32;Identification;Identification of the organization.
33;Name;The word, or group of words, by which the organization is referred to.
34;Description;Text that relates the nature of the organization.
35;Roles;Roles played by the organization.
36;Addresses;"<EPM-HTML>
Postal and telecom addresses of an organization.
<blockquote><small>NOTE: There may be several addresses related to an organization.
</small></blockquote>
</EPM-HTML>"
37;IsRelatedBy;The inverse relationship for relationship RelatedOrganizations of IfcOrganizationRelationship.
38;Relates;The inverse relationship for relationship RelatingOrganization of IfcOrganizationRelationship.
39;Engages;Inverse relationship to IfcPersonAndOrganization relationships in which IfcOrganization is engaged.
41;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."
42;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."
43;Description;A textual description relating the nature of the role played by an actor.
44;HasExternalReference;"<EPM-HTML>
Reference to external information, e.g. library, classification, or document information, which is associated with the actor role.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE New inverse attribute.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
73;Purpose;Identifies the logical location of the address.
74;Description;Text that relates the nature of the address.
75;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."
76;OfPerson;The inverse relationship to Person to whom address is associated.
77;OfOrganization;The inverse relationship to Organization to whom address is associated.
80;InternalLocation;An organization defined address for internal mail delivery.
81;AddressLines;"<EPM-HTML>
The postal address.
<blockquote><small>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.
</small></blockquote>
</EPM-HTML>
"
82;PostalBox;An address that is implied by an identifiable mail drop.
83;Town;The name of a town.
84;Region;"<EPM-HTML>
The name of a region.
<blockquote><small>NOTE: The counties of the United Kingdom and the states of North America are examples of regions.
</small></blockquote>
</EPM-HTML>
"
85;PostalCode;The code that is used by the country's postal service.
86;Country;The name of a country.
89;TelephoneNumbers;The list of telephone numbers at which telephone messages may be received.
90;FacsimileNumbers;The list of fax numbers at which fax messages may be received.
91;PagerNumber;The pager number at which paging messages may be received.
92;ElectronicMailAddresses;The list of Email addresses at which Email messages may be received.
93;WWWHomePageURL;"<EPM-HTML>
The world wide web address at which the preliminary page of information for the person or organization can be located.
<blockquote><small>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.
</font></blockquote>
</EPM-HTML>"
94;MessagingIDs;IDs or addresses for any other means of telecommunication, for example instant messaging, voice-over-IP, or file transfer protocols. The communication protocol is indicated by the URI value with scheme designations such as irc:, sip:, or ftp:.
103;Identification;Identification of the person.
104;FamilyName;"<EPM-HTML>
The name by which the family identity of the person may be recognized.
<blockquote><small>NOTE: Depending on geographical location and culture, family name may appear either as the first or last component of a name.</small></blockquote>
</EPM-HTML>
"
105;GivenName;"<EPM-HTML>
The name by which a person is known within a family and by which he or she may be familiarly recognized.
<blockquote><small>NOTE: Depending on geographical location and culture, given name may appear either as the first or last component of a name.</small></blockquote>
</EPM-HTML>
"
106;MiddleNames;"<EPM-HTML>
Additional names given to a person that enable their identification apart from others who may have the same or similar family and given names.
<blockquote><small>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.
</small></blockquote>
</EPM-HTML>
"
107;PrefixTitles;The word, or group of words, which specify the person's social and/or professional standing and appear before his/her names.
108;SuffixTitles;The word, or group of words, which specify the person's social and/or professional standing and appear after his/her names.
109;Roles;Roles played by the person.
110;Addresses;"<EPM-HTML>
Postal and telecommunication addresses of a person.
<blockquote><small>NOTE - A person may have several addresses.
</small></blockquote>
</EPM-HTML>
"
111;EngagedIn;The inverse relationship to IfcPersonAndOrganization relationships in which IfcPerson is engaged.
114;ThePerson;The person who is related to the organization.
115;TheOrganization;The organization to which the person is related.
116;Roles;"<EPM-HTML>

Roles played by the person within the context of an organization.  These may differ from the roles in <i>ThePerson.Roles</i> which may be asserted without organizational context.

</EPM-HTML>
"
118;Name;The word or group of words by which the relationship is referred to.
119;Description;Text that relates the nature of the relationship.
120;RelatingOrganization;Organization which is the relating part of the relationship between organizations.
121;RelatedOrganizations;The other, possibly dependent, organizations which are the related parts of the relationship between organizations.
124;Identifier;A computer interpretable identifier by which the approval is known.
125;Name;A human readable name given to an approval.
126;Description;"A general textual description of a design, work task, plan, etc. that is being approved for. 
"
127;TimeOfApproval;"<EPM-HTML>
Date and time when the result of the approval process is produced.
<blockquote>
  <p>
    <span style=""font-size:smaller;color:red"">
IFC2x4 CHANGE&nbsp; Attribute data type changed to <i>IfcDateTime</i> using ISO 8601 representation, renamed from ApprovalDateTime and made OPTIONAL.
    </span>
  </p>
</blockquote>
</EPM-HTML>"
128;Status;The result or current status of the approval, e.g. Requested, Processed, Approved, Not Approved.
129;Level;Level of the approval e.g. Draft v.s. Completed design.
130;Qualifier;Textual description of special constraints or conditions for the approval.
131;RequestingApproval;"<EPM-HTML>
The actor that is acting in the role specified at <em>IfcOrganization</em> or individually at <em>IfcPerson</em> and requesting an approval.
<blockquote>
  <p>
    <span style=""font-size:smaller;color:red"">
IFC2x4 CHANGE&nbsp; New attribute for approval request replacing IfcApprovalActorRelationship (being deleted).
    </span>
  </p>
</blockquote>
</EPM-HTML>"
132;GivingApproval;"<EPM-HTML>
The actor that is acting in the role specified at <em>IfcOrganization</em> or individually at <em>IfcPerson</em> and giving an approval.
<blockquote>
  <p>
    <span style=""font-size:smaller;color:red"">
IFC2x4 CHANGE&nbsp; New attribute for approval provision replacing IfcApprovalActorRelationship (being deleted).
    </span>
  </p>
</blockquote>
</EPM-HTML>"
133;HasExternalReferences;"<EPM-HTML>
Reference to external references, e.g. library, classification, or document information, that are associated to the Approval.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE New inverse attribute.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
134;ApprovedObjects;Reference to the <i>IfcRelAssociatesApproval</i> instances associating this approval to objects (subtypes of <i>IfcRoot</i>
135;ApprovedResources;The set of relationships by which resource objects that are are approved by this approval are known.
136;IsRelatedWith;The set of relationships by which this approval is related to others.
137;Relates;The set of relationships by which other approvals are related to this one.
140;RelatingApproval;The approval that other approval is related to.
141;RelatedApprovals;"The approvals that are related to another (relating) approval.<blockquote><small><font color=""#FF0000"">IFC2x Edition 4 CHANGE The cardinality of this attribute has been changed to SET.</font></small></blockquote>"
143;RelatedResourceObjects;"<EPM-HTML>
Resource objects that are approved.
</EPM-HTML>"
144;RelatingApproval;The approval for the resource objects selected.
147;LifeCyclePhase;Describes the applicable building life-cycle phase. Typical values should be DESIGNDEVELOPMENT, SCHEMATICDEVELOPMENT, CONSTRUCTIONDOCUMENT, CONSTRUCTION, ASBUILT, COMMISSIONING, OPERATION, etc.
148;PredefinedType;"<EPM-HTML>
Predefined generic type for a performace history that is specified in an enumeration.
<blockquote> 
  <small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font>
  </small>
</blockquote>
</EPM-HTML>"
153;RelatingApproval;Reference to approval that is being applied using this relationship.
155;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.
156;RelatingConstraint;Reference to constraint that is being applied using this relationship.
158;ApplicableDates;"<EPM-HTML>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 (as a list of <i>IfcDate</i>) allows the formulation of a ""holiday"" occupancy schedule from overall occupancy data.

<blockquote> <font color=""#FF0000"" SIZE=""-1"">IFC2x2 Addendum 1 CHANGE: The attribute has been changed to be optional </font></blockquote>

<blockquote><small><font color=""#FF0000"">Note IFC2x Edition 4 CHANGE: New underlying type <i>IfcDate</i> using ISO 8601 representation.</font></small></blockquote>

</EPM-HTML>
"
159;TimeSeriesScheduleType;Defines the type of schedule, such as DAILY, WEEKLY, MONTHLY or ANNUALLY.
160;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.
163;PredefinedType;Subtype of pile.
175;PredefinedType;Subtype of footing.
186;PredefinedType;Indicates the kind of surface feature.
195;PredefinedType;Qualifies the feature regarding its shape and configuration relative to the voided element.
207;PredefinedType;"<EPM-HTML>

The generic type of the footing.

<blockquote><font color=""#0000ff"" size=""-1"">IFC 2x4 change:&nbsp; Attribute made optional.  Type information can be provided by <i>IfcRelDefinesByType</i> and <i>IfcFootingType</i>.</font></blockquote>

</EPM-HTML>"
211;PredefinedType;"<EPM-HTML>

The predefined generic type of the pile according to function.

<blockquote><font color=""#0000ff"" size=""-1"">IFC 2x4 change:&nbsp; Attribute made optional.  Type information can be provided by <i>IfcRelDefinesByType</i> and <i>IfcPileType</i>.</font></blockquote>

</EPM-HTML>"
212;ConstructionType;"<EPM-HTML>

General designator for how the pile is constructed.

<blockquote><font color=""#0000ff"" size=""-1"">IFC 2x4 change:&nbsp; Material profile association capability by means of <i>IfcRelAssociatesMaterial</i> has been added.  The attribute <i>ConstructionType</i> should not be used whenever its information can be provided by a material profile set, either associated with the <i>IfcPile</i> object or, if present, with a corresponding instance of <i>IfcPileType</i>.</font></blockquote>

