valve that restricts flow of steam while allowing condensate to pass through.",
            "STOPCOCK": "An isolating valve used on a domestic water service.",
            "USERDEFINED": "User-defined valve type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcvalvetype.htm"
    },
    "IfcVector": {
        "attributes": {
            "Dim": "The space dimensionality of this class, it is derived from Orientation Orientation.Dim",
            "Magnitude": "The magnitude of the vector. All vectors of Magnitude 0.0 are regarded as equal in value regardless of the orientation attribute.",
            "Orientation": "The direction of the vector."
        },
        "description": "Definition from ISO/CD 10303-42:1992: The vector is defined in terms of the direction and magnitude of the vector. The value of the magnitude attribute defines the magnitude of the vector.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometryresource/lexical/ifcvector.htm"
    },
    "IfcVertex": {
        "description": "Definition from ISO/CD 10303-42:1992: A vertex is the topological construct corresponding to a point. It has dimensionality 0 and extent 0. The domain of a vertex, if present, is a point in m dimensional real space R^M^; this is represented by the vertex point subtype.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcvertex.htm"
    },
    "IfcVertexBasedTextureMap": {
        "attributes": {
            "TexturePoints": "Reference to a list of polyloop's defining a face bound of a face within a vertex based geometry.",
            "TextureVertices": "List of texture vertex coordinates, each texture vertex refers to the Cartesian point within the polyloop (corresponding lists). The first coordinate[1] is the S, the second coordinate[2] is the T parameter value."
        },
        "description": "Definition from IAI: An IfcVertexBasedTextureMap provides the mapping of the 2-dimensional texture coordinates (S, T) to the vertices of a single surface onto which it is mapped. For each vertex coordinates, provided by IfcCartesianPoin, a set of 2 (S, T) texture coordinates are given.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcpresentationdefinitionresource/lexical/ifcvertexbasedtexturemap.htm"
    },
    "IfcVertexLoop": {
        "attributes": {
            "LoopVertex": "The vertex which defines the entire loop."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A vertex_loop is a loop of zero genus consisting of a single vertex. A vertex can exist independently of a vertex loop. The topological data shall satisfy the following constraint:",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcvertexloop.htm"
    },
    "IfcVertexPoint": {
        "attributes": {
            "VertexGeometry": "The geometric point, which defines the position in geometric space of the vertex."
        },
        "description": "Definition from ISO/CD 10303-42:1992: A vertex point is a vertex which has its geometry defined as a point.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifctopologyresource/lexical/ifcvertexpoint.htm"
    },
    "IfcVibrationIsolatorType": {
        "description": "The element type IfcVibrationIsolatorType defines a list of commonly shared property set definitions of a vibration isolator and an optional set of product representations. It is used to define a vibration isolator specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "COMPRESSION": "Compression type vibration isolator.",
            "NOTDEFINED": "Undefined vibration isolator type.",
            "SPRING": "Spring type vibration isolator.",
            "USERDEFINED": "User-defined vibration isolator type."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifchvacdomain/lexical/ifcvibrationisolatortype.htm"
    },
    "IfcVirtualElement": {
        "description": "A special element used to provide imaginary boundaries, such as between two adjacent, but not separated, spaces. Virtual elements are usually not displayed and does not have quantities and other measures. Therefore IfcVirtualElement does not have material information and quantities attached.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifcvirtualelement.htm"
    },
    "IfcVirtualGridIntersection": {
        "attributes": {
            "IntersectingAxes": "Two grid axes which intersects at exactly one intersection (see also informal proposition at IfcGrid). If attribute OffsetDistances is omitted, the intersection defines the placement or ref direction of a grid placement directly. If OffsetDistances are given, the intersection is defined by the offset curves to the grid axes.",
            "OffsetDistances": "Offset distances to the grid axes. If given, it defines virtual offset curves to the grid axes. The intersection of the offset curves specify the virtual grid intersection."