</EPM-HTML>"
225;PredefinedType;Subtype of reinforcement element.
226;BendingShapeCode;"<EPM-HTML>
Shape code per a standard like ACI 315, ISO 3766, or a similar standard.  It is presumed that a single standard for defining the bar bending is used throughout the project and that this standard is referenced from the <i>IfcProject</i> object through the <i>IfcDocumentReference</i> mechanism.
</EPM-HTML>"
227;BendingParameters;Bending shape parameters.  Their meaning is defined by the bending shape code and the respective standard.
233;PredefinedType;Subtype of reinforcement element.
234;Role;The role, purpose or usage of the reinforcement, i.e. the kind of loads and stresses it is intended to carry.  Standard values are 'Main', 'Shear', 'Ligature', 'Stud', 'Punching', 'Edge', 'Ring'.
238;PredefinedType;The predefined type is always BAR.
250;PredefinedType;The predefined type is always MESH.
253;NominalDiameter;The nominal diameter defining the cross-section size of the reinforcing bar.
254;CrossSectionArea;The effective cross-section area of the reinforcing bar.
255;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.
"
256;BarSurface;"Indicator for whether the bar surface is plain or textured.
"
257;PredefinedType;The predefined type is always BAR.
259;MeshLength;The overall length of the mesh measured in its longitudinal direction.
260;MeshWidth;The overall width of the mesh measured in its transversal direction.
261;LongitudinalBarNominalDiameter;The nominal diameter denoting the cross-section size of the longitudinal bars.
262;TransverseBarNominalDiameter;The nominal diameter denoting the cross-section size of the transverse bars.
263;LongitudinalBarCrossSectionArea;The effective cross-section area of the longitudinal bars of the mesh.
264;TransverseBarCrossSectionArea;The effective cross-section area of the transverse bars of the mesh.
265;LongitudinalBarSpacing;"The spacing between the longitudinal bars.  Note: an even distribution of bars is presumed; other cases are handled by classification or property sets."
266;TransverseBarSpacing;"The spacing between the transverse bars.  Note: an even distribution of bars is presumed; other cases are handled by classification or property sets."
267;PredefinedType;The predefined type is always MESH.
272;DefinitionType;Descriptive type name applied to reinforcement definition properties.
273;ReinforcementSectionDefinitions;The list of section reinforcement properties attached to the reinforcement definition properties.
285;Name;"<EPM-HTML>
The string by which the pre defined item is identified. Allowable values for the string are declared at the level of subtypes.
</EPM-HTML>"
293;FontFamily;"<EPM-HTML>
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.<br>
</EPM-HTML>"
294;FontStyle;"<EPM-HTML>
The font style property selects between normal (sometimes referred to as ""roman"" or ""upright""), italic and oblique faces within a font family.<br>
</EPM-HTML>"
295;FontVariant;"<EPM-HTML>
The font variant property selects between normal and small-caps.
  <blockquote> <small>NOTE&nbsp; It has been introduced for later compliance to full CSS1 support.</small></blockquote>
</EPM-HTML>"
296;FontWeight;"<EPM-HTML>
The font weight property selects the weight of the font.
  <blockquote> <small>NOTE&nbsp; Values other then 'normal' and 'bold' have been introduced for later compliance to full CSS1 support.</small></blockquote>
</EPM-HTML>"
297;FontSize;"<EPM-HTML>
The font size provides the size or height of the text font.
  <blockquote> <small>NOTE&nbsp; The following values are allowed, <<i>IfcLengthMeasure<i>, with positive values, the length unit is globally defined at <i>IfcUnitAssignment</i>.</small></blockquote>
</EPM-HTML>"
309;Name;"<EPM-HTML>
Optional name given to a particular colour specification in addition to the colour components (like the RGB values).
<blockquote><small>
  NOTE&nbsp; Examples are the names of a industry colour classification, such as RAL.<br>
<font color=""#FF0000"">IFC2x Edition 3 CHANGE&nbsp; Attribute added.
</font></small></blockquote>
</EPM-HTML>"
311;Red;"<EPM-HTML>
The intensity of the red colour component.
<blockquote><small>
NOTE&nbsp; The colour component value is given within the range of 0..1, and not within the range of 0..255 as otherwise usual.
</small></blockquote>
</EPM-HTML>"
312;Green;"<EPM-HTML>
The intensity of the green colour component.
<blockquote><small>
NOTE&nbsp; The colour component value is given within the range of 0..1, and not within the range of 0..255 as otherwise usual.
</small></blockquote>
</EPM-HTML>"
313;Blue;"<EPM-HTML>
The intensity of the blue colour component.
<blockquote><small>
NOTE&nbsp; The colour component value is given within the range of 0..1, and not within the range of 0..255 as otherwise usual.
</small></blockquote>
</EPM-HTML>"
316;SizeInX;"<EPM-HTML>
The extent in the direction of the x-axis.
</EPM-HTML>"
317;SizeInY;"<EPM-HTML>
The extent in the direction of the y-axis.
</EPM-HTML>"
319;Placement;"<EPM-HTML>
The <i>IfcAxis2Placement</i> 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.
  <blockquote> <small>NOTE&nbsp; In case of a 3D placement by <i>IfcAxisPlacement3D the <i>IfcPlanarBox</i> is defined within the xy plane of the definition coordinate system.</small></blockquote>
</EPM-HTML>"
325;DependingProperty;"<EPM-HTML>
The property on which the relationship depends.
</EPM-HTML>"
326;DependantProperty;"<EPM-HTML>
The dependant property.
</EPM-HTML>"
327;Expression;Expression that further describes the nature of the dependency relation.
332;Name;"<EPM-HTML>
Name for this property. This label is the significant name string that defines the semantic meaning for the property.
</EPM-HTML>"
333;Description;"<EPM-HTML>
Informative text to explain the property.
</EPM-HTML>"
334;PartOfPset;"<EPM-HTML>
Reference to the <i>IfcPropertySet</i> by which the <i>IfcProperty</i> is referenced.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; New inverse attribute to navigate from <i>IfcProperty</i> to <i>IfcPropertySet</i> with upward compatibility for file based exchange.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
335;HasExternalReferences;"<EPM-HTML>
Reference to an external reference, e.g. library, classification, or document information, that is associated to the property.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE New inverse attribute.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
336;PropertyForDependance;The property on whose value that of another property depends.
337;PropertyDependsOn;The relating property on which the value of the property depends.
338;PartOfComplex;"<EPM-HTML>
Reference to the <i>IfcComplexProperty</i> in which the <i>IfcProperty</i> is contained.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The cardinality has changed to 0..n to allow reuse of instances of <i>IfcProperty</i> in several <i>IfcComplexProperty</i> with upward compatibility for file based exchange.
</font></small></blockquote>
</EPM-HTML>"
340;UsageName;"<EPM-HTML>Usage description of the <I>IfcComplexProperty</I> within the property set which references the <I>IfcComplexProperty</I>.
<BLOCKQUOTE> <FONT SIZE=""-1"">NOTE: Consider a complex property for glazing properties. The <I>Name</I> attribute of the <I>IfcComplexProperty</I> could be <I>Pset_GlazingProperties</I>, and the UsageName attribute could be <I>OuterGlazingPane</I>.</FONT></BLOCKQUOTE>
</EPM-HTML>
"
341;HasProperties;"<EPM-HTML>
Set of properties that can be used within this complex property (may include other complex properties).
</EPM-HTML>"
352;NominalValue;"<EPM-HTML>
Value and measure type of this property. 
<blockquote><small>
NOTE&nbsp; By virtue of the defined data type, that is selected from the SELECT <i>IfcValue</i>, the appropriate unit can be found within the <i>IfcUnitAssignment</i>, defined for the project if no value for the unit attribute is given.<br>
<font color=""#ff0000"">
IFC2x3 CHANGE&nbsp; The attribute has been made optional with upward compatibility for file based exchange.
</font>
</small></blockquote>
</EPM-HTML>"
353;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.
355;EnumerationValues;"<EPM-HTML>
Enumeration values, which shall be listed in the referenced <i>IfcPropertyEnumeration</i>, if such a reference is provided.
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been made optional with upward compatibility for file based exchange.
  </font></small>
</blockquote>
</EPM-HTML>"
356;EnumerationReference;Enumeration from which a enumeration value has been selected. The referenced enumeration also establishes the unit of the enumeration value.
359;Name;Name of this enumeration.
360;EnumerationValues;List of values that form the enumeration.
361;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.
366;UpperBoundValue;"<EPM-HTML>
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 <i>LowerBoundValue</i>).
</EPM-HTML>"
367;LowerBoundValue;"<EPM-HTML>
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 <i>UpperBoundValue</i>).
</EPM-HTML>"
368;Unit;"<EPM-HTML>
Unit for the upper and lower bound values, if not given, the default value for the measure type is used as defined by the global unit assignment at <i>IfcProject.UnitInContext</i>. The applicable unit is then selected by the underlying TYPE of the <i>UpperBoundValue</i>, <i>LowerBoundValue</i>, and <i>SetPointValue</i>)
</EPM-HTML>"
369;SetPointValue;"<EPM-HTML>
Set point value as typically used for operational value setting.
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been added at the end of the attribute list.
  </font></small>
</blockquote>
</EPM-HTML>"
374;DefiningValues;"<EPM-HTML>
List of defining values, which determine the defined values. This list shall have unique values only.
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been made optional with upward compatibility for file based exchange.
  </font></small>
</blockquote>
</EPM-HTML>"
375;DefinedValues;"<EPM-HTML>
Defined values which are applicable for the scope as defined by the defining values.
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been made optional with upward compatibility for file based exchange.
  </font></small>
</blockquote>
</EPM-HTML>"
376;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.
377;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.
378;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.
379;CurveInterpolation;"<EPM-HTML>
Interpolation of the curve between two defining and defined values that are provided. if not provided a linear interpolation is assumed.
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been added at the end of the attribute list.
  </font></small>
</blockquote>
</EPM-HTML>"
389;UsageName;Description of the use of the referenced value within the property.
390;PropertyReference;"<EPM-HTML>
Reference to another property entity through one of the select types in the <i>IfcObjectReferenceSelect</i>.
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been made optional with upward compatibility for file based exchange.
  </font></small>
</blockquote>
</EPM-HTML>"
401;ListValues;"<EPM-HTML>
List of property values.
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been made optional with upward compatibility for file based exchange.
  </font></small>
</blockquote>
</EPM-HTML>"
402;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.
409;Name;Name of the element quantity or measure. The name attribute has to be made recognizable by further agreements.
410;Description;Further explanation that might be given to the quantity.
411;HasExternalReferences;"<EPM-HTML>
Reference to an external reference, e.g. library, classification, or document information, that is associated to the quantity.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE New inverse attribute.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
412;PartOfComplex;Reference to a physical complex quantity in which the physical quantity may be contained.
420;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.
422;LengthValue;Length measure value of this quantity.
423;Formula;"<EPM-HTML>
A formula by which the quantity has been calculated. It can be assigned in addition to the actual value of the quantity. Formulas could be mathematic calculations (like width x height), database links, or a combination. The formula is for informational purposes only.
<blockquote>
<small><font color=""ff0000"">IFC2x4 CHANGE  Attribute added to the end of the attribute list.
</font></small>
</blockquote>
</EPM-HTML>"
427;AreaValue;Area measure value of this quantity.
428;Formula;"<EPM-HTML>
A formula by which the quantity has been calculated. It can be assigned in addition to the actual value of the quantity. Formulas could be mathematic calculations (like width x height), database links, or a combination. The formula is for informational purposes only.
<blockquote>
<small><font color=""ff0000"">IFC2x4 CHANGE  Attribute added to the end of the attribute list.
</font></small>
</blockquote>
</EPM-HTML>"
432;VolumeValue;Volume measure value of this quantity.
433;Formula;"<EPM-HTML>
A formula by which the quantity has been calculated. It can be assigned in addition to the actual value of the quantity. Formulas could be mathematic calculations (like width x height), database links, or a combination. The formula is for informational purposes only.
<blockquote>
<small><font color=""ff0000"">IFC2x4 CHANGE  Attribute added to the end of the attribute list.
</font></small>
</blockquote>
</EPM-HTML>"
437;CountValue;Count measure value of this quantity.
438;Formula;"<EPM-HTML>
A formula by which the quantity has been calculated. It can be assigned in addition to the actual value of the quantity. Formulas could be mathematic calculations (like width x height), database links, or a combination. The formula is for informational purposes only.
<blockquote>
<small><font color=""ff0000"">IFC2x4 CHANGE  Attribute added to the end of the attribute list.
</font></small>
</blockquote>
</EPM-HTML>"
441;WeightValue;Mass measure value of this quantity.
442;Formula;"<EPM-HTML>
A formula by which the quantity has been calculated. It can be assigned in addition to the actual value of the quantity. Formulas could be mathematic calculations (like width x height), database links, or a combination. The formula is for informational purposes only.
<blockquote>
<small><font color=""ff0000"">IFC2x4 CHANGE  Attribute added to the end of the attribute list.
</font></small>
</blockquote>
</EPM-HTML>"
446;TimeValue;Time measure value of this quantity.
447;Formula;"<EPM-HTML>
A formula by which the quantity has been calculated. It can be assigned in addition to the actual value of the quantity. Formulas could be mathematic calculations (like width x height), database links, or a combination. The formula is for informational purposes only.
<blockquote>
<small><font color=""ff0000"">IFC2x4 CHANGE  Attribute added to the end of the attribute list.
</font></small>
</blockquote>
</EPM-HTML>"
451;HasQuantities;Set of physical quantities that are grouped by this complex physical quantity according to a given discrimination.
452;Discrimination;Identification of the discrimination by which this physical complex property is distinguished. Examples of discriminations are 'layer', 'steel bar diameter', etc.
453;Quality;Additional indication of a quality of the quantities that are grouped under this physical complex quantity.
454;Usage;Additional indication of a usage type of the quantities that are grouped under this physical complex quantity.
463;ServicesBuildings;"<EPM-HTML>Reference to the <strike>building</strike> spatial structure via the objectified relationship <i>IfcRelServicesBuildings</i>, which is serviced by the system.
</EPM-HTML>
"
465;LongName;"<EPM-HTML>
Long name for a zone, used for informal purposes. It should be used, if available, in conjunction with the inherited <i>Name</i> attribute.
<blockquote>
  <small>NOTE  In many scenarios the <i>Name</i> attribute refers to the short name or number of a zone, and the <i>LongName</i> refers to the full name.
  </small>
</br>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE The attribute has been added at the end of the entity definition.</font>
  </small>
</blockquote>
</EPM-HTML>"
470;ConnectionGeometry;"<EPM-HTML>
The geometric shape representation of the connection geometry that is provided in the object coordinate system of the <i>RelatingElement</i> (mandatory) and in the object coordinate system of the <i>RelatedElement</i> (optionally).
</EPM-HTML>"
471;RelatingElement;"<EPM-HTML>
Reference to a subtype of <i>IfcElement</i> that is connected by the connection relationship in the role of <i>RelatingElement</i>.
</EPM-HTML>
"
472;RelatedElement;"<EPM-HTML>
Reference to a subtype of <i>IfcElement</i> that is connected by the connection relationship in the role of <i>RelatedElement</i>.
</EPM-HTML>"
477;RelatingSpace;Reference to one spaces that is delimited by this boundary.
478;RelatedBuildingElement;"<EPM-HTML>
Reference to <strike>Building</strike> Element, that defines the Space Boundaries.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x PLATFORM CHANGE&nbsp; The data type has been changed from <i>IfcBuildingElement</i> to <i>IfcElement</i> with upward compatibility for file based exchange.
    </font>
  </small>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been changed to be mandatory.
    </font>
  </small>
</blockquote>
</EPM-HTML>
"
479;ConnectionGeometry;"<EPM-HTML>
Physical representation of the space boundary. Provided as a <u>curve or</u> surface given within the LCS of the space.
<blockquote><small><font color=""#ff0000"">
IFC2x PLATFORM CHANGE&nbsp; The data type has been changed from <i>IfcConnectionSurfaceGeometry</i> to <i>IfcConnectionGeometry</i> with upward compatibility for file based exchange.
</font></small></blockquote>
</EPM-HTML>
"
480;PhysicalOrVirtualBoundary;"Defines, whether the Space Boundary is physical (Physical) or virtual (Virtual).
"
481;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).
"
484;ParentBoundary;"<EPM-HTML>
Reference to the host, or parent, space boundary within which this inner boundary is defined.
</EPM-HTML>"
485;InnerBoundaries;"<EPM-HTML>
Reference to the inner boundaries of the space boundary. Inner boundaries are defined by the space boundaries of openings, doors and windows.
</EPM-HTML>"
487;ParentBoundary;"<EPM-HTML>
Reference to the host, or parent, space boundary within which this inner boundary is defined.
</EPM-HTML>"
488;CorrespondingBoundary;"<EPM-HTML>
Reference to the other space boundary of the pair of two space boundaries on either side of a space separating thermal boundary element.
</EPM-HTML>"
489;Corresponds;"<EPM-HTML>
Reference to the other space boundary of the pair of two space boundaries on either side of a space separating thermal boundary element.
</EPM-HTML>"
490;InnerBoundaries;"<EPM-HTML>
Reference to the inner boundaries of the space boundary. Inner boundaries are defined by the space boundaries of openings, doors and windows.
</EPM-HTML>"
495;PredefinedType;"<EPM-HTML>
Predefined generic types for a space that are specified in an enumeration. There might be property sets defined specifically for each predefined type.

<blockquote>
  <small>
Previous use, prior to IFC2x4, had been to indicates whether the <i>IfcSpace</i> is an interior space by value INTERNAL, or an exterior space by value EXTERNAL. This use is now deprecated, the property 'IsExternal' at 'Pset_SpaceCommon' should be used instead. 
  </small>
</blockquote>

<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been renamed from <i>ExteriorOrInteriorSpace</i> with upward compatibility for file based exchange.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
496;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."
497;HasCoverings;"<EPM-HTML>
Reference to <i>IfcCovering</i> by virtue of the objectified relationship <i>IfcRelCoversSpaces</i>. It defines the concept of a space having coverings assigned. Those coverings may represent different flooring, or tiling areas.

<blockquote><small>

NOTE&nbsp; Coverings are often managed by the space, and not by the building element, which they cover.<br>

<font color=""#ff0000"">IFC2x Edition3 CHANGE&nbsp; New inverse relationship. Upward compatibility for file based exchange is guaranteed.</font>

</small></blockquote>

</EPM-HTML>"
498;BoundedBy;"<EPM-HTML>
Reference to a set of <i>IfcRelSpaceBoundary</i>'s that defines the physical or virtual delimitation of that space against physical or virtual boundaries.
</EPM-HTML>"
506;CompositionType;"<EPM-HTML>
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. If no <em>CompositionType</em> is asserted, the dafault value 'ELEMENT' applies.
<blockquote>
  <p>
    <span style=""font-size:smaller;color=red"">
      IFC2x4 CHANGE&nbsp
      Attribute made optional.</span>
  </p>
</blockquote>
</EPM-HTML>"
507;ContainsElements;"<EPM-HTML>
Set of spatial containment relationships, that holds those elements, which are contained within this element of the project spatial structure.
<blockquote><small>
NOTE&nbsp; The spatial containment relationship, established by <i>IfcRelContainedInSpatialStructure</i>, is required to be an hierarchical relationship, i.e. each element can only be assigned to 0 or 1 spatial structure element.
</small></blockquote>
</EPM-HTML>"
513;LongName;"<EPM-HTML>
Long name for a spatial structure element, used for informal purposes. It should be used, if available, in conjunction with the inherited <i>Name</i> attribute.
<blockquote>
  <small>NOTE  In many scenarios the <i>Name</i> attribute refers to the short name or number of a spacial element, and the <i>LongName</i> refers to the full name.
  </small>
</blockquote>
</EPM-HTML>"
514;ServicedBySystems;"<EPM-HTML>
Set of relationships to systems, that provides a certain service to the spatial element for which it is defined. The relationship is handled by the objectified relationship <i>IfcRelServicesBuildings</i>.
<blockquote>
  <small>
<font color=""#ff0000"">IFC2x Edition 4 CHANGE&nbsp; The inverse attribute has been promoted to the new supertype <i>IfcSpatialElement</i> with upward compatibility for file based exchange.</font>
  </small>
</blockquote>
</EPM-HTML>"
515;ReferencesElements;"<EPM-HTML>
Set of spatial reference relationships, that holds those elements, which are referenced, but not contained, within this element of the project spatial structure.
<blockquote>
  <small>
NOTE&nbsp; The spatial reference relationship, established by <i>IfcRelReferencedInSpatialStructure</i>, is not required to be an hierarchical relationship, i.e. each element can be assigned to 0, 1 or many spatial structure elements.
<br><br>
EXAMPLE&nbsp; A curtain wall maybe contained in the ground floor, but maybe referenced in all floors, it reaches.
<br><br>
<font color=""#ff0000"">
IFC2x Edition 3 CHANGE&nbsp; The inverse attribute has been added with upward compatibility for file based exchange.</font>
<br><br>
<font color=""#ff0000"">
IFC2x Edition 4 CHANGE&nbsp; The inverse attribute has been promoted to the new supertype <i>IfcSpatialElement</i> with upward compatibility for file based exchange.</font>
  </small>
</blockquote>
</EPM-HTML>"
525;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.
526;FillsVoids;"<EPM-HTML>
Reference to the <i>IfcRelFillsElement</i> Relationship that puts the element as a filling into the opening created within another element.
</EPM-HTML>

"
527;ConnectedTo;"Reference to the element connection relationship. The relationship then refers to the other element to which this element is connected to.
"
528;IsInterferedByElements;"<EPM-HTML>
Reference to the interference relationship to indicate the element that is interfered. The relationship, if provided, indicates that this element has an interference with one or many other elements.
<blockquote><small>
NOTE  There is no indication of precedence between <i>IsInterferedByElements</i> and <i>InterferesElements</i>. 
</small><br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  New inverse relationship.
</color></small>
</blockquote>
</EPM-HTML>"
529;InterferesElements;"<EPM-HTML>
Reference to the interference relationship to indicate the element that interferes. The relationship, if provided, indicates that this element has an interference with one or many other elements.
<blockquote><small>
NOTE  There is no indication of precedence between <i>IsInterferedByElements</i> and <i>InterferesElements</i>. 
</small><br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  New inverse relationship.
</color></small>
</blockquote>
</EPM-HTML>"
530;HasProjections;"<EPM-HTML>
Projection relationship that adds a feature (using a Boolean union) to the <I>IfcBuildingElement</I>.
</EPM-HTML>"
531;ReferencedInStructures;"<EPM-HTML>
Reference relationship to the spatial structure element, to which the element is additionally associated. This relationship may not be hierarchical, an element may be referenced by zero, one or many spatial structure elements.
<blockquote><font color=""#ff0000""><small>
IFC2x Edition 3 CHANGE&nbsp; The inverse attribute has been added with upward compatibility for file based exchange.
<small></font></blockquote>
</EPM-HTML>"
532;HasOpenings;"<EPM-HTML>
Reference to the <i>IfcRelVoidsElement</i> relationship that creates an opening in an element. An element can incorporate zero-to-many openings. For each opening, that voids the element, a new relationship <i>IfcRelVoidsElement</i> is generated.
</EPM-HTML>
"
533;IsConnectionRealization;"<EPM-HTML>
Reference to the connection relationship with realizing element. The relationship, if provided, assigns this element as the realizing element to the connection, which provides the physical manifestation of the connection relationship.
</EPM-HTML>
"
534;ProvidesBoundaries;"<EPM-HTML>
Reference to space boundaries by virtue of the objectified relationship <i>IfcRelSpaceBoundary</i>. It defines the concept of an element bounding spaces.
</EPM-HTML>
"
535;ConnectedFrom;"Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element.
"
536;ContainedInStructure;"<EPM-HTML>
Containment relationship to the spatial structure element, to which the element is primarily associated. This containment relationship has to be hierachical, i.e. an element may only be assigned directly to zero or one spatial structure. 
</EPM-HTML>"
538;HasCoverings;"<EPM-HTML>
Reference to <i>IfcCovering</i> by virtue of the objectified relationship <i>IfcRelCoversBldgElement</i>. It defines the concept of a building element having coverings associated.
</EPM-HTML>"
544;HasPorts;"<EPM-HTML>
Reference to the element to port connection relationship. The relationship then refers to the port which is contained in this element.

<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The inverse attribute has been demoted from <i>IfcElement</i>.
    </font>
  </small>
</blockquote>

</EPM-HTML>"
548;HasPorts;"<EPM-HTML>
Reference to the element type to port connection relationship. The relationship then refers to the port which is contained in this element type.