        },
        "description": "The IfcVirtualGridIntersection defines the derived location of the intersection between two grid axes. Offset values may be given to set an offset distance to the grid axis for the calculation of the virtual grid intersection.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcgeometricconstraintresource/lexical/ifcvirtualgridintersection.htm"
    },
    "IfcWall": {
        "description": "Definition from ISO 6707-1:1989: Vertical construction usually in masonry or in concrete which bounds or subdivides a construction works and fulfills a load bearing or retaining function.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwall.htm"
    },
    "IfcWallStandardCase": {
        "description": "The standard wall (IfcWallStandardCase) defines a wall with certain constraints for the provision of parameters and with certain constraints for the geometric representation. The IfcWallStandardCase handles all cases of walls, that are extruded vertically ",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwallstandardcase.htm"
    },
    "IfcWallType": {
        "description": "The element type (IfcWallType) defines a list of commonly shared property set definitions of a wall and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).",
        "predefined_types": {
            "ELEMENTEDWALL": "A stud wall framed with studs and faced with sheetings, sidings, wallboard, or plasterwork.",
            "NOTDEFINED": "Undefined wall element.",
            "PLUMBINGWALL": "A pier, or enclosure, or encasement, normally used to enclose plumbing in sanitary rooms. Such walls often do not extent to the ceiling.",
            "POLYGONAL": "A polygonal wall, extruded vertically, where the wall thickness varies along the wall path.\n{ .deprecated}\n> IFC4 DEPRECATION&nbsp; The enumerator POLYGONAL is deprecated and shall no longer be used.",
            "SHEAR": "A wall designed to withstand shear loads. Such shear walls are often designed having a non-rectangular cross section along the wall path. Also called retaining walls or supporting walls they are used to protect against soil layers behind.",
            "STANDARD": "A standard wall, extruded vertically with a constant thickness along the wall path.",
            "USERDEFINED": "User-defined wall element."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwalltype.htm"
    },
    "IfcWasteTerminalType": {
        "description": "The IfcWasteTerminalType defines a particular type of sanitary flow that has the purpose of collecting or intercepting waste from one or more sanitary terminals or other fluid waste generating equipment and discharging it into a single waste/drainage system.",
        "predefined_types": {
            "FLOORTRAP": "Pipe fitting, set into the floor, that retains liquid to prevent the passage of foul air",
            "FLOORWASTE": "Pipe fitting, set into the floor, that collects waste water and discharges it to a separate trap.",
            "GREASEINTERCEPTOR": "",
            "GULLYSUMP": "Pipe fitting or assembly of fittings to receive surface water or waste water, fitted with a grating or sealed cover.",
            "GULLYTRAP": "Pipe fitting or assembly of fittings that receives surface water or waste water; fitted with a grating or sealed cover that discharges water through a trap.",
            "NOTDEFINED": "Undefined type.",
            "OILINTERCEPTOR": "",
            "PETROLINTERCEPTOR": "",
            "ROOFDRAIN": "Pipe fitting, set into the roof, that collects rainwater for discharge into the rainwater system.",
            "USERDEFINED": "User-defined type.",
            "WASTEDISPOSALUNIT": "Electrically operated device that reduces kitchen or other waste into fragments small enough to be flushed into a drainage system.",
            "WASTETRAP": "Pipe fitting, set adjacent to a sanitary terminal, that retains liquid to prevent the passage of foul air."
        },
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcplumbingfireprotectiondomain/lexical/ifcwasteterminaltype.htm"
    },
    "IfcWaterProperties": {
        "attributes": {
            "AcidityConcentration": "Maximum CaCO~3~ equivalent that would neutralize the acid.",
            "AlkalinityConcentration": "Maximum alkalinity concentration (maximum sum of concentrations of each of the negative ions substances measured as CaCO~3~).",
            "DissolvedSolidsContent": "Fraction of the dissolved solids to the total amount of water. This is measured in weight of dissolved solids per weight of water and is therefore unitless.",
            "Hardness": "Water hardness as positive, multivalent ion concentration in the water (usually concentrations of calcium and magnesium ions in terms of calcium carbonate).",
            "ImpuritiesContent": "Fraction of impurities such as dust to the total amount of water. This is measured in weight of impurities per weight of water and is therefore unitless.",
            "IsPotable": "If TRUE, then the water is considered potable.",
            "PHLevel": "Maximum water ph in a range from 0-14."