<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; New inverse attribute.
    </font>
  </small>
</blockquote>

</EPM-HTML>"
556;ElementType;"<EPM-HTML>
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. 
</EPM-HTML>"
560;ElementType;"<EPM-HTML>
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. 
</EPM-HTML>"
564;PredefinedType;"<EPM-HTML>
Predefined types to define the particular type of space. There may be property set definitions available for each predefined type.
</EPM-HTML>"
575;PredefinedType;"<EPM-HTML>
Predefined types to define the particular type of the spatial zone. There may be property set definitions available for each predefined type.
</EPM-HTML>"
591;PredefinedType;"<EPM-HTML>
Predefined types to define the particular type of the transport element. There may be property set definitions available for each predefined type.
</EPM-HTML>"
602;PredefinedType;"<EPM-HTML>
Predefined types to define the particular type of the geographic element. There may be property set definitions available for each predefined type.
</EPM-HTML>"
608;PredefinedType;"<EPM-HTML>
Predefined types to define the particular type of the transport element. There may be property set definitions available for each predefined type.
</EPM-HTML>"
623;RelatingPort;Reference to an Port that is connected by the objectified relationship.
624;RelatedElement;"<EPM-HTML>
Reference to an <i>IfcElement</i>, or <i>IfcElementType</i> that has ports assigned.
<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  Data type extended to <i>IfcObjectDefinition</i> to enable elements and element types for the port relationship.
</font></small>
</blockquote>
</EPM-HTML>"
627;ContainedIn;"Reference to the element to port connection relationship. The relationship then refers to the element in which this port is contained.
"
628;ConnectedFrom;Reference to a port that is connected by the objectified relationship.
629;ConnectedTo;Reference to the port connection relationship. The relationship then refers to the other port to which this port is connected.
631;RelatingPort;Reference to the first port that is connected by the objectified relationship.
632;RelatedPort;Reference to the second port that is connected by the objectified relationship.
633;RealizingElement;Defines the element that realizes a port connection relationship.
639;PredefinedType;"<EPM-HTML>
Predefined generic types for a transportation element that are specified in an enumeration. There might be property sets defined specifically for each predefined type.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been changed to be optional.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
640;CapacityByWeight;Capacity of the transport element measured by weight.
641;CapacityByNumber;Capacity of the transportation element measured in numbers of person.
649;ProjectsElements;"<EPM-HTML>
Reference to the <I>IfcRelProjectsElement</I> relationship that uses this <I>IfcFeatureElementAddition</I> to create a volume addition at an element. The <I>IfcFeatureElementAddition</I> can only be used to create a single addition at a single element using Boolean addition operation.
</EPM-HTML>"
651;PredefinedType;"<EPM-HTML>
Predefined generic type for a projection element that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> 
  <small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small>
</blockquote>
</EPM-HTML>"
656;RelatingElement;"<EPM-HTML>
Element at which a projection is created by the associated <I>IfcProjectionElement</I>.
</EPM-HTML>"
657;RelatedFeatureElement;"<EPM-HTML>
Reference to the <I>IfcFeatureElementAddition</I> 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.
</EPM-HTML>"
659;RelatingElement;"<EPM-HTML>
Reference to <strike>building</strike> element in which a void is created by associated <strike>opening</strike> feature subtraction element.
<blockquote>
  <p>
    <span style=""font-size:smaller;color=red"">
IFC2x PLATFORM CHANGE&nbsp; The data type has been changed from <em>IfcBuildingElement</em> to <em>IfcElement</em> with upward compatibility for file based exchange.</span><br>
    <span style=""font-size:smaller;color=red"">
IFC2x4 CHANGE&nbsp
Renamed to <em>RelatingElement</em>.</span>
  </p>
</blockquote>
</EPM-HTML>
"
660;RelatedOpening;"<EPM-HTML>
Reference to the <strike>opening</strike> feature subtraction element which defines a void in the associated <strike>opening</strike> element.
<blockquote>
  <p>
    <span style=""font-size:smaller;color=red"">
IFC2x PLATFORM CHANGE&nbsp; The data type has been changed from <em>IfcOpeningElement</em> to <em>IfcFeatureElementSubtraction</em> with upward compatibility for file based exchange.</span><br>
    <span style=""font-size:smaller;color=red"">
IFC2x4 CHANGE&nbsp
Renamed to <em>RelatedOpening</em>.</span>
  </p>
</blockquote>


</EPM-HTML>"
663;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.
"
668;PredefinedType;"<EPM-HTML>
Predefined generic type for an opening that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> 
  <small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small>
</blockquote>
</EPM-HTML>"
669;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.
"
677;RelatingOpeningElement;"Opening Element being filled by virtue of this relationship.
"
678;RelatedBuildingElement;"<EPM-HTML>
Reference to <strike>building</strike> element that occupies fully or partially the associated opening.
<blockquote><small><font color=""#ff0000"">
IFC2x PLATFORM CHANGE: The data type has been changed from <i>IfcBuildingElement</i> to <i>IfcElement</i> with upward compatibility for file based exchange.
</font><small></blockquote>
</EPM-HTML>"
680;AssemblyPlace;A designation of where the assembly is intended to take place defined by an Enum.
681;PredefinedType;"<EPM-HTML>
Predefined generic types for a element assembly that are specified in an enumeration. There might be property sets defined specifically for each predefined type.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been changed to be optional.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
690;PredefinedType;"<EPM-HTML>
Predefined generic types for a geographic element that are specified in an enumeration. There might be property sets defined specifically for each predefined type.
</EPM-HTML>"
694;RelatingElement;"<EPM-HTML>
Reference to a subtype of <i>IfcElement</> that is the <i>RelatingElement</i> in the interference relationship. Depending on the value of <i>ImpliedOrder</i> the <i>RelatingElement</i> may carry the notion to be the element from which the interference geometry should be subtracted.
</EPM-HTML>"
695;RelatedElement;"<EPM-HTML>
Reference to a subtype of <i>IfcElement</> that is the <i>RelatedElement</i> in the interference relationship. Depending on the value of <i>ImpliedOrder</i> the <i>RelatedElement</i> may carry the notion to be the element from which the interference geometry should not be subtracted.
</EPM-HTML>"
696;InterferenceGeometry;"<EPM-HTML>
The geometric shape representation of the interference geometry that is provided in the object coordinate system of the <i>RelatingElement</i> (mandatory) and in the object coordinate system of the <i>RelatedElement</i> (optionally).
</EPM-HTML>"
697;InterferenceType;"<EPM-HTML>
Optional identifier that describes the nature of the interference. Examples could include 'Clash', 'ProvisionForVoid', etc.
</EPM-HTML>"
698;ImpliedOrder;"<EPM-HTML>
Logical value indicating whether the interference geometry should be subtracted from the <i>RelatingElement</i> (if TRUE), or whether it should be either subtracted from the <i>RelatingElement</i> or the <i>RelatedElement</i> (if FALSE), or whether no indication can be provided (if UNKNOWN).
</EPM-HTML>"
701;RelatedElements;"<EPM-HTML>
Set of products, which are referenced within this level of the spatial structure hierarchy.
<blockquote><small>NOTE&nbsp; 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.</small>
</blockquote>
</EPM-HTML>"
702;RelatingStructure;"<EPM-HTML>
Spatial structure element, within which the element is referenced. Any element can be contained within zero, one or many elements of the project spatial and zoning structure.
<blockquote>
  <small>
<font color=""#ff0000"">IFC2x Edition 4 CHANGE&nbsp; The attribute <i>relatingStructure</i> as been promoted to the new supertype <i>IfcSpatialElement</i> with upward compatibility for file based exchange.</font>
  </small>
</blockquote>
</EPM-HTML>"
705;RealizingElements;Defines the elements that realize a connection relationship.
706;ConnectionType;The type of the connection given for informal purposes, it may include labels, like 'joint', 'rigid joint', 'flexible joint', etc.
708;RelatedElements;"<EPM-HTML>
Set of <strike>elements</strike> products, which are contained within this level of the spatial structure hierarchy.
<blockquote><font color=""#ff0000""><small>
IFC2x PLATFORM CHANGE&nbsp; The data type has been changed from <i>IfcElement</i> to <i>IfcProduct</i> with upward compatibility
<small></font></blockquote>
</EPM-HTML>
"
709;RelatingStructure;"<EPM-HTML>
Spatial structure element, within which the element is contained. Any element can only be contained within one element of the project spatial structure.
</EPM-HTML>"
712;UAxes;List of grid axes defining the first row of grid lines.
713;VAxes;List of grid axes defining the second row of grid lines.
714;WAxes;List of grid axes defining the third row of grid lines. It may be given in the case of a triangular grid.
715;ContainedInStructure;"<EPM-HTML>
Relationship to a spatial structure element, to which the grid is primarily associated.
<blockquote><small><font color=""#FF0000"">IFC2x PLATFORM CHANGE&nbsp; The inverse relationship has been added to <I>IfcGrid</I> with upward compatibility</font>
</small></blockquote>
</EPM-HTML>"
718;ContainedInStructure;Relationship to a spatial structure element, to which the associate is primarily associated.
720;PredefinedType;"<EPM-HTML>
Predefined types to define the particular type of the spatial zone. There may be property set definitions available for each predefined type.
</EPM-HTML>"
726;PredefinedType;"<EPM-HTML>
Predefined generic types for an external spatial element that are specified in an enumeration. There might be property sets defined specifically for each predefined type.
</EPM-HTML>"
727;BoundedBy;"<EPM-HTML>
Reference to a set of <i>IfcRelSpaceBoundary</i>'s that defines the physical or virtual delimitation of that external spacial element against physical or virtual boundaries.
</EPM-HTML>"
736;RelatingSystem;"System that services the Buildings. 
"
737;RelatedBuildings;"<EPM-HTML>
Spatial structure elements (including site, building, storeys) that are serviced by the system.
<blockquote>
  <small>
<font color=""#FF0000"">IFC2x PLATFORM CHANGE&nbsp; The data type has been changed from <i>IfcBuilding</i> to <i>IfcSpatialStructureElement</i> with upward compatibility for file based exchange.</font>
<br><br>
<font color=""#FF0000"">IFC2x Edition 4 CHANGE&nbsp; The data type has been changed from <i>IfcSpatialStructureElement</i> to <i>IfcSpatialElement</i> with upward compatibility for file based exchange.
  </small>
</blockquote>
</EPM-HTML>"
739;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.
740;ElevationOfTerrain;Elevation above the minimal terrain level around the foot print of the building, given in elevation above sea level.
741;BuildingAddress;Address given to the building for postal purposes.
743;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.
745;RefLatitude;"<EPM-HTML>
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.
<BLOCKQUOTE> <FONT SIZE=""-1"">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.</FONT></BLOCKQUOTE>
</EPM-HTML>"
746;RefLongitude;"<EPM-HTML>
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.
<BLOCKQUOTE> <font size=""-1"">Longitudes are measured relative to the geodetic zero meridian, nominally the same as the Greenwich prime meridian: longitudes west of the zero meridian have negative values - from 0 till -180, longitudes east of the zero meridian have positive values - from 0 till -180.</font><br>
<font size=""-1"">Example: Chicago Harbor Light has according to WGS84 a longitude -87.35.40 (or 87.35.40W) and a latitude 41.53.30 (or 41.53.30N).</font>
</BLOCKQUOTE>
</EPM-HTML>"
747;RefElevation;"Datum elevation relative to sea level.
"
748;LandTitleNumber;The land title number (designation of the site within a regional system).
749;SiteAddress;Address given to the site for postal purposes.
766;MethodOfMeasurement;"<EPM-HTML>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.

<BLOCKQUOTE> <FONT COLOR=""#FF0000"" SIZE=""-1"">IFC2x2 Addendum 1 change: The attribute has been changed to be optional </FONT></BLOCKQUOTE>
</EPM-HTML>"
767;Quantities;The individual quantities for the element, can be a set of length, area, volume, weight or count based quantities.
771;RelatingMaterial;"<EPM-HTML>
Material definition assigned to the elements or element types. 
</EPM-HTML>"
778;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.
779;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.
780;ReferencedBy;"<EPM-HTML>
Reference to the <i>IfcRelAssignsToProduct</i> relationship, by which other products, processes, controls, resources or actors (as subtypes of <i>IfcObjectDefinition</i>) can be related to this product.
</EPM-HTML>"
789;ObjectType;"<EPM-HTML>
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 <i>PredefinedType</i> is set to USERDEFINED. 
<br>
</EPM-HTML>"
790;IsDeclaredBy;"<EPM-HTML>
Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated <i>IfcObject</i>, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring <i>IfcObject</i>, or its subtypes. 
<blockquote>
<small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; New inverse relationship, change made with upward compatibility for file based exchange.
</font></small>
</blockquote>
</EPM-HTML>"
791;Declares;"<EPM-HTML>
Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated <i>IfcObject</i>, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring <i>IfcObject</i>, or its subtypes. 
<blockquote>
<small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; New inverse relationship, change made with upward compatibility for file based exchange.
</font></small>
</blockquote>
</EPM-HTML>"
792;IsTypedBy;"<EPM-HTML>
Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated <i>IfcTypeObject</i>, or its subtypes, contains the specific information (or type, or style), that is common to all instances of <i>IfcObject</i>, or its subtypes, referring to the same type. 
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; New inverse relationship, the link to <i>IfcRelDefinesByType</i> had previously be included in the inverse relationship <i>IfcRelDefines</i>. Change made with upward compatibility for file based exchange.
</font></small></blockquote>
</EPM-HTML>"
793;IsDefinedBy;"<EPM-HTML>
Set of relationships to property set definitions attached to this object. Those statically or dynamically defined properties contain alphanumeric information content that further defines the object. 
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The data type has been changed from <i>IfcRelDefines</i> to <i>IfcRelDefinesByProperties</i> with upward compatibility for file based exchange.
</font></small></blockquote>
</EPM-HTML>"
798;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.
799;Nests;"<EPM-HTML>
References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only).

<blockquote><p><small><span style=""color:#FF0000"">
IFC2x4 CHANGE&nbsp; The inverse attribute datatype has been added and separated from <i>Decomposes</i> defined at <i>IfcObjectDefinition</i>.
</span></small></p></blockquote>

</EPM-HTML>
"
800;IsNestedBy;"<EPM-HTML>
References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).

<blockquote><p><small><span style=""color:#FF0000"">
IFC2x4 CHANGE&nbsp; The inverse attribute datatype has been added and separated from <i>IsDecomposedBy</i> defined at <i>IfcObjectDefinition</i>.
</span></small></p></blockquote>

</EPM-HTML>
"
801;HasContext;"<EPM-HTML>
References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object.

<blockquote><p><small><span style=""color:#FF0000"">
IFC2x4 CHANGE&nbsp; The inverse attribute datatype has been added.
</span></small></p></blockquote>

</EPM-HTML>"
802;IsDecomposedBy;"<EPM-HTML>
References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts).

<blockquote><p><small><span style=""color:#FF0000"">
IFC2x4 CHANGE&nbsp; The inverse attribute datatype has been changed from the supertype <i>IfcRelDecomposes</i> to subtype <i>IfcRelAggregates</i>.
</span></small></p></blockquote>

</EPM-HTML>
"
803;Decomposes;"<EPM-HTML>
References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only).

<blockquote><p><small><span style=""color:#FF0000"">
IFC2x4 CHANGE&nbsp; The inverse attribute datatype has been changed from the supertype <i>IfcRelDecomposes</i> to subtype <i>IfcRelAggregates</i>.
</span></small></p></blockquote>

</EPM-HTML>
"
804;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.
809;GlobalId;"Assignment of a globally unique identifier within the entire software world.
"
810;OwnerHistory;"<EPM-HTML>
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, 

<blockquote>
<small>
NOTE only the last modification in stored - either as addition, deletion or modification.
</small><br>
<small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been changed to be OPTIONAL.
</font></small></blockquote>
</EPM-HTML>"
811;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.
"
812;Description;Optional description, provided for exchanging informative comments.
818;HasContext;
819;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.
823;DefinesType;"<EPM-HTML>
The type object to which the property set is assigned. The property set acts as a shared property set to all occurrences of the type object.
<blockquote>
  <small>
    <font color=""#FF0000"">IFC2x4 CHANGE  The cardinality has been changed from 0:1 to 0:? with upward compatibility for file based exchange.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
824;DefinesOccurrence;"<EPM-HTML>
Reference to the relation to one or many object occurrences that are characterized by the property set definition. A single property set can be assigned to multiple object occurrences.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE Inverse attribute renamed from PropertyDefinitionOf with upward compatibility for file-based exchange.
</font></small></blockquote>
</EPM-HTML>"
826;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.
"
827;IsDefinedBy;"<EPM-HTML>
Relation to the property set template, via the objectified relationship <i>IfcRelDefinesByTemplate</i>, that, if given, provides the definition template for the property set and its properties. 
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; New inverse relationship, change made with upward compatibility for file based exchange.
</font></small></blockquote>
</EPM-HTML>"
831;RelatedPropertySets;"<EPM-HTML>
One or many property sets defined by a single property set template.
</EPM-HTML>"
832;RelatingTemplate;"<EPM-HTML>
Property set template that provides the common definition of related property sets. 
</EPM-HTML>"
852;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.
853;RelatedObjectsType;"<EPM-HTML>
Particular type of the assignment relationship. It can constrain the applicable object types, used within the role of <i>RelatedObjects</i>.
<blockquote><small><font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The attribute is deprecated and shall no longer be used. A NIL value should always be assigned.
</font></small></blockquote>
</EPM-HTML>"
856;RelatingProcess;"<EPM-HTML>
Reference to the process to which the objects are assigned to.
<blockquote><small>
<font color=""#ff0000"">IFC2x4 CHANGE Datatype expanded to include <i>IfcProcess</i> and <i>IfcTypeProcess</i>.</font>
</small></blockquote>
</EPM-HTML>"
857;QuantityInProcess;"<EPM-HTML>
Quantity of the object specific for the operation by this process.
</EPM-HTML>"
863;Identification;"<EPM-HTML>
    An identifying designation given to a process or activity.
    It is the identifier at the occurrence level. 
    <blockquote>
      <small>
        <font color=""#0000ff"">IFC2x4 CHANGE  Attribute promoted from subtypes.</font>
      </small>
    </blockquote>
</EPM-HTML>"
864;LongDescription;"<EPM-HTML>
An extended description or narrative that may be provided.
<blockquote>
  <p>
    <span style=""font-size:smaller;color:red"">
IFC2x4 CHANGE&nbsp; New attribute.
    </span>
  </p>
</blockquote>
</EPM-HTML>"
865;IsPredecessorTo;"<EPM-HTML>
Dependency between two activities, it refers to the subsequent activity for which this activity is the predecessor. The link between two activities can include a link type and a lag time. 
</EPM-HTML>"
866;IsSuccessorFrom;"<EPM-HTML>
Dependency between two activities, it refers to the previous activity for which this activity is the successor. The link between two activities can include a link type and a lag time. 
</EPM-HTML>"
867;OperatesOn;"<EPM-HTML>
Set of relationships to other objects, e.g. products, processes, controls, resources or actors, that are operated on by the process.
</EPM-HTML>"
869;Identification;"<EPM-HTML>
An identifying designation given to a process type.
</EPM-HTML>"
870;LongDescription;"<EPM-HTML>
An long description, or text, describing the activity in detail.
<blockquote><small>
NOTE The inherited <i>SELF\IfcRoot.Description</i> attribute is used as the short description.
</small></blockquote>
</EPM-HTML>"
871;ProcessType;"<EPM-HTML>
The type denotes a particular type that indicates the process 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. 
</EPM-HTML>"
872;OperatesOn;"<EPM-HTML>
Set of relationships to other objects, e.g. products, processes, controls, resources or actors that are operated on by the process type.
<blockquote>
  <small><font color=""#ff0000"">
    IFC2x4 NOTE  New inverse relationship.
  </small></font>
</blockquote>
</EPM-HTML>"
877;ApplicableOccurrence;"<EPM-HTML>
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. The following conventions are used:
<ul>
  <li>The IFC entity name of the applicable occurrence using the IFC naming convention, CamelCase with IFC prefix</li>
  <li>It can be optionally followed by the predefined type after the separator ""/"" (forward slash), using Uupper case</li>
  <li>If one type object is applicable to many occurrence objects, then those occurrence object names should be separate by comma "","" forming a comma separated string.
</ul>
<blockquote>
  <small>EXAMPLE  Refering to a furniture as applicable occurrence entity would be expressed as 'IfcFurnishingElement', refering to a brace as applicable entity would be expressed as 'IfcMember/BRACE', refering to a wall and wall standard case would be expressed as 'IfcWall, IfcWallStandardCase'.</small>
</blockquote>
</EPM-HTML>"
878;HasPropertySets;"<EPM-HTML>
Set <strike>list</strike> of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type.
<blockquote><small><font color=""#ff0000"">
  IFC2x3 CHANGE&nbsp; The attribute aggregate type has been changed from LIST to SET.
</font></small></blockquote>
</EPM-HTML>"
879;Types;Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type.
882;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.
883;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.
884;ReferencedBy;"<EPM-HTML>
Reference to the <i>IfcRelAssignsToProduct</i> relationship, by which other products, processes, controls, resources or actors (as subtypes of <i>IfcObjectDefinition</i>) can be related to this product type.
<blockquote>
  <small><font color=""#ff0000"">
    IFC2x4 NOTE  New inverse relationship.
  </small></font>
</blockquote>
</EPM-HTML>"
887;RelatingProduct;"<EPM-HTML>
Reference to the product or product type to which the objects are assigned to.
<blockquote><small>
<font color=""#ff0000"">IFC2x4 CHANGE Datatype expanded to include <i>IfcProduct</i> and <i>IfcTypeProduct</i>.</font>
</small></blockquote>
</EPM-HTML>"
893;Identification;"<EPM-HTML>
An identifying designation given to a resource type.
</EPM-HTML>"
894;LongDescription;"<EPM-HTML>
An long description, or text, describing the resource in detail.
<blockquote><small>
NOTE The inherited <i>SELF\IfcRoot.Description</i> attribute is used as the short description.
</small></blockquote>
</EPM-HTML>"
895;ResourceType;"<EPM-HTML>
The type denotes a particular type that indicates the resource 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. 
</EPM-HTML>"
896;ResourceOf;"<EPM-HTML>
Set of relationships to other objects, e.g. products, processes, controls, resources or actors to which this resource type is a resource.
<blockquote>
  <small>
    <font color=""#ff0000"">
      IFC2x4 NOTE  New inverse relationship.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
898;RelatingResource;"<EPM-HTML>
Reference to the resource to which the objects are assigned to.
<blockquote>
  <small>
    <font color=""#ff0000"">
      IFC2x4 CHANGE Datatype expanded to include <i>IfcResource</i> and <i>IfcTypeResource</i>.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
904;Identification;"<EPM-HTML>
    An identifying designation given to a resource.
    It is the identifier at the occurrence level. 
    <blockquote>
      <small>
        <font color=""#0000ff"">IFC2x4 CHANGE  Attribute promoted from subtype <i>IfcConstructionResource</i>.</font>
      </small>
    </blockquote>
</EPM-HTML>"
905;LongDescription;"<EPM-HTML>
A detailed description of the resource (e.g. the skillset for a labor resource).  
<blockquote>
  <p>
    <span style=""font-size:smaller;color:red"">
IFC2x4 NOTE:&nbsp; The attribute <i>LongDescription</i> is added replacing the <i>ResourceGroup</i> attribute at subtype <i>IfcConstructionResource</i>.
    </span>
  </p>
</blockquote>
</EPM-HTML>"
906;ResourceOf;"<EPM-HTML>
Set of relationships to other objects, e.g. products, processes, controls, resources or actors, for which this resource object is a resource.
</EPM-HTML>"
908;RelatedObjects;
909;RelatingType;Reference to the type (or style) information for that object or set of objects.
911;RelatingControl;"<EPM-HTML>
Reference to the <i>IfcControl</i> that applies a control upon objects.
</EPM-HTML>"
914;Identification;"<EPM-HTML>
    An identifying designation given to a control
    It is the identifier at the occurrence level. 
    <blockquote>
      <small>
        <font color=""#0000ff"">IFC2x4 CHANGE  Attribute unified by promoting from various subtypes of <i>IfcControl</i>.</font>
      </small>
    </blockquote>
</EPM-HTML>"
915;Controls;"Reference to the relationship that associates the control to the object(s) being controlled.
"
917;RelatingActor;"Reference to the information about the actor. It comprises the information about the person or organization and its addresses.
"
918;ActingRole;"Role of the actor played within the context of the assignment to the object(s).
"
921;TheActor;"Information about the actor.
"
922;IsActingUpon;"Reference to the relationship that associates the actor to an object.
"
925;RelatingGroup;"<EPM-HTML>
Reference to group that contains all assigned group members.
</EPM-HTML>
"
928;Factor;"<EPM-HTML>
Factor provided as a ratio measure that identifies the fraction or weighted factor that applies to the group assignment.
</EPM-HTML>"
930;IsGroupedBy;"<EPM-HTML>
Reference to the relationship <i>IfcRelAssignsToGroup</i> that assigns the one to many group members to the <i>IfcGroup</i> object.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The cardinality has been changed from 1..1 to 0..? in order to allow the exchange of a group concept without having already group members assigned. It now also allows the use of many instances of <i>IfcRelAssignsToGroup</i> to assign the group members. The change has been done with upward compatibility for file based exchange.
</font><small></blockquote>
</EPM-HTML>"
944;RelatingObject;"<EPM-HTML>
The object definition, either an object type or an object occurrence, that represents the aggregation. It is the whole within the whole/part relationship.

<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been demoted from the supertype <i>IfcRelDecomposes</i> and defines the non-ordered aggregation relationship.
</font></small></blockquote>

</EPM-HTML>"
945;RelatedObjects;"<EPM-HTML>
The object definitions, either object occurrences or object types, that are being aggregated. They are defined as the parts in the whole/part relationship. No order is implied between the parts.

<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been demoted from the supertype <i>IfcRelDecomposes</i> and defines the non-ordered set of parts within the aggregation.
</font></small></blockquote>

</EPM-HTML>
"
948;RelatingObject;"<EPM-HTML>
The object definition, either an non-product object type or a non-product object occurrence, that represents the nest. It is the whole within the whole/part relationship.

<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been demoted from the supertype <i>IfcRelDecomposes</i> and defines the ordered nesting relationship.
</font></small></blockquote>

</EPM-HTML>"
949;RelatedObjects;"<EPM-HTML>
The object definitions, either non-product object occurrences or non-product object types, that are being nestes. They are defined as the parts in the ordered whole/part relationship -  i.e. there is an implied order among the parts expressed by the position within the list of <i>RelatedObjects</i>.

<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been demoted from the supertype <i>IfcRelDecomposes</i> and defines the ordered set of parts within the nest.
</font></small></blockquote>

</EPM-HTML>
"
955;RelatedObjects;"<EPM-HTML>
Set of object or property definitions to which the external references or information is associated. It includes object and type objects, property set templates, property templates and property sets and contexts.
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The attribute datatype has been changed from <i>IfcRoot</i> to <i>IfcDefinitionSelect</i>.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
957;RelatingClassification;Classification applied to the objects.
959;RelatingDocument;Document information or reference which is applied to the objects.
961;RelatingLibrary;Reference to a library, from which the definition of the property set is taken.
967;RelatingContext;"<EPM-HTML>
Reference to the <i>IfcProject</i> to which additional information is assigned.
</EPM-HTML>"
968;RelatedDefinitions;"<EPM-HTML>
Set of object or property definitions that are assigned to a context and to which the unit and representation context definitions of that context apply.
</EPM-HTML>"
973;ObjectType;"<EPM-HTML>
The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. 
</EPM-HTML>"
974;LongName;"<EPM-HTML>
Long name for the context as used for reference purposes.
</EPM-HTML>"
975;Phase;"<EPM-HTML>
Current project phase, or life-cycle phase of this project. Applicable values have to be agreed upon by view definitions or implementer agreements.
</EPM-HTML> 
"
976;RepresentationContexts;"<EPM-HTML>
Context of the representations used within the context. When the context is a project and it 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.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been changed to be optional. Change made with upward compatibility for file based exchange.
</font></small></blockquote>
</EPM-HTML>"
977;UnitsInContext;"<EPM-HTML>
Units globally assigned to measure types used within the context.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The attribute has been changed to be optional. Change made with upward compatibility for file based exchange.
</font></small></blockquote>
</EPM-HTML>"
978;Declares;"<EPM-HTML>
Reference to the <em>IfcRelDeclares</em> relationship that assigns the uppermost entities of includes hierarchies to this context instance.
<blockquote>
  <small>
    NOTE&nbsp; the spatial hiearchy is assigned to <em>IfcProject</em> using the <em>IfcRelAggregates</i> relationship. This is a single exception due to compatibility reasons with earlier releases.
  </small>
</blockquote>
</EPM-HTML>"
986;RelatedObjects;"Reference to the objects (or single object) to which the property definition applies.
"
987;RelatingPropertyDefinition;"Reference to the property set definition for that object or set of objects.
"
989;RelatedObjects;"<EPM-HTML>
Objects being part of an object occurrence decomposition, acting as the ""reflecting parts"" in the relationship.
</EPM-HTML>"
990;RelatingObject;"<EPM-HTML>
Object being part of an object type decomposition, acting as the ""declaring part"" in the relationship.
</EPM-HTML>"
992;TemplateType;"<EPM-HTML>
Property set type defining whether the property set is applicable to a type (subtypes of <i>IfcTypeObject</i>), to an occurrence (subtypes of <i>IfcObject</i>), or as a special case to a performance history.<br><br>
The attribute <i>ApplicableEntity</i> may further refine the applicability to a single or multiple entity type(s).
</EPM-HTML>"
993;ApplicableEntity;"<EPM-HTML>
The attribute optionally defines the data type of the applicable type or occurrence object, to which the assigned property set template can relate. If not present, no instruction is given to which type or occurrence object the property set template is applicable. The following conventions are used:
<ul>
  <li>The IFC entity name of the applicable entity using the IFC naming convention, CamelCase with IFC prefix</li>
  <li>It can be optionally followed by the predefined type after the separator ""/"" (forward slash), using upper case</li>
  <li>If a performance history object of a particular distribution object is attributes by the property set template, then the entity name (and potentially amended by the predefined type) is expanded by adding '[PerformanceHistory]'
  <li>If one property set template is applicable to many type and/or occurrence objects, then those object names should be separate by comma "","" forming a comma separated string.
</ul>
<blockquote>
  <small>EXAMPLE  Refering to a boiler type as applicable entity would be expressed as 'IfcBoilerType', refering to a steam boiler type as applicable entity would be expressed as 'IfcBoilerType/STEAM', refering to a wall and wall standard case and a wall type would be expressed as 'IfcWall, IfcWallStandardCase, IfcWallType'.</small>
<blockquote>
  <small>An applicable <i>IfcPerformanceHistory</i> assigned to an occurrence or type object would be indicated by IfcBoilerType[PerformanceHistory], or respectively IfcBoilerType/STEAM[PerformanceHistory].</small>
</blockquote>
</EPM-HTML>"
994;HasPropertyTemplates;"<EPM-HTML>
Set of <i>IfcPropertyTemplate</i>'s that are defined within the scope of the <i>IfcPropertySetTemplate</i>.
</EPM-HTML>"
995;Defines;"<EPM-HTML>
Relation to the property sets, via the objectified relationship <i>IfcRelDefinesByTemplate</i>, that, if given, utilize the definition template. 
</EPM-HTML>"
1004;PartOfComplexTemplate;"<EPM-HTML>
Reference to a complex property templates. It should only be provided, if the <i>PropertyType</i> of the referenced complex property template is set to <small>COMPLEX</small>.
</EPM-HTML>"
1005;PartOfPsetTemplate;"<EPM-HTML>
Reference to the <i>IfcPropertySetTemplate</i> that defines the scope for the <i>IfcPropertyTemplate</i>. A single <i>IfcPropertyTemplate</i> can be defined within the scope of zero, one or many <i>IfcPropertySetTemplate</i>'.
</EPM-HTML>"
1007;UsageName;
1008;TemplateType;
1009;HasPropertyTemplates;"<EPM-HTML>
Reference to a set of property templates. It should only be provided, if the <i>PropertyType</i> is set to <small>COMPLEX</small>.
</EPM-HTML>"
1016;TemplateType;"<EPM-HTML>
Property type defining whether the property template defines a property with a single value, a bounded value, a list value, a table value, an enumerated value, or a reference value. Or the quantity type defining whether the template defines a quantity with a length, area, volume, weight or time value.
<blockquote>
  <small>
    NOTE the value of this property determines the correct use of the <i>PrimaryUnit</i>, <i>SecondaryUnit</i>, <i>PrimaryDataType</i>, <i>SecondaryDataType</i>, and <i>Expression</i> attributes.
  </small>
</blockquote>
</EPM-HTML>"
1017;PrimaryDataType;"<EPM-HTML>
Primary data type assigned to the definition of the property. It should be provided, if the <i>PropertyType</i> is set to:
<ul>
<li><small>P_SINGLEVALUE</small>: determining the data type of <i>IfcPropertySingleValue.NominalValue</i></li>
<li><small>P_ENUMERATEDVALUE</small>: determining the data type of <i>IfcPropertyEnumeratedValue.EnumerationValues</i></li>
<li><small>P_BOUNDEDVALUE</small>: determining the data type of <i>IfcPropertyBoundedValue.LowerBoundValue</i></li>
<li><small>P_LISTVALUE</small>: determining the data type of <i>IfcPropertyListValue.ListValues</i></li>
<li><small>P_TABLEVALUE</small>: determining the data type of <i>IfcPropertyTableValue.DefiningValues</i></li>
<li><small>P_REFERENCEVALUE</small>: determining the data type of <i>IfcPropertyTableValue.PropertyReference</i></li></ul>
<blockquote>
  <p>
    <span style=""font-size:smaller"">The value range of the data type is within the select type <i>IfcValue</i> for all <i>PropertyType</i>'s with the exeption of <small>P_REFERENCEVALUE</small>. Here it is within the select type <i>IfcObjectReferenceSelect</i>.</span>
  </p>
</blockquote>
</EPM-HTML>"
1018;SecondaryDataType;"<EPM-HTML>
Secondary data type assigned to the definition of the property. It should be provided, if the <i>PropertyType</i> is set to:
<ul>
<li><small>P_ENUMERATEDVALUE</small>: determining the values of <i>IfcPropertyEnumeration.EnumerationValues</i> as a comma delimited list</li>
<li><small>P_BOUNDEDVALUE</small>: determining the data type of <i>IfcPropertyBoundedValue.UpperBoundValue</i></li>
<li><small>P_TABLEVALUE</small>: determining the data type of <i>IfcPropertyTableValue.DefinedValues</i></li>
</ul>
The value range of the data type is within the select type <i>IfcValue</i>  for all <i>PropertyType</i>'s with the exeption of <small>P_ENUMERATEDVALUE</small>. Here it is the comma delimited list of enumerators.
<blockquote>
  <small>
    NOTE The data type of <i>IfcPropertyEnumeration.EnumerationValues</i> is provided as <i>PrimaryDataType</i>.
  </small>
</blockquote>
</EPM-HTML>"
1019;PrimaryUnit;"<EPM-HTML>
Primary unit assigned to the definition of the property. It should be provided, if the <i>PropertyType</i> is set to:
<ul>
<li><small>P_SINGLEVALUE</small>: determining the <i>IfcPropertySingleValue.Unit</i></li>
<li><small>P_ENUMERATEDVALUE</small>: determining the <i>IfcPropertyEnumeration.Unit</i></li>
<li><small>P_BOUNDEDVALUE</small>: determining the <i>IfcPropertyBoundedValue.Unit</i></li>
<li><small>P_LISTVALUE</small>: determining the <i>IfcPropertyListValue.Unit</i></li>
<li><small>P_TABLEVALUE</small>: determining the <i>IfcPropertyTableValue.DefiningUnit</i></li>
</ul>
</EPM-HTML>"
1020;SecondaryUnit;"<EPM-HTML>
Secondary unit assigned to the definition of the property. It should be provided, if the <i>PropertyType</i> is set to:
<ul>
<li><small>P_TABLEVALUE</small>: determining the <i>IfcPropertyTableValue.DefinedUnit</i></li>
</ul>
</EPM-HTML>"
1021;Expression;"<EPM-HTML>
The expression used to store additional information for the property template depending on the <i>PropertyType</i>. It should the following definitions, if the <i>PropertyType</i> is set to:
<ul>
<li><small>P_TABLEVALUE</small>: the expression that could be evaluated to define the correlation between the defining values and the defined values.</li>
<li><small>Q_LENGTH, Q_AREA, Q_VOLUME, Q_COUNT, Q_WEIGTH, Q_TIME</small>: the formula to be used to calculate the quantity</li>
</ul>
<blockquote>
  <small>
    NOTE No value shall be asserted if the <i>PropertyType</i> is not listed above.
  </small>
</blockquote>
</EPM-HTML>"
1022;AccessState;"<EPM-HTML>
Information about the access state of the property. It determines whether a property be viewed and/or modified by any receiving application without specific knowledge of it. <br><br>
<b>Attribute use definition for <i>IfcStateEnum</i></b>

<ul>
<li>READWRITE: Properties of this template are readable and writable. They may be viewed and modified by users of any application. These are typical informational properties set by a user.</li>

<li>READONLY: Properties of this template are read-only. They may be viewed but not modified by users of any application. (Applications may generate such values). These are typical automatically generated properties that should be displayed only, but not written back.</li>

<li>LOCKED: Properties of this template are locked. They may only be accessed by the owning application (the publisher of the property set template). These are typically application depended, internal properties that should not be published.</li>

<li>READWRITELOCKED: Properties of this template are locked, readable, and writable. They may only be accessed by the owning application.</li>

<li>READONLYLOCKED: Properties of this template are locked and read-only. They may only be accessed by the owning application. </li>

</ul>
</EPM-HTML>"
1047;ProxyType;"High level (and only) semantic meaning attached to the IfcProxy, defining the basic construct type behind the Proxy, e.g. Product or Process.
"
1048;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.
1056;RelatedControlElements;"References control elements which may be used to impart control on the Distribution Element.
"
1057;RelatingFlowElement;"Relationship to a distribution flow element
"
1059;AssignedToFlowElement;Reference through the relationship object to related distribution flow elements.
1061;FlowDirection;"Enumeration that identifies if this port is a Sink (inlet), a Source (outlet) or both a SinkAndSource.
"
1062;PredefinedType;Enumeration that identifies the system type.  If a system type is defined, the port may only be connected to other ports having the same system type.
1126;PredefinedType;Predefined types of distribution chambers.
1140;LongName;"<EPM-HTML>
Long name for a system, used for informal purposes. It should be used, if available, in conjunction with the inherited <i>Name</i> attribute.
<blockquote>
  <small>NOTE  In many scenarios the <i>Name</i> attribute refers to the short name or number of a distribution system or branch circuit, and the <i>LongName</i> refers to a descriptive name.
  </small>
</blockquote>
</EPM-HTML>"
1141;PredefinedType;Predefined types of distribution systems.
1152;HasControlElements;Reference to the relationship object that relates control elements.
1162;PredefinedType;
1167;PredefinedType;Subtype of discrete accessory
1181;PredefinedType;Subtype of building element part
1189;PredefinedType;Subtype of discrete accessory
1198;PredefinedType;Subtype of fastener
1207;PredefinedType;Subtype of mechanical fastener
1208;NominalDiameter;The nominal diameter describing the cross-section size of the fastener type.
1209;NominalLength;The nominal length describing the longitudinal dimensions of the fastener type.
1225;PredefinedType;Subtype of fastener
1229;PredefinedType;Subtype of building element part
1233;PredefinedType;Subtype of mechanical fastener
1238;RelatingSpace;"<EPM-HTML>
Relationship to the space object that is covered.
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE: The attribute name has been changed from <i>RelatedSpace</i> to <i>RelatingSpace</i> with upward compatibility for file based exchange.
  </font><small>
</blockquote>
</EPM-HTML>"
1239;RelatedCoverings;"Relationship to the set of coverings covering this space.
"
1241;RelatingPriorities;"Priorities for connection. It refers to the layers of the RelatingObject.
"
1242;RelatedPriorities;"Priorities for connection. It refers to the layers of the RelatedObject.
"
1243;RelatedConnectionType;"Indication of the connection type in relation to the path of the RelatingObject.
"
1244;RelatingConnectionType;"Indication of the connection type in relation to the path of the RelatingObject.
"
1252;PredefinedType;"<EPM-HTML>
Predefined generic type for a beam that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcBeamType</i> is assigned, providing its own <i>IfcBeamType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small></blockquote>
</EPM-HTML>"
1268;PredefinedType;"<EPM-HTML>
Predefined generic type for a column that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcColumnType</i> is assigned, providing its own <i>IfcColumnType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small></blockquote>
</EPM-HTML>"
1279;PredefinedType;"<EPM-HTML>
Predefined generic type for a member that is specified in an enumeration. There may be a property set given for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcMemberType</i> is assigned, providing its own <i>IfcMemberType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small></blockquote>
</EPM-HTML>"
1302;PredefinedType;"<EPM-HTML>
Predefined generic type for a wall that is specified in an enumeration. There may be a property set given specifically for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcWallType</i> is assigned, providing its own <i>IfcWallType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small></blockquote>
</EPM-HTML>"
1321;PredefinedType;"<EPM-HTML>
Predefined generic type for a slab that is specified in an enumeration. There may be a property set given specifically for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcSlabType</i> is assigned, providing its own <i>IfcSlabType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">FC2x PLATFORM CHANGE: The attribute has been changed into an OPTIONAL attribute.</font></small></blockquote>
</EPM-HTML>"
1336;PredefinedType;"<EPM-HTML>
Predefined shape types for a ramp that are specified in an enumeration.
<blockquote> 
<small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcRampType</i> is assigned, providing its own <i>IfcRampType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been renamed from ShapeType and changed to be OPTIONAL with upward compatibility for file based exchange.</font></small>
</blockquote>
</EPM-HTML>"
1350;PredefinedType;"<EPM-HTML>
Predefined shape types for a stair that are specified in an enumeration.
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE  The attribute has been renamed from ShapeType and changed to be OPTIONAL with upward compatibility for file based exchange.
  </font><small>
</blockquote>
</EPM-HTML>"
1372;PredefinedType;"<EPM-HTML>
Predefined shape types for a roof that are specified in an enumeration.
<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been renamed from ShapeType and changed to be OPTIONAL with upward compatibility for file based exchange.</font></small>
</blockquote>
</EPM-HTML>"
1393;NumberOfRiser;"<EPM-HTML>
Number of the risers included in the stair flight
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE  The attribute has been deprecated it shall only be exposed with a NIL value. Use Pset_StairFlightCommon.NumberOfRisers instead.
  </font><small>
</EPM-HTML>"
1394;NumberOfTreads;"<EPM-HTML>
Number of treads included in the stair flight.
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE  The attribute has been deprecated it shall only be exposed with a NIL value. Use Pset_StairFlightCommon.NumberOfTreads instead.
  </font><small>
</blockquote>
</EPM-HTML>"
4142;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.
"
4144;EccentricityInX;"<EPM-HTML>
Distance in x direction between the two points (or vertex points) engaged in the point connection.
</EPM-HTML>"
4145;EccentricityInY;"<EPM-HTML>
Distance in y direction between the two points (or vertex points) engaged in the point connection.
</EPM-HTML>"
4146;EccentricityInZ;"<EPM-HTML>
Distance in z direction between the two points (or vertex points) engaged in the point connection.
</EPM-HTML>"
4151;CurveOnRelatingElement;The bounded curve at which the connected objects are aligned at the relating element, given in the LCS of the relating element.
4152;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.
4157;SurfaceOnRelatingElement;Surface at which related object is aligned at the relating element, given in the LCS of the relating element.
4158;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.
"
4164;VolumeOnRelatingElement;"<EPM-HTML>
Volume at which related object overlaps with the relating element, given in the LCS of the relating element.
</EPM-HTML>"
4165;VolumeOnRelatedElement;"<EPM-HTML>
Volume at which related object overlaps with the relating element, given in the LCS of the related element.
</EPM-HTML>"
4170;AxisTag;The tag or name for this grid axis.
4171;AxisCurve;Underlying curve which provides the geometry for this grid axis.
4172;SameSense;Defines whether the original sense of curve is used or whether it is reversed in the context of the grid axis.
4173;PartOfW;"<EPM-HTML>
If provided, the <i>IfcGridAxis</i> is part of the <i>WAxes</i> of <i>IfcGrid</i>.
<blockquote><small>
  <font color=""#FF0000"">IFC2x Edition 3 CHANGE&nbsp; New inverse attribute.</font>
</small></blockquote>
</EPM-HTML>"
4174;PartOfV;"<EPM-HTML>
If provided, the <i>IfcGridAxis</i> is part of the <i>VAxes</i> of <i>IfcGrid</i>.
<blockquote><small>
  <font color=""#FF0000"">IFC2x Edition 3 CHANGE&nbsp; New inverse attribute.</font>
</small></blockquote>
</EPM-HTML>"
4175;PartOfU;"<EPM-HTML>
If provided, the <i>IfcGridAxis</i> is part of the <i>UAxes</i> of <i>IfcGrid</i>.
<blockquote><small>
  <font color=""#FF0000"">IFC2x Edition 3 CHANGE&nbsp; New inverse attribute.</font>
</small></blockquote>
</EPM-HTML>"
4176;HasIntersections;"<EPM-HTML>
The reference to a set of <IfcVirtualGridIntersection</i>'s, that connect other grid axes to this grid axis.
<blockquote><small>
  <font color=""#FF0000"">IFC2x3 CHANGE&nbsp; New inverse attribute.</font>
</small></blockquote>
</EPM-HTML>"
4180;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.
4181;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.
"
4183;PlacementLocation;"<EPM-HTML>
Placement of the object coordinate system defined by the intersection of two grid axes.
</EPM-HTML>
"
4951;Target;A description of the placement, orientation and (uniform or non-uniform) scaling of the defined symbol.
4960;AppliesTextures;"<EPM-HTML>
Reference to the one (or in case of multi textures with identity transformation to geometric surfaces) subtype of <em>IfcSurfaceTexture</em> that is applied to a geometric surface by the texture coordinate transformation.
</EPM-HTML>"
4962;Mode;"<EPM-HTML>
The <em>Mode</em> attribute describes the algorithm used to compute texture coordinates.
<blockquote>
  <p>
    <span ""style:font-size:smaller"">NOTE&nbsp; The applicable values for the <em>Mode</em> attribute are determined by view definitions or implementer agreements. It is recommended to use the modes described in ISO/IES 19775-1.2:2008 X3D Architecture and base components Edition 2, Part 1. See <a href=""http://www.web3d.org/x3d/specifications/ISO-IEC-19775-1.2-X3D-AbstractSpecification/Part01/components/texturing.html#TextureCoordinateGenerator"">18.4.8 TextureCoordinateGenerator</a> for recommended values.</span>
  </p>
</blockquote>
</EPM-HTML>"
4963;Parameter;"<EPM-HTML>
The parameters used as arguments by the function as specified by <em>Mode</em>.
<blockquote>
  <p>
    <span style=""font-size:smaller;color:red"">IFC2x4 CHANGE&nbsp; Made optional data type restricted to REAL.</span>
  </p>
</blockquote>
</EPM-HTML>"
4965;Vertices;"<EPM-HTML>
List of texture coordinate vertices that are applied to the corresponding points of the polyloop defining a face bound.
<blockquote>
  <p>
    <span style=""font-size:smaller"">NOTE&nbsp; The corresponding face bound may be an inner loop.</span>
  </p>
</blockquote>
</EPM-HTML>"
4966;AppliedTo;"<EPM-HTML>
Th face bound that defines the corresponding list of points along the bounding poly loop.
<blockquote>
  <p>
    <span style=""font-size:smaller"">NOTE&nbsp; The face bound may be an inner loop. In this case it defines an area to which no texturing shall be applied.</span>
  </p>
</blockquote>
</EPM-HTML>"
4968;Coordinates;The first coordinate[1] is the S, the second coordinate[2] is the T parameter value.
4970;Extent;The extent in the x and y direction of the text literal.
4971;BoxAlignment;The alignment of the text literal relative to its position.
4986;Name;"The name given to the light source in presentation.
"
4987;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.
"
4988;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). 
"
4989;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).
"
4992;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. 
"
4995;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.
"
4996;Radius;"Definition from IAI: 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.
"
4997;ConstantAttenuation;"Definition from ISO/CD 10303-46:1992: This real indicates the value of the attenuation in the lighting equation that is constant.
"
4998;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.
"
4999;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.
"
5001;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.
"
5002;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."
5654;V2;Second v parametric value.
5655;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.
5656;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.
5662;BasisSurface;"<EPM-HTML>
The surface to be bounded.
</EPM-HTML>"
5663;Boundaries;"<EPM-HTML>
The outer boundary of the surface.
</EPM-HTML>"
5664;ImplicitOuter;
5667;UDegree;"<EPM-HTML>
Algebraic degree of basis functions in <i>u</i>.
</EPM-HTML>"
5668;VDegree;"<EPM-HTML>
Algebraic degree of basis functions in <i>v</i>.
</EPM-HTML>"
5669;ControlPointsList;"<EPM-HTML>
This is a list of lists of control points.
</EPM-HTML>"
5671;SurfaceForm;"<EPM-HTML>
Indicator of special surface types.
</EPM-HTML>"
5672;UClosed;"<EPM-HTML>
Indication of whether the surface is closed in the <i>u</i> direction; this is for information only.
</EPM-HTML>"
5673;VClosed;"<EPM-HTML>
Indication of whether the surface is closed in the <i>v</i> direction; this is for information only.
</EPM-HTML>"
5674;SelfIntersect;"<EPM-HTML>
Flag to indicate whether, or not, surface is self-intersecting; this is for information only.
</EPM-HTML>"
5675;ControlPoints;"<EPM-HTML>
Array (two-dimensional) of control points defining surface geometry. This array is constructed from the control points list.
</EPM-HTML>"
5677;VUpper;"<EPM-HTML>
Upper index on control points in <i>v</i> direction.
</EPM-HTML>"
5678;UUpper;"<EPM-HTML>
Upper index on control points in <i>u</i> direction.
</EPM-HTML>"
5681;UMultiplicities;"<EPM-HTML>
The multiplicities of the knots in the <i>u</i> parameter direction.
</EPM-HTML>"
5682;VMultiplicities;"<EPM-HTML>
The multiplicities of the knots in the <i>v</i> parameter direction.
</EPM-HTML>"
5683;UKnots;"<EPM-HTML>
The list of the distinct knots in the <i>u</i> parameter direction.
</EPM-HTML>"
5684;VKnots;"<EPM-HTML>
The list of the distinct knots in the <i>v</i> parameter direction.
</EPM-HTML>"
1395;RiserHeight;"<EPM-HTML>
Vertical distance from tread to tread. The riser height is supposed to be equal for all stairs in a stair flight.
  <small><font color=""#ff0000"">
IFC2x4 CHANGE  The attribute has been deprecated it shall only be exposed with a NIL value. Use Pset_StairFlightCommon.RiserHeight instead.
  </font><small>
</EPM-HTML>"
1396;TreadLength;"<EPM-HTML>
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.
  <small><font color=""#ff0000"">
IFC2x4 CHANGE  The attribute has been deprecated it shall only be exposed with a NIL value. Use Pset_StairFlightCommon.TreadLength instead.
  </font><small>
</EPM-HTML>"
1397;PredefinedType;"<EPM-HTML>
Predefined generic type for a stair flight that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcStairFlightType</i> is assigned, providing its own <i>IfcStairFlightType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small></blockquote>
</EPM-HTML>"
1409;PredefinedType;"<EPM-HTML>
Predefined generic type for a ramp flight that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcRampFlightType</i> is assigned, providing its own <i>IfcRampFlightType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small></blockquote>
</EPM-HTML>"
1418;PredefinedType;"<EPM-HTML>
Predefined generic type for a curtain wall that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcCurtainWallType</i> is assigned, providing its own <i>IfcCurtainWallType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small></blockquote>
</EPM-HTML>"
1425;PredefinedType;"<EPM-HTML>
Predefined generic types for a railing that are specified in an enumeration. There may be a property set given for the predefined types.
<BLOCKQUOTE> <FONT SIZE=""-1"">NOTE: The use of the predefined type directly at the occurrence object level of <I>IfcRailing</I> is only permitted, if no type object <I>IfcRailingType</I> is assigned.</FONT></BLOCKQUOTE>
<BLOCKQUOTE> <FONT COLOR=""#FF0000"" SIZE=""-1"">IFC2x PLATFORM CHANGE: The attribute has been changed into an OPTIONAL attribute. </FONT></BLOCKQUOTE>
</EPM-HTML>"
1436;OverallHeight;"<EPM-HTML>Overall measure of the height, it reflects the Z Dimension of a bounding box, enclosing the <strike>body of the</strike> door opening. If omitted, the <i>OverallHeight</i> should be taken from the geometric representation of the <i>IfcOpening</i> in which the door is inserted. 
  <blockquote><small>
NOTE&nbsp; 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 <i>OverallHeight</i> shall still be given as the door opening height, and not as the total height of the door lining.</small></blockquote>
</EPM-HTML>"
1437;OverallWidth;"<EPM-HTML>Overall measure of the width, it reflects the X Dimension of a bounding box, enclosing the <strike>body of the</strike> door opening. If omitted, the <i>OverallWidth</i> should be taken from the geometric representation of the <i>IfcOpening</i> in which the door is inserted. 
  <blockquote> <small>
NOTE&nbsp; 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 <i>OverallWidth</i> shall still be given as the door opening width, and not as the total width of the door lining.</small></blockquote>
</EPM-HTML>"
1438;PredefinedType;"<EPM-HTML>
Predefined generic type for a door that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcDoorType</i> is assigned, providing its own <i>IfcDoorType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small></blockquote>
</EPM-HTML>"
1439;OperationType;"<EPM-HTML>
Type defining the general layout and operation of the door type in terms of the partitioning of panels and panel operations. 
<blockquote> 
  <small>NOTE The <i>OperationType</i> shall only be used, if no type object <i>IfcDoorType</i> is assigned, providing its own <i>IfcDoorType.OperationType</i>.
  </small>
<br>
  <small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font>
  </small>
</blockquote>
</EPM-HTML>"
1471;OverallHeight;"<EPM-HTML>Overall measure of the height, it reflects the Z Dimension of a bounding box, enclosing the <strike>body of the</strike> window opening. If omitted, the <i>OverallHeight</i> should be taken from the geometric representation of the <i>IfcOpening</i> in which the window is inserted. 
  <blockquote> <small>
NOTE&nbsp; 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 <i>OverallHeight</i> shall still be given as the window opening height, and not as the total height of the window lining.</small></blockquote>
</EPM-HTML>"
1472;OverallWidth;"<EPM-HTML>Overall measure of the width, it reflects the X Dimension of a bounding box, enclosing the <strike>body of the</strike> window opening. If omitted, the <i>OverallWidth</i> should be taken from the geometric representation of the <i>IfcOpening</i> in which the window is inserted. 
  <blockquote> <small>
NOTE&nbsp; 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 <i>OverallWidth</i> shall still be given as the window opening width, and not as the total width of the window lining.</small></blockquote>
</EPM-HTML>"
1473;PredefinedType;"<EPM-HTML>
Predefined generic type for a window that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcWindowType</i> is assigned, providing its own <i>IfcWindowType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small></blockquote>
</EPM-HTML>"
1474;PartitioningType;"<EPM-HTML>
Type defining the general layout of the window in terms of the partitioning of panels. 
<blockquote> 
  <small>NOTE The <i>PartitioningType</i> shall only be used, if no type object <i>IfcWindowType</i> is assigned, providing its own <i>IfcWindowType.PartitioningType</i>.
  </small>
<br>
  <small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font>
  </small>
</blockquote>
</EPM-HTML>"
1497;PredefinedType;"<EPM-HTML>
Predefined generic type for a plate that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcPlateType</i> is assigned, providing its own <i>IfcPlateType.PredefinedType</i>.</small>
<br>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added at the end of the entity definition.</font></small></blockquote>
</EPM-HTML>"
1508;PredefinedType;"<EPM-HTML>
Predefined generic type for a chimney that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcChimneyType</i> is assigned, providing its own <i>IfcChimneyType.PredefinedType</i>.</small>
</blockquote>
</EPM-HTML>"
1515;PredefinedType;
1527;PredefinedType;Predefined types to define the particular type of the covering. There may be property set definitions available for each predefined type.
1528;CoversSpaces;"<EPM-HTML>
Reference to the objectified relationship that handles the relationship of the covering to the covered space.
</EPM-HTML>"
1529;CoversElements;"<EPM-HTML>
Reference to the objectified relationship that handles the relationship of the covering to the covered element.
<blockquote><small><font color=""#ff0000"">IFC2x4 CHANGE  Renamed into <i>CoversElements</i> for consistency.
</font></small></blockquote>
</EPM-HTML>
"
1544;RelatingBuildingElement;"<EPM-HTML>
Relationship to the building element that is covered. 
<blockquote>
  <small><font color=""#ff0000"">
IFC2x4 CHANGE: The attribute type has been changed from <i>IfcElement</i> to <i>IfcBuildingElement</i>.
  </font><small>
</blockquote>
</EPM-HTML>"
1545;RelatedCoverings;"Relationship to the set of coverings at this element.
"
1547;PredefinedType;"<EPM-HTML>
Predefined generic type for a shading device that is specified in an enumeration. There may be a property set given specificly for the predefined types.
<blockquote> <small>NOTE The <i>PredefinedType</i> shall only be used, if no type object <i>IfcShadingDeviceType</i> is assigned, providing its own <i>IfcShadingDeviceType.PredefinedType</i>.</small>
</blockquote>
</EPM-HTML>"
1557;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a slab element from which the type required may be set.
</EPM-HTML>"
1560;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a wall element from which the type required may be set.
</EPM-HTML>"
1563;PredefinedType;Identifies the predefined types of a stair flight element from which the type required may be set.
1566;PredefinedType;Identifies the predefined types of a railing element from which the type required may be set.
1569;PredefinedType;Identifies the predefined types of a ramp flight element from which the type required may be set.
1572;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a beam element from which the type required may be set.
</EPM-HTML>"
1575;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a column element from which the type required may be set.
</EPM-HTML>"
1578;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a linear structural member element from which the type required may be set.
</EPM-HTML>"
1581;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a curtain wall element from which the type required may be set.
</EPM-HTML>"
1584;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a planar member element from which the type required may be set.
</EPM-HTML>"
1587;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a stair element from which the type required may be set.
</EPM-HTML>"
1590;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a ramp element from which the type required may be set.
</EPM-HTML>"
1593;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a roof element from which the type required may be set.
</EPM-HTML>"
1596;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a chimney element from which the type required may be set.
</EPM-HTML>"
1599;PredefinedType;"<EPM-HTML>
Predefined types to define the particular type of an building element proxy. There may be property set definitions available for each predefined or user defined type.
</EPM-HTML>"
1601;PredefinedType;"<EPM-HTML>
Predefined types to define the particular type of the covering. There may be property set definitions available for each predefined type.
</EPM-HTML>"
1604;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a door element from which the type required may be set.
</EPM-HTML>"
1605;OperationType;"<EPM-HTML>
Type defining the general layout and operation of the door type in terms of the partitioning of panels and panel operations. 
</EPM-HTML>"
1607;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a window element from which the type required may be set.
</EPM-HTML>"
1608;PartitioningType;"<EPM-HTML>
Type defining the general layout of the window type in terms of the partitioning of panels. 
</EPM-HTML>"
1610;PredefinedType;"<EPM-HTML>
Identifies the predefined types of a shading device element from which the type required may be set.
</EPM-HTML>"
1612;PredefinedType;"<EPM-HTML>
Predefined types of distribution systems.
</EPM-HTML>"
1622;Identification;"<EPM-HTML>A unique identification assigned to an asset that enables its differentiation from other assets.
<p><b>NOTE:</b> 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.</p>
</EPM-HTML>"
1623;OriginalValue;<EPM-HTML>The cost value of the asset at the time of purchase.</EPM-HTML>
1624;CurrentValue;<EPM-HTML>The current cost value of the asset.</EPM-HTML>
1625;TotalReplacementCost;<EPM-HTML>The total cost of replacement of the asset.</EPM-HTML>
1626;Owner;<EPM-HTML>The name of the person or organization that 'owns' the asset.</EPM-HTML>
1627;User;<EPM-HTML>The name of the person or organization that 'uses' the asset.</EPM-HTML>
1628;ResponsiblePerson;"<EPM-HTML>The person designated to be responsible for the asset.
<p><b>NOTE:</b> In some regulations (for example, UK Health and Safety at Work Act, Electricity at Work Regulations), 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.</p>
</EPM-HTML>"
1629;IncorporationDate;"<EPM-HTML> 
The date on which an asset was incorporated into the works, installed, constructed, erected or completed.
<p><b>NOTE:</b> This is the date on which an asset is considered to start depreciating.</p>
<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE Type changed from IfcDateTimeSelect. 
    </font> 
  </small> 
</blockquote> 
</EPM-HTML> 
"
1630;DepreciatedValue;<EPM-HTML>The current value of an asset within the accounting rules and procedures of an organization.</EPM-HTML>
1632;PredefinedType;"<EPM-HTML>A list of the types of inventories from which that required may be selected.
<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE Attribute made optional. 
    </font> 
  </small> 
</blockquote> 
</EPM-HTML>
"
1633;Jurisdiction;<EPM-HTML>The organizational unit to which the inventory is applicable.</EPM-HTML>
1634;ResponsiblePersons;<EPM-HTML>Persons who are responsible for the inventory.</EPM-HTML>
1635;LastUpdateDate;"<EPM-HTML> 
<p>The date on which the last update of the inventory was carried out.</p>
<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE Type changed from IfcDateTimeSelect. 
    </font> 
  </small> 
</blockquote> 
</EPM-HTML> 
"
1636;CurrentValue;<EPM-HTML>An estimate of the current cost value of the inventory.</EPM-HTML>
1637;OriginalValue;<EPM-HTML>An estimate of the original cost value of the inventory.</EPM-HTML>
1645;PredefinedType;"<EPM-HTML>Predefined occupant types from which that required may be set.

<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE Attribute made optional. 
    </font> 
  </small> 
</blockquote> 

</EPM-HTML>"
1658;PredefinedType;
1667;PredefinedType;
1681;PredefinedType;
1684;AssemblyPlace;<EPM-HTML><p>A designation of where the assembly is intended to take place. A selection of alternatives s provided in an enumerated list.</p></EPM-HTML>
1685;PredefinedType;
1689;OperationType;"<EPM-HTML>
Type defining the general layout and operation of the door style.
<br>
</EPM-HTML>"
1690;ConstructionType;"<EPM-HTML>
Type defining the basic construction and material type of the door.
<br>
</EPM-HTML>"
1691;ParameterTakesPrecedence;"<EPM-HTML>
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.
<br>
</EPM-HTML>"
1692;Sizeable;"<EPM-HTML>
The Boolean indicates, whether the attached <i>IfcMappedRepresentation</i> (if given) can be sized (using scale factor of transformation), or not (FALSE). If not, the <i>IfcMappedRepresentation</i> should be <i>IfcShapeRepresentation</i> of the <i>IfcDoor</i> (using <i>IfcMappedItem</i> as the <i>Item</i>) with the scale factor = 1.
<br>
</EPM-HTML>"
1723;ConstructionType;Type defining the basic construction and material type of the window.
1724;OperationType;Type defining the general layout and operation of the window style.
1725;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.
1726;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.
1749;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).
1750;LiningThickness;Thickness (width in plane parallel to door leaf) of the door lining.
1751;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).
1752;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.
1753;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.
1754;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.
1755;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.
1756;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.
1757;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.
1758;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.
1759;ShapeAspectStyle;"<EPM-HTML>
Pointer to the shape aspect, if given. The shape aspect reflects the part of the door shape, which represents the door lining.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE The attribute is deprecated and shall no longer be used, i.e. the value shall be NIL ($).
</font><small></blockquote>
</EPM-HTML>"
1760;LiningToPanelOffsetX;"<EPM-HTML>
Offset between the lining and the window panel measured along the x-axis of the local placement.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE: New attribute added at the end of the entity definition.
</font></small></blockquote>
</EPM-HTML>"
1761;LiningToPanelOffsetY;"<EPM-HTML>
Offset between the lining and the door panel measured along the y-axis of the local placement.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE: New attribute added at the end of the entity definition.
</font></small></blockquote>
</EPM-HTML>"
1768;PanelDepth;"<EPM-HTML>
Depth of the door panel, measured perpendicular to the plane of the door leaf.
</EPM-HTML>"
1769;PanelOperation;"<EPM-HTML>
The <i>PanelOperation</i> defines the way of operation of that panel. The <i>PanelOperation</i> of the door panel has to correspond with the <i>OperationType</i> of the <i>IfcDoorStyle</i> by which it is referenced.
</EPM-HTML>"
1770;PanelWidth;"<EPM-HTML>
Width of this panel, given as ratio relative to the total clear opening width of the door. If omited, it defaults to 1. A value has to be provided for all doors with <i>OperationType</i>'s at <i>IfcDoorStyle</i> defining a door with more then one panel.
</EPM-HTML>"
1771;PanelPosition;"<EPM-HTML>
Position of this panel within the door. The <i>PanelPosition</i> of the door panel has to correspond with the <i>OperationType</i> of the <i>IfcDoorStyle</i> by which it is referenced.
</EPM-HTML>"
1772;ShapeAspectStyle;"<EPM-HTML>
Pointer to the shape aspect, if given. The shape aspect reflects the part of the door shape, which represents the door panel.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE The attribute is deprecated and shall no longer be used, i.e. the value shall be NIL ($).
</font><small></blockquote>
</EPM-HTML>"
1790;OperationType;"Types of window panel operations. Also used to assign standard symbolic presentations according to national building standards.
"
1791;PanelPosition;Position of this panel within the overall window style.
1792;FrameDepth;Depth of panel frame, measured from front face to back face horizontally (i.e. perpendicular to the window (elevation) plane.
1793;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.
1794;ShapeAspectStyle;"<EPM-HTML>
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.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE The attribute is deprecated and shall no longer be used, i.e. the value shall be NIL ($).
</font><small></blockquote>
</EPM-HTML>"
1818;LiningDepth;Depth of the window lining (dimension measured perpendicular to window elevation plane).
1819;LiningThickness;Thickness of the window lining (measured parallel to the window elevation plane).
1820;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.
1821;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.
1822;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.
1823;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.
1824;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.
1825;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.
1826;ShapeAspectStyle;"<EPM-HTML>
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.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE The attribute is deprecated and shall no longer be used, i.e. the value shall be NIL ($).
</font><small></blockquote>
</EPM-HTML>"
1827;LiningOffset;"<EPM-HTML>
Offset of the window lining. The offset is given as distance along the y axis of the local placement (perpendicular to the window plane).
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE: New attribute added at the end of the entity definition.
</font></small></blockquote>
</EPM-HTML>"
1828;LiningToPanelOffsetX;"<EPM-HTML>
Offset between the lining and the window panel measured along the x-axis of the local placement. Should be smaller or equal to the <i>LiningThickness</i>.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE: New attribute added at the end of the entity definition.
</font></small></blockquote>
</EPM-HTML>"
1829;LiningToPanelOffsetY;"<EPM-HTML>
Offset between the lining and the window panel measured along the y-axis of the local placement. Should be smaller or equal to the <i>IfcWindowPanelProperties.PanelThickness</i>.
<blockquote><small><font color=""#ff0000"">
IFC2x4 CHANGE: New attribute added at the end of the entity definition.
</font></small></blockquote>
</EPM-HTML>"
1835;OperationType;"Types of permeable covering operations. Also used to assign standard symbolic presentations according to national building standards.
"
1836;PanelPosition;Position of this permeable covering panel within the overall window or door type.
1837;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.
1838;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.
1839;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.
1848;PredefinedType;
1863;PredefinedType;
1875;PredefinedType;
1887;PredefinedType;
1914;PredefinedType;
1927;PredefinedType;
1942;PredefinedType;<EPM-HTML><p>Identifies the predefined types of sensor from which the type required may be set.</p></EPM-HTML>
1945;PredefinedType;<EPM-HTML><p>Identifies the predefined types of controller from which the type required may be set.</p></EPM-HTML>
1948;PredefinedType;<EPM-HTML><p>Identifies the predefined types of actuator from which the type required may be set.</p></EPM-HTML>
1951;PredefinedType;<EPM-HTML><p>Identifies the predefined types of flow instrument from which the type required may be set.</p></EPM-HTML>
1954;PredefinedType;<EPM-HTML><p>Identifies the predefined types of alarm from which the type required may be set.</p></EPM-HTML>
1957;PredefinedType;<EPM-HTML><p>Identifies the predefined types of unitary control element from which the type required may be set.</p></EPM-HTML>
1963;AssignedStructuralActivity;Inverse relationship to all structural activities (i.e. to actions or reactions) which are assigned to this structural member.
1967;ConnectedBy;Inverse relationship to all structural connections (i.e. to supports or connecting elements) which are defined for this structural member.
1970;PredefinedType;Type of member with respect to its load carrying behavior in this analysis idealization.
1971;Axis;"<EPM-HTML>

Direction which is used in the definition of the local z axis.  <i>Axis</i> is specified relative to the so-called global coordinate system, i.e. the <i>SELF\IfcProduct.ObjectPlacement</i>.

<blockquote><font size=""-1"">NOTE&nbsp; It is desirable and usually possible that many instances of <i>IfcStructuralCurveConnection</i> and <i>IfcStructuralCurveMember</i> share a common instance of <i>IfcDirection</i> as their <i>Axis</i> attribute.</font></blockquote>

</EPM-HTML>"
1984;PredefinedType;Type of member with respect to its load carrying behavior in this analysis idealization.
1985;Thickness;Defines the typically understood thickness of the structural surface member, measured normal to its reference surface.
1996;RelatingStructuralMember;Reference to an instance of IfcStructuralMember (or its subclasses) which is connected to the specified structural connection.
1997;RelatedStructuralConnection;Reference to an instance of IfcStructuralConnection (or its subclasses) which is connected to the specified structural member.
1998;AppliedCondition;"Conditions which define the connections properties.  Connection conditions are often called &quot;release&quot; but are not only used to define mechanisms like hinges but also rigid, elastic, and other conditions."
1999;AdditionalConditions;Describes additional connection properties.
2000;SupportedLength;Defines the 'supported length' of this structural connection. See Fig. for more detail.
2001;ConditionCoordinateSystem;"<EPM-HTML>

Defines a coordinate system used for the description of the connection properties in <i>ConnectionCondition</i> relative to the local coordinate system of <i>RelatingStructuralMember</i>.  If left unspecified, the placement <i>IfcAxis2Placement3D</i>((x,y,z), ?, ?) is implied with x,y,z being the local member coordinates where the connection is made and the default axes directions being in parallel with the local axes of <i>RelatingStructuralMember</i>.

</EPM-HTML>"
2003;RelatingElement;Reference to a structural item or element to which the specified activity is applied.
2004;RelatedStructuralActivity;Reference to a structural activity which is acting upon the specified structural item or element.
2009;PredefinedType;Defines the type of the structural analysis model.
2010;OrientationOf2DPlane;"<EPM-HTML>

If the selected model type (<i>PredefinedType</i>) describes a 2D system, the orientation defines
the analysis plane (P[1], P[2]) and the normal to the analysis plane (P[3]).  This is needed because
structural items and activities are always defined in three-dimensional space even if they are
meant to be analysed in a two-dimensional manner.

<ul>
<li>In case of predefined type IN_PLANE_LOADING_2D, the analysis is to be performed within the
projection into the P[1], P[2] plane.</li>
<li>In case of predefined type OUT_PLANE_LOADING_2D, only the P[3] component of loads and their
effects is meant to be analyzed.  This is used for beam grids and for typical slab analyses.</li>
<li>In case of predefined type LOADING_3D, <i>OrientationOf2DPlane</i> shall be omitted.</li>
</ul>

</EPM-HTML>"
2011;LoadedBy;References to all load groups to be analyzed.
2012;HasResults;References to all result groups available for this structural analysis model.
2013;SharedPlacement;"<EPM-HTML>

Object placement which shall be common to all items and activities which are grouped into this instance of <i>IfcStructuralAnalysisModel</i>.  This placement establishes a coordinate system which is referred to as 'global coordinate system' in use definitions of various classes of structural items and activities.

<blockquote><font size=""-1"">NOTE&nbsp; Most commonly, but not necessarily, the <i>SharedPlacement</i> is an <i>IfcLocalPlacement</i> whose z axis is parallel with the z axis of the <i>IfcProject</i>'s world coordinate system and directed like the WCS z axis (i.e. pointing &quot;upwards&quot;) or directed against the WCS z axis (i.e. points &quot;downwards&quot;).</font></blockquote>

<blockquote><font size=""-1"">NOTE&nbsp; Per informal proposition, this attribute is <b>not optional</b> as soon as at least one <i>IfcStructuralItem</i> is grouped into the instance of <i>IfcStructuralAnalysisModel</i>.</font></blockquote>

</EPM-HTML>"
2023;PredefinedType;"Selects a predefined type for the load group.  It can be differentiated between load groups, load cases, load combinations, or userdefined grouping levels.
"
2024;ActionType;Type of actions in the group. Normally needed if 'PredefinedType' specifies a LOAD_CASE.
2025;ActionSource;Source of actions in the group. Normally needed if 'PredefinedType' specifies a LOAD_CASE.
2026;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.
2027;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.
2028;SourceOfResultGroup;Results which were computed using this load group.
2029;LoadGroupFor;Analysis models in which this load group is used.
2032;TheoryType;Specifies the analysis theory used to obtain the respective results.
2033;ResultForLoadGroup;Reference to an instance of IfcStructuralLoadGroup for which this instance represents the result.
2034;IsLinear;This value allows to easily recognize whether a linear analysis has been applied (allowing the superposition of analysis results).
2035;ResultGroupFor;Reference to an instance of IfcStructuralAnalysisModel for which this instance captures a result.
2045;SelfWeightCoefficients;"<EPM-HTML>

The self weight coefficients specify ratios at which loads due to weight of members shall be included in the load case.  These loads are not explicitly modeled as instances of <i>IfcStructuralAction</i>.  Instead they shall be calculated according to geometry, section, and material of each member.

<p>The three components of the self weight vector correspond with the x,y,z directions of the so-called global coordinates, i.e. the directions of the shared <i>ObjectPlacement</i> of all items in an <i>IfcStructuralAnalysisModel</i>.  For example, if the object placement defines a z axis which is upright like the <i>IfcProject</i>'s world coordinate system, then the self weight coefficients would typically be [0.,0.,-1.] in a load case of dead loads with self weight.</p>

<p>The overall coefficient in the inherited attribute <i>Coefficient</i> shall not be applied to <i>SelfWeightCoefficients</i> of the same instance of <i>IfcStructuralLoadCase</i>.  It only applies to actions and load groups which are grouped below the load case, not to the load case's computed self weight.

</EPM-HTML>"
2046;PredefinedType;"<EPM-HTML>

An <i>IfcStructuralLoadCase</i> is a load group of type LOAD_CASE.

</EPM-HTML>"
2090;AppliedLoad;"<EPM-HTML>

Load or result resource object which defines the load type, direction, and load values.

<p>In case of activities which are variably distributed over curves or surfaces, <i>IfcStructuralLoadConfiguration</i> is used which provides a list of load samples and their locations within the load distribution, measured in local coordinates of the curve or surface on which this activity acts.  The contents of this load or result distribution may be further restricted by definitions at subtypes of <i>IfcStructuralActivity</i>.</p>

</EPM-HTML>"
2091;GlobalOrLocal;"<EPM-HTML>

Indicates whether the load directions refer to the global coordinate system (global to
the analysis model, i.e. as established by <i>IfcStructuralAnalysisModel.SharedPlacement</i>)
or to the local coordinate system (local to the activity or connected item, as established by
an explicit or implied representation and its parameter space).

<blockquote><font size=""-1"">NOTE, the informal definition of
<i>IfcRepresentationResource.IfcGlobalOrLocalEnum</i> doe s not distinguish between
&quot;global coordinate system&quot; and &quot;world coordinate system&quot;.
On the other hand, this distinction is necessary in the <i>IfcStructuralAnalysisDomain</i>
where the shared &quot;global&quot; coordinate system of an analysis model may very well
not be the same as the project-wide world coordinate system.</font></blockquote>

<blockquote><font size=""-1"">In the scope of <i>IfcStructuralActivity.GlobalOrLocal</i>,
the meaning of GLOBAL_COORDS is therefore not to be taken as world coordinate system
but as the analysis model specific shared coordinate system.  In contrast, LOCAL_COORDS
is to be taken as coordinates which are local to individual structural items and activities,
as established by subclass-specific geometry use definitions.</font></blockquote>

</EPM-HTML>"
2092;AssignedToStructuralItem;"<EPM-HTML>

Reference to the <i>IfcRelConnectsStructuralActivity</i> relationship by which activities are connected with structural items.

</EPM-HTML>"
2097;DestabilizingLoad;Indicates if this action may cause a stability problem. If it is 'FALSE', no further investigations regarding stability problems are necessary.
2101;ProjectedOrTrue;Defines whether load values are given per true length of the curve on which they act, or per length of the projection of the curve in load direction.  The latter is only applicable to loads which act in global coordinate directions.
2102;PredefinedType;Type of action according to its distribution of load values.
2107;PredefinedType;The load is uniformly distributed over the curve.
2123;ProjectedOrTrue;Defines whether load values are given per true lengths of the surface on which they act, or per lengths of the projection of the surface in load direction.  The latter is only applicable to loads which act in global coordinate directions.
2124;PredefinedType;Type of action according to its distribution of load values.
2128;PredefinedType;The load is uniformly distributed over the surface.
2142;PredefinedType;Type of reaction according to its distribution of load values.
2146;PredefinedType;Type of reaction according to its distribution of load values.
2149;ConnectionConstraint;The connection constraint explicitly states the eccentricity between a structural member and a structural connection by means of two topological objects (vertex and vertex, or edge and edge, or face and face).
2154;AppliedCondition;Optional boundary conditions which define support conditions of this connection object, given in local coordinate directions of the connection object.  If left unspecified, the connection object is assumed to have no supports besides being connected with members.
2155;ConnectsStructuralMembers;References to the IfcRelConnectsStructuralMembers relationship by which structural members can be associated to structural connections.
2157;Axis;"<EPM-HTML>

Direction which is used in the definition of the local z axis.  <i>Axis</i> is specified relative to the so-called global coordinate system, i.e. the <i>SELF\IfcProduct.ObjectPlacement</i>.

<blockquote><font size=""-1"">NOTE&nbsp; It is desirable and usually possible that many instances of <i>IfcStructuralCurveConnection</i> and <i>IfcStructuralCurveMember</i> share a common instance of <i>IfcDirection</i> as their <i>Axis</i> attribute.</font></blockquote>

</EPM-HTML>"
2159;ConditionCoordinateSystem;"<EPM-HTML>

Defines a coordinate system used for the description of the support condition properties in <i>SELF\IfcStructuralConnection.SupportCondition</i>, specified relative to the global coordinate system (global to the structural analysis model) established by <i>SELF.\IfcProduct.ObjectPlacement</i>.  If left unspecified, the placement <i>IfcAxis2Placement3D</i>((x,y,z), ?, ?) is implied with x,y,z being the coordinates of the reference point of this <i>IfcStructuralPointConnection</i> and the default axes directions being in parallel with the global axes.

</EPM-HTML>"
2168;CoordinateSpaceDimension;"<EPM-HTML>The integer dimension count of the coordinate space modeled in a geometric representation context.
<br>
<EPM-HTML>"
2169;Precision;"<EPM-HTML>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.
</EPM-HTML>"
2170;WorldCoordinateSystem;"<EPM-HTML>
Establishment of the engineering coordinate system (often referred to as the world coordinate system in CAD) for all representation contexts used by the project. 
<blockquote><small> 
Note&nbsp; 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.).
</small> </blockquote>
</EPM-HTML>"
2171;TrueNorth;"<EPM-HTML>
Direction of the true north, or geographic northing direction, relative to the underlying project coordinate system. It is given by a 2 dimensional direction within the xy-plane of the project coordinate system. If not resent, it defaults to 0. 1. - i.e. the positive Y axis of the project coordinate system equals the geographic northing direction.
<br>
</EPM-HTML>"
2172;HasSubContexts;"<EPM-HTML>
The set of <i>IfcGeometricRepresentationSubContexts</i> that refer to this <i>IfcGeometricRepresentationContext</i>.
<blockquote><small>
  <font color=""#FF0000"">IFC2x Edition 3 CHANGE&nbsp; New inverse attribute.</font>
</small></blockquote>
</EPM-HTML>"
2176;ContextIdentifier;The optional identifier of the representation context as used within a project.
2177;ContextType;The description of the type of a representation context. The supported values for context type are to be specified by implementers agreements.
2178;RepresentationsInContext;All shape representations that are defined in the same representation context.
2182;ContextOfItems;Definition of the representation context for which the different subtypes of representation are valid.
2183;RepresentationIdentifier;The optional identifier of the representation as used within a project.
2184;RepresentationType;"<EPM-HTML>
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 <i>IfcShapeRepresentation</i> and <i>IfcTopologyRepresentation</i>.<br>
The supported values for context type are to be specified by implementers agreements.
</EPM-HTML>
"
2185;Items;Set of geometric representation items that are defined for this representation.
2186;RepresentationMap;"<EPM-HTML>
Use of the representation within an <i>IfcRepresentationMap</i>. If used, this <i>IfcRepresentation</i> may be assigned to many representations as one of its <i>Items</i> using an <i>IfcMappedItem</i>. Using <i>IfcRepresentationMap</i> is the way to share one representation (often of type <i>IfcShapeRepresentation</i>) by many products.  
<blockquote><small><font color=""#ff0000"">
IFC2x Edition 3 CHANGE&nbsp; The inverse attribute <i>LayerAssignments</i> has been added.
</font></small></blockquote>
</EPM-HTML>"
2187;LayerAssignments;"<EPM-HTML>Assignment of the whole representation to a single or multiple layer(s). The <i>LayerAssigments</i> can be overridden by <i>LayerAssigments</i> of the <i>IfcRepresentationItem</i>'s within the list of <i>Items</i>.
<blockquote><small>NOTE&nbsp; Implementation agreements can restrict the maximum number of layer assignments to 1.</small><br>
<small><font color=""#ff0000"">IFC2x Edition 3 CHANGE&nbsp; The inverse attribute <i>LayerAssignments</i> has been added.
</font></small></blockquote>
</EPM-HTML>"
2188;OfProductRepresentation;"<EPM-HTML>
Reference to the product representations to which this individual representation applies. In most cases it is the reference to one or many product shapes, to which this shape representation is applicable.
<blockquote><small>
<font color=""#ff0000"">IFC2x4 CHANGE Inverse relationship cardinality relaxed to be 0:N.
</small></blockquote>
</EPM-HTML>"
2196;OfShapeAspect;Reference to the shape aspect, for which it is the shape representation.
2208;ShapeRepresentations;"<EPM-HTML>List of <strike>shape</strike> 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.
<blockquote><small><font color=""#FF0000"">IFC2x Edition 3 CHANGE&nbsp; The data type has been changed from <i>IfcShapeRepresentation</i> to <i>IfcShapeModel</i> with upward compatibility </font></small></blockquote>
</EPM-HTML>"
2209;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."
2210;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.
2211;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.
---"
2212;PartOfProductDefinitionShape;Reference to the product definition shape of which this class is an aspect.
2214;ShapeOfProduct;"<EPM-HTML>
The <i>IfcProductDefinitionShape</i> shall be used to provide a representation for a single instance of <i>IfcProduct</i>.
<blockquote><small>
  <font color=""#FF0000"">IFC2x3 CHANGE New inverse attribute.</font><br>
<font color=""#ff0000"">IFC2x4 CHANGE Inverse relationship cardinality relaxed to be 1:N.
</small></blockquote>
</EPM-HTML>"
2215;HasShapeAspects;Reference to the shape aspect that represents part of the shape or its feature distinctively.
2220;Name;The word or group of words by which the product representation is known.
2221;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.
2222;Representations;Contained list of representations (including shape representations). Each member defines a valid representation of a particular type within a particular representation context.
2224;RepresentedMaterial;Reference to the material to which the representation applies.
2227;ParentContext;Parent context from which the sub context derives its world coordinate system, precision, space coordinate dimension and true north.
2228;TargetScale;"<EPM-HTML>
The target <font color=""#ff0000"">plot</font> scale of the representation 
to which this representation context applies.
<blockquote> <font size=""-1""> 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.<br>
If multiple instances of <i>IfcGeometricRepresentationSubContext</i>
are given having the same <i>TargetView</i> value, the target plot scale 
applies up to the next smaller scale, or up to unlimited small scale.
  <br>
  <br>
Note: Scale 1:100 (given as 0.01 within <i>TargetScale</i>)
is bigger then 1:200 (given as 0.005 within <i>TargetScale</i>).
  </font></blockquote>
</EPM-HTML>"
2229;TargetView;Target view of the representation to which this representation context applies.
2230;UserDefinedTargetView;User defined target view, this attribute value shall be given, if the TargetView attribute is set to USERDEFINED.
2231;WorldCoordinateSystem;
2232;CoordinateSpaceDimension;
2233;TrueNorth;
2234;Precision;
2260;Name;"<EPM-HTML>Name by which the coordinate reference system is identified.
<blockquote><small>Note&nbsp; The name shall be taken from the list recognized by the European Petroleum Survey Group EPSG.
</small></blockquote>
</EPM-HTML>
"
2261;Description;"<EPM-HTML>Informal description of this coordinate reference system.<br></EPM-HTML>
"
2262;GeodeticDatum;"<EPM-HTML>
Name by which this datum is identified. The geodetic datum is associated with the coordinate reference system and indicates the shape and size of the rotation ellipsoid and this ellipsoid's connection and orientation to the actual globe/earth. Examples for geodetic datums include:
<ul>
  <li>ED50</li>
  <li>EUREF89</li>
  <li>WSG84</li>
<ul>
</EPM-HTML>
"
2263;VerticalDatum;"<EPM-HTML>Name by which the vertical datum is identified. The vertical datum is associated with the height axis of the coordinate reference system and indicates the reference plane and fundamental point defining the origin of a height system. Examples for vertical datums include:
<UL>
  <LI>height above mean sea level at Dover in 1952</LI>
  <LI>other sea levels</LI>
<UL>
</EPM-HTML>"
2265;MapProjection;"<EPM-HTML>Name by which the map projection is identified.
<UL>
  <LI>UTM</LI>
  <LI>Gaus-Krueger</LI>
<UL>
</EPM-HTML>"
2266;MapZone;"<EPM-HTML>Name by which the map zone, relating to the <I>MapProjection</I>, is identified. Examples are
<UL>
  <LI>for UTM, the zone number, like 32 for UTM32</LI>
  <LI>for Gaus-Krueger, the zones of longitudinal width, like 3'</LI>
<UL>
</EPM-HTML>"
2267;MapUnit;"<EPM-HTML>Unit of the coordinate axes composing the map coordinate system.
<blockquote><small>NOTE&nbsp; Only length measures are in scope and all two or three axes of the map coordinate system shall have the same length unit.</small>
</Bblockquote>
</EPM-HTML>"
2271;SourceCRS;Source coordinate reference system for the operation.
2272;TargetCRS;Target coordinate reference system for the operation.
2274;Eastings;"<EPM-HTML>Specifies the location along the easting of the coordinate system of the target map coordinate reference system.
<blockquote><small>NOTE&nbsp; for right-handed Cartesian coordinate systems this would establish the location along the x axis</small></blockquote>
</EPM-HTML>"
2275;Northings;"<EPM-HTML>Specifies the location along the northing of the coordinate system of the target map coordinate reference system.
<blockquote><small>NOTE&nbsp; for right-handed Cartesian coordinate systems this would establish the location along the y axis</small></blockquote>
</EPM-HTML>"
2276;OrthogonalHeight;"<EPM-HTML>Orthogonal height relativ to the vertical datum specified.
<blockquote><small>NOTE&nbsp; for right-handed Cartesian coordinate systems this would establish the location along the z axis</small></blockquote>
<EPM-HTML>"
2277;XAxisAbscissa;"<EPM-HTML> Specifies the value along the easing axis of the end point of a vector indicating the position of the local x axis of the engineering coordinate reference system.
<blockquote><small>NOTE&nbsp; for right-handed Cartesian coordinate systems this would establish the location along the x axis<br>
NOTE&nbsp; together with the <i>XAxisOrdinate</i> it provides the direction of the local x axis within the horizontal plane of the map coordinate system</small></blockquote>
</EPM-HTML>"
2278;XAxisOrdinate;"<EPM-HTML> Specifies the value along the northing axis of the end point of a vector indicating the position of the local x axis of the engineering coordinate reference system.
<blockquote><small>NOTE&nbsp; for right-handed Cartesian coordinate systems this would establish the location along the y axis<br>
NOTE&nbsp; together with the <I>XAxisAbscissa</I> it provides the direction of the local x axis within the horizontal plane of the map coordinate system</small></blockquote>
</EPM-HTML>"
2279;Scale;"<EPM-HTML>Scale to be used, when the units of the CRS are not identical to the units of the engineering coordinate system. If omited, the value of 1.0 is assumed.
</EPM-HTML>"
2287;Name;Optionally defines a name for this load.
2289;Values;List of load or result values.
2290;Locations;Locations of the load samples or result samples, given within the local coordinate system defined by the instance which uses this resource object.  Each item in the list of locations pertains to the values list item at the same list index.  This attribute is optional for configurations in which the locations are implicitly known from higher-level definitions.
2301;ForceX;Force value in x-direction.
2302;ForceY;Force value in y-direction.
2303;ForceZ;Force value in z-direction.
2304;MomentX;Moment about the x-axis.
2305;MomentY;Moment about the y-axis.
2306;MomentZ;Moment about the z-axis.
2308;WarpingMoment;The warping moment at the point load.
2310;LinearForceX;Linear force value in x-direction.
2311;LinearForceY;Linear force value in y-direction.
2312;LinearForceZ;Linear force value in z-direction.
2313;LinearMomentX;Linear moment about the x-axis.
2314;LinearMomentY;Linear moment about the y-axis.
2315;LinearMomentZ;Linear moment about the z-axis.
2317;PlanarForceX;Planar force value in x-direction.
2318;PlanarForceY;Planar force value in y-direction.
2319;PlanarForceZ;Planar force value in z-direction.
2322;DisplacementX;Displacement in x-direction.
2323;DisplacementY;Displacement in y-direction.
2324;DisplacementZ;Displacement in z-direction.
2325;RotationalDisplacementRX;Rotation about the x-axis.
2326;RotationalDisplacementRY;Rotation about the y-axis.
2327;RotationalDisplacementRZ;Rotation about the z-axis.
2329;Distortion;The distortion curvature (warping, i.e. a cross-sectional deplanation) given to the displacement load.
2331;DeltaTConstant;"<EPM-HTML>

Temperature change which affects the complete section of the structural member, or the uniform portion of a non-uniform temperature change.

<blockquote><small>A positive value describes an increase in temperature.  I.e. a positive constant temperature change causes elongation of a member, or compression in the member if there are respective restraints.</small></blockquote>

</EPM-HTML>"
2332;DeltaTY;"<EPM-HTML>

Non-uniform temperature change, specified as the difference of the temperature change at the outer fibre of the positive y direction minus the temperature change at the outer fibre of the negative y direction of the analysis member.

<blockquote><small>I.e. a positive non-uniform temperature change in y induces a negative curvature of the member about z, or a positive bending moment about z if there are respective restraints.  y and z are local member axes.</small></blockquote>

</EPM-HTML>"
2333;DeltaTZ;"<EPM-HTML>

Non-uniform temperature change, specified as the difference of the temperature change at the outer fibre of the positive z direction minus the temperature change at the outer fibre of the negative z direction of the analysis member.

<blockquote><small>I.e. a positive non-uniform temperature change in z induces a positive curvature of the member about y, or a negative bending moment about y if there are respective restraints.  y and z are local member axes.</small></blockquote>

</EPM-HTML>"
2335;SurfaceReinforcement1;Reinforcement at the face of the member which is located at the side of the positive local z direction of the surface member.  Specified as area per length, e.g. square metre per metre (hence length measure, e.g. metre).  The reinforcement area may be specified for two or three directions of reinforcement bars.
2336;SurfaceReinforcement2;Reinforcement at the face of the member which is located at the side of the negative local z direction of the surface member.  Specified as area per length, e.g. square metre per metre (hence length measure, e.g. metre).  The reinforcement area may be specified for two or three directions of reinforcement bars.
2337;ShearReinforcement;Shear reinforcement.  Specified as area per area, e.g. square metre per square metre (hence ratio measure, i.e. unitless).
2346;Name;Optionally defines a name for this boundary condition.
2349;TranslationalStiffnessX;Translational stiffness value in x-direction of the coordinate system defined by the instance which uses this resource object.
2350;TranslationalStiffnessY;Translational stiffness value in y-direction of the coordinate system defined by the instance which uses this resource object.
2351;TranslationalStiffnessZ;Translational stiffness value in z-direction of the coordinate system defined by the instance which uses this resource object.
2352;RotationalStiffnessX;Rotational stiffness value about the x-axis of the coordinate system defined by the instance which uses this resource object.
2353;RotationalStiffnessY;Rotational stiffness value about the y-axis of the coordinate system defined by the instance which uses this resource object.
2354;RotationalStiffnessZ;Rotational stiffness value about the z-axis of the coordinate system defined by the instance which uses this resource object.
2356;WarpingStiffness;Defines the warping stiffness value.
2367;TranslationalStiffnessByLengthX;Translational stiffness value in x-direction of the coordinate system defined by the instance which uses this resource object.
2368;TranslationalStiffnessByLengthY;Translational stiffness value in y-direction of the coordinate system defined by the instance which uses this resource object.
2369;TranslationalStiffnessByLengthZ;Translational stiffness value in z-direction of the coordinate system defined by the instance which uses this resource object.
2370;RotationalStiffnessByLengthX;Rotational stiffness value about the x-axis of the coordinate system defined by the instance which uses this resource object.
2371;RotationalStiffnessByLengthY;Rotational stiffness value about the y-axis of the coordinate system defined by the instance which uses this resource object.
2372;RotationalStiffnessByLengthZ;Rotational stiffness value about the z-axis of the coordinate system defined by the instance which uses this resource object.
2380;TranslationalStiffnessByAreaX;Translational stiffness value in x-direction of the coordinate system defined by the instance which uses this resource object.
2381;TranslationalStiffnessByAreaY;Translational stiffness value in y-direction of the coordinate system defined by the instance which uses this resource object.
2382;TranslationalStiffnessByAreaZ;Translational stiffness value in z-direction of the coordinate system defined by the instance which uses this resource object.
2387;SlippageX;Slippage in x-direction of the coordinate system defined by the instance which uses this resource object.
2388;SlippageY;Slippage in y-direction of the coordinate system defined by the instance which uses this resource object.
2389;SlippageZ;Slippage in z-direction of the coordinate system defined by the instance which uses this resource object.
2393;Name;Optionally defines a name for this connection condition.
2395;TensionFailureX;Tension force in x-direction leading to failure of the connection.
2396;TensionFailureY;Tension force in y-direction leading to failure of the connection.
2397;TensionFailureZ;Tension force in z-direction leading to failure of the connection.
2398;CompressionFailureX;Compression force in x-direction leading to failure of the connection.
2399;CompressionFailureY;Compression force in y-direction leading to failure of the connection.
2400;CompressionFailureZ;Compression force in z-direction leading to failure of the connection.
2406;CfsFaces;The set of faces arcwise connected along common edges or vertices.
2419;EdgeStart;"Start point (vertex) of the edge.
"
2420;EdgeEnd;"End point (vertex) of the edge. The same vertex can be used for both EdgeStart and EdgeEnd.
"
2422;EdgeElement;"Edge entity used to construct this oriented edge.
"
2423;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.
"
2424;EdgeStart;"The start vertex of the oriented edge. It derives from the vertices of the edge element after taking account of the orientation.
"
2425;EdgeEnd;"The end vertex of the oriented edge. It derives from the vertices of the edge element after taking account of the orientation.
"
2430;VertexGeometry;The geometric point, which defines the position in geometric space of the vertex.
2432;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."
2433;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."
2435;ParentEdge;The Edge, or Subedge, which contains the Subedge.
2438;Bounds;"Boundaries of the face.
"
2442;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.
2443;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.
2450;Bound;"The loop which will be used as a face boundary.
"
2451;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.
"
2458;Polygon;List of points defining the loop. There are no repeated points in the list.
2461;LoopVertex;The vertex which defines the entire loop.
2463;EdgeList;A list of oriented edge entities which are concatenated together to form this path.
2464;Ne;The number of elements in the edge list.
2468;EdgeList;The list of oriented edges which are concatenated together to form this path.
2479;Status;"<EPM-HTML>
    Current status of the task.
    <blockquote>
      <b>NOTE:</b> 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'.
    </blockquote>
</EPM-HTML>
"
2480;WorkMethod;"<EPM-HTML>
    The method of work used in carrying out a task.
    <blockquote>
      <font color=""#FF0000""><b>NOTE:</b> This attribute should
      not be used if the work method is specified for the
      <i>IfcTaskType</i></font>
    </blockquote>
</EPM-HTML>"
2481;IsMilestone;"<EPM-HTML>
    Identifies whether a task is a milestone task (=TRUE) or not
    (= FALSE).
    <blockquote>
      <b>NOTE:</b> 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.
    </blockquote>
</EPM-HTML>"
2482;Priority;"<EPM-HTML>
    A value that indicates the relative priority of the task (in
    comparison to the priorities of other tasks).
</EPM-HTML>"
2483;TaskTime;"<EPM-HTML>
    Time related information for the task.
    <blockquote>
      <p>
        <font color=""#0000FF"" size=""-1"">Added in IFC 2x4</font>
      </p>
    </blockquote>
</EPM-HTML>"
2484;PredefinedType;"<EPM-HTML>
    Identifies the predefined types of a task from which 
    the type required may be set.
    <blockquote>
      <p>
        <font color=""#0000FF"" size=""-1"">Added in IFC 2x4</font>
      </p>
    </blockquote>
</EPM-HTML>"
2503;PredefinedType;"<EPM-HTML>
    Identifies the predefined types of a procedure from which 
    the type required may be set.
</EPM-HTML>"
2517;PredefinedType;"<EPM-HTML>
    Identifies the predefined types of an event from which 
    the type required may be set.
</EPM-HTML>"
2518;EventTriggerType;"<EPM-HTML>
    Identifies the predefined types of event trigger from which 
    the type required may be set.
</EPM-HTML>"
2519;UserDefinedEventTriggerType;"<EPM-HTML>
    A user defined event trigger type, the value of which is 
    asserted when the value of an event trigger type is declared 
    as USERDEFINED.
</EPM-HTML>"
2520;EventOccurenceTime;"<EPM-HTML>
    The date and/or time at which an event occurs.
</EPM-HTML>"
2539;CreationDate;"<EPM-HTML>
    The date that the plan is created.
</EPM-HTML>"
2540;Creators;"<EPM-HTML>
    The authors of the work plan.
</EPM-HTML>"
2541;Purpose;"<EPM-HTML>
    A description of the purpose of the work schedule.
</EPM-HTML>"
2542;Duration;"<EPM-HTML>
    The total duration of the entire work schedule.
</EPM-HTML>"
2543;TotalFloat;"<EPM-HTML>
    The total time float of the entire work schedule.
</EPM-HTML>"
2544;StartTime;"<EPM-HTML>
    The start time of the schedule.
</EPM-HTML>"
2545;FinishTime;"<EPM-HTML>
    The finish time of the schedule.
</EPM-HTML>"
2547;PredefinedType;"<EPM-HTML>
    Identifies the predefined types of a work plan from which 
    the type required may be set.
</EPM-HTML>"
2556;PredefinedType;"<EPM-HTML>
    Identifies the predefined types of a work schedule from which 
    the type required may be set.
</EPM-HTML>"
2565;WorkingTimes;"<EPM-HTML>
    Set of times periods that are regarded as an initial set-up
    of working times. Exception times can then further restrict
    these working times.
</EPM-HTML>
"
2566;ExceptionTimes;"<EPM-HTML>
    Set of times periods that define exceptions (non-working
    times) for the given working times including the base
    calendar, if provided.
</EPM-HTML>"
2567;PredefinedType;"<EPM-HTML>
    Identifies the predefined types of a work calendar from which 
    the type required may be set.
    <blockquote>
      <p>
        <font color=""#0000FF"" size=""-1"">Added in IFC 2x4</font>
      </p>
    </blockquote>
</EPM-HTML>"
2576;RelatingProcess;"<EPM-HTML>
    Reference to the process, that is the predecessor.
</EPM-HTML>
"
2577;RelatedProcess;"<EPM-HTML>
   Reference to the process, that is the successor.
</EPM-HTML>
"
2578;TimeLag;"<EPM-HTML>
    Time duration of the sequence, it is the time lag between the
    predecessor and the successor as specified by the
    SequenceType.
</EPM-HTML>
"
2579;SequenceType;"<EPM-HTML>
     The way in which the time lag applies to the sequence.
</EPM-HTML>
"
2580;UserDefinedSequenceType;"<EPM-HTML>
    Allows for specification of user defined type of the sequence
    beyond the enumeration values (START_START, START_FINISH,
    FINISH_START, FINISH_FINISH) provided by <i>SequenceType</i>
    attribute of type <i>IfcSequenceEnum</i>. When a value is
    provided for attribute <i>UserDefinedSequenceType</i> in
    parallel the attribute <i>SequenceType</i> shall have
    enumeration value USERDEFINED.
    <blockquote>
      <p>
        <font color=""#0000FF"" size=""-1"">Added in IFC 2x4</font>
      </p>
    </blockquote>
</EPM-HTML>"
2591;PredefinedType;"<EPM-HTML>
    Identifies the predefined types of a task type from which 
    the type required may be set.
</EPM-HTML>"
2592;WorkMethod;"<EPM-HTML>
    The method of work used in carrying out a task.
</EPM-HTML>"
2595;PredefinedType;"<EPM-HTML>
    Identifies the predefined types of a procedure from which 
    the type required may be set.
</EPM-HTML>"
2598;PredefinedType;"<EPM-HTML>
    Identifies the predefined types of an event from which 
    the type required may be set.
</EPM-HTML>"
2599;EventTriggerType;"<EPM-HTML>
    Identifies the predefined types of event trigger from which 
    the type required may be set.
</EPM-HTML>"
2600;UserDefinedEventTriggerType;"<EPM-HTML>
    A user defined event trigger type, the value of which 
    is asserted when the value of an event trigger type is 
    declared as USERDEFINED.
</EPM-HTML>"
2605;PredefinedType;"<EPM-HTML>
Predefined generic type for a cost schedule that is specified in an enumeration. There may be a property set given specifically for the predefined types.

<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been made optional.</font></small>
</blockquote>

</EPM-HTML>"
2606;Status;"<EPM-HTML>
The current status of a cost schedule. Examples of status values that might be used for a cost schedule status include:
<ul>
<li> PLANNED </li>
<li> APPROVED </li>
<li> AGREED </li>
<li> ISSUED </li>
<li> STARTED </li>
</ul>

</EPM-HTML>"
2607;SubmittedOn;"<EPM-HTML> 
The date and time on which the cost schedule was submitted.
<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE Type changed from IfcDateTimeSelect. 
    </font> 
  </small> 
</blockquote> 
</EPM-HTML> 
"
2608;UpdateDate;"<EPM-HTML> 
The date and time that this cost schedule is updated; this allows tracking the schedule history.
<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE Type changed from IfcDateTimeSelect. 
    </font> 
  </small> 
</blockquote> 
</EPM-HTML> 
"
2620;PredefinedType;"<EPM-HTML>
Predefined generic type for a project order that is specified in an enumeration. There may be a property set given specificly for the predefined types.

<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been made optional.</font></small>
</blockquote>

</EPM-HTML>
"
2621;Status;"<EPM-HTML>The current status of a project order.Examples of status values that might be used for a project order status include:
<ul>
<li>PLANNED</li>
<li>REQUESTED</li>
<li>APPROVED</li>
<li>ISSUED</li>
<li>STARTED</li>
<li>DELAYED</li>
<li>DONE</li>
</ul>
</EPM-HTML>"
2622;LongDescription;"<EPM-HTML>
A detailed description of the project order describing the work to be completed.
</EPM-HTML>"
2632;PredefinedType;"<EPM-HTML>
Predefined generic type for a cost item that is specified in an enumeration. There may be a property set given specificly for the predefined types.

<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added.</font></small>
</blockquote>

</EPM-HTML>
"
2633;CostValues;"<EPM-HTML>
Component costs for which the total cost for the cost item is calculated, and then multiplied by the total <i>CostQuantities</i> if provided.  

If <i>CostQuantities</i> is provided then values indicate unit costs, otherwise values indicate total costs.

For calculation purposes, the cost values may be directly added unless they have qualifications.  Cost values with qualifications (e.g. <i>IfcCostValue.ApplicableDate</i>, <i>IfcCostValue.FixedUntilDate</i>) should be excluded from such calculation if they do not apply.

<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added.</font></small>
</blockquote>

</EPM-HTML>
"
2634;CostQuantities;"<EPM-HTML>
Component quantities of the same type for which the total quantity for the cost item is calculated as the sum.
<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added.</font></small>
</blockquote>
</EPM-HTML>



"
2639;PredefinedType;"<EPM-HTML>
Identifies the predefined types of permit that can be granted.

<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added.</font></small>
</blockquote>

</EPM-HTML>"
2640;Status;"<EPM-HTML>
The status currently assigned to the permit.

<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added.</font></small>
</blockquote>

</EPM-HTML>"
2641;LongDescription;"<EPM-HTML>
Detailed description of the request.

<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added.</font></small>
</blockquote>

</EPM-HTML>"
2649;PredefinedType;"<EPM-HTML>
Identifies the predefined type of sources through which a request can be made.

<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added.</font></small>
</blockquote>

</EPM-HTML>"
2650;Status;"<EPM-HTML>
The status currently assigned to the request.  Possible values include:<br/>
Hold: wait to see if further requests are received before deciding on action<br/>
NoAction: no action is required on this request<br/>
Schedule: plan action to take place as part of maintenance or other task planning/scheduling<br/>
Urgent: take action immediately<br/>

<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added.</font></small>
</blockquote>

</EPM-HTML>"
2651;LongDescription;"<EPM-HTML>
Detailed description of the permit.

<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The attribute has been added.</font></small>
</blockquote>

</EPM-HTML>"
2668;ResourceConsumption;"<EPM-HTML>
Indicates how the resource is consumed or occupied during its use in a process.  Production-based consumption is indicated by CONSUMED, PARTIALLYCONSUMED, or NOTCONSUMED, where QuantityProduced refers to a quantity on the <i>IfcProduct</i> to which the assigned <i>IfcProcess</i> is assigned.  Duration-based occupation is indicated by OCCUPIED, PARTIALLYOCCUPIED, or NOTOCCUPIED, where <i>QuantityProduced</i> refers to a quantity on the <i>IfcProcess</i> to which the resource is assigned.
<p></p>
</EPM-HTML>"
2669;BaseQuantityConsumed;"<EPM-HTML>
The basic (i.e. default, or recommended) unit that should be used for measuring the amount of the resource and the relative quantity of the resource fully or partially consumed.  For labor and equipment resources, this always refers to an <i>IfcDuration</i> quantity, typically 1 hour.  For material resources, this always refers to a spatial quantity (e.g. <i>IfcVolumeMeasure</i>).

<blockquote><font color=""#FF0000"" SIZE=""-1"">
IFC2x4 NOTE: The attribute <i>BaseQuantityConsumed</i> has been renamed from BaseQuantity.
</blockquote>

<p></p>
</EPM-HTML>"
2670;BaseQuantityProduced;"<EPM-HTML>
The basic (i.e. default, or recommended) unit that should be used for measuring the amount of the output (e.g. product volume) and the relative quantity of the output produced per input <i>BaseQuantityConsumed</i>.  If the resource is not assigned to a task, then this value should be null.  For production-based resources (e.g. carpentry labor), this value refers to a product-based spatial quantity (e.g. volume).  For duration-based resources (e.g. safety inspector, fuel for equipment), this value refers to a task-based time quantity (<i>IfcDuration</i>).  

<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote>

<p></p>

</EPM-HTML>"
2671;CostRatesConsumed;"<EPM-HTML>
Indicates