        },
        "description": "Common definition to capture the properties of water typically used within the context of building services and flow distribution systems.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcmaterialpropertyresource/lexical/ifcwaterproperties.htm"
    },
    "IfcWindow": {
        "attributes": {
            "OverallHeight": "Overall measure of the height, it reflects the Z Dimension of a bounding box, enclosing the ~~body of the~~ window opening. If omitted, the _OverallHeight_ should be taken from the geometric representation of the _IfcOpening_ in which the window is inserted.     >  NOTE  The body of the window might be taller then the window opening (e.g. in cases where the window lining includes a casing). In these cases the OverallHeight shall still be given as the window opening height, and not as the total height of the window lining.",
            "OverallWidth": "Overall measure of the width, it reflects the X Dimension of a bounding box, enclosing the ~~body of the~~ window opening. If omitted, the _OverallWidth_ should be taken from the geometric representation of the _IfcOpening_ in which the window is inserted.     >  NOTE  The body of the window might be wider then the window opening (e.g. in cases where the window lining includes a casing). In these cases the OverallWidth shall still be given as the window opening width, and not as the total width of the window lining."
        },
        "description": "Definition form ISO 6707-1:1989: Construction for closing a vertical or near vertical opening in a wall or pitched roof that will admit light and may admit fresh air.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindow.htm"
    },
    "IfcWindowLiningProperties": {
        "attributes": {
            "FirstMullionOffset": "Offset of the mullion centerline, measured along the x-axis of the window placement co-ordinate system. An offset value = 0.5 indicates that the mullion is positioned in the middle of the window.",
            "FirstTransomOffset": "Offset of the transom centerline, measured along the z-axis of the window placement co-ordinate system. An offset value = 0.5 indicates that the transom is positioned in the middle of the window.",
            "LiningDepth": "Depth of the window lining (dimension measured perpendicular to window elevation plane).",
            "LiningThickness": "Thickness of the window lining (measured parallel to the window elevation plane).",
            "MullionThickness": "Thickness of the mullion (vertical separator of window panels within a window), measured parallel to the window elevation plane. The mullion is part of the lining and the mullion depth is assumed to be identical to the lining depth.",
            "SecondMullionOffset": "Offset of the mullion centerline for the second mullion, measured along the x-axis of the window placement co-ordinate system. An offset value = 0.666 indicates that the second mullion is positioned at two/third of the window.",
            "SecondTransomOffset": "Offset of the transom centerline for the second transom, measured along the x-axis of the window placement co-ordinate system. An offset value = 0.666 indicates that the second transom is positioned at two/third of the window.",
            "ShapeAspectStyle": "Optional link to a shape aspect definition, which points to the part of the geometric representation of the window style, which is used to represent the lining.",
            "TransomThickness": "Thickness of the transom (horizontal separator of window panels within a window), measured parallel to the window elevation plane. The transom is part of the lining and the transom depth is assumed to be identical to the lining depth."
        },
        "description": "The window lining is the frame which enables the window to be fixed in position. The window lining is used to hold the window panels or other casements. The parameter of the window lining (IfcWindowLiningProperties) define the geometrically relevant parameter of the lining.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindowliningproperties.htm"
    },
    "IfcWindowPanelProperties": {
        "attributes": {
            "FrameDepth": "Depth of panel frame, measured from front face to back face horizontally (i.e. perpendicular to the window (elevation) plane.",
            "FrameThickness": "Width of panel frame, measured from inside of panel (at glazing) to outside of panel (at lining), i.e. parallel to the window (elevation) plane.",
            "OperationType": "Types of window panel operations. Also used to assign standard symbolic presentations according to national building standards.",
            "PanelPosition": "Position of this panel within the overall window style.",
            "ShapeAspectStyle": "Optional link to a shape aspect definition, which points to the part of the geometric representation of the window style, which is used to represent the panel."
        },
        "description": "A description of the window panel. A window panel is a casement, i.e. a component, fixed or opening, consisting essentially of a frame and the infilling. The infilling of a window panel is normally glazing. The way of operation is defined in the operation type.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindowpanelproperties.htm"
    },
    "IfcWindowStyle": {
        "attributes": {
            "ConstructionType": "Type defining the basic construction and material type of the window.",
            "OperationType": "Type defining the general layout and operation of the window style.",
            "ParameterTakesPrecedence": "The Boolean value reflects, whether the parameter given in the attached lining and panel properties exactly define the geometry (TRUE), or whether the attached style shape take precedence (FALSE). In the last case the parameter have only informative value.",
            "Sizeable": "The Boolean indicates, whether the attached ShapeStyle can be sized (using scale factor of transformation), or not (FALSE). If not, the ShapeStyle should be inserted by the IfcWindow (using IfcMappedItem) with the scale factor = 1."
        },
        "description": "The window style defines a particular style of windows, which may be included into the spatial context of the building model through an (or multiple) instances of IfcWindow. A window style defines the overall parameter of the window style and refers to the particular parameter of the lining and one (or several) panels through the IfcWindowLiningProperties and the IfcWindowPanelProperties.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcsharedbldgelements/lexical/ifcwindowstyle.htm"
    },
    "IfcWorkControl": {
        "attributes": {
            "CreationDate": "The date that the plan is created.",
            "Creators": "The authors of the work plan.",
            "Duration": "The total duration of the entire work schedule.",
            "FinishTime": "The finish time of the schedule.",
            "Identifier": "Identifier of the work plan, given by user.",
            "Purpose": "A description of the purpose of the work schedule.",
            "StartTime": "The start time of the schedule.",
            "TotalFloat": "The total time float of the entire work schedule.",
            "UserDefinedControlType": "A user defined work control type.",
            "WorkControlType": "Predefined work control types from which that required may be set."
        },
        "description": "An IfcWorkControl is an abstract supertype which captures information that is common to both IfcWorkPlan and IfcWorkSchedule",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcworkcontrol.htm"
    },
    "IfcWorkPlan": {
        "description": "An IfcWorkPlan represents work plans in a construction or a facilities management project.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcworkplan.htm"
    },
    "IfcWorkSchedule": {
        "description": "An IfcWorkSchedule represents a task schedule in a work plan, which in turn can contain a set of schedules for different purposes.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprocessextension/lexical/ifcworkschedule.htm"
    },
    "IfcZShapeProfileDef": {
        "attributes": {
            "Depth": "Web length, see illustration above (= h).",
            "EdgeRadius": "Edge radius according the above illustration (= r2). If it is not given, zero is assumed.",
            "FilletRadius": "Fillet radius according the above illustration (= r1). If it is not given, zero is assumed.",
            "FlangeThickness": "Constant wall thickness of flange, see illustration above (= tg).",
            "FlangeWidth": "Flange length, see illustration above (= b).",
            "WebThickness": "Constant wall thickness of web, see illustration above (= ts)."
        },
        "description": "Definition from IAI: The IfcZShapeProfileDef defines a section profile that provides the defining parameters of a Z-shape section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the gravity bounding box.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcprofileresource/lexical/ifczshapeprofiledef.htm"
    },
    "IfcZone": {
        "description": "A zone (IfcZone) is an aggregation of spaces, partial spaces or other zones. Zone structures may not be hierarchical (in contrary to the spatial structure of a project - see IfcSpatialStructureElement), i.e. one individual IfcSpace may be associated with zero, one, or several IfcZone's. IfcSpace's are aggregated into an IfcZone by using the objectified relationship IfcRelAssignsToGroup as specified at the supertype IfcGroup.",
        "spec_url": "https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/TC1/HTML/ifcproductextension/lexical/ifczone.htm"
    }
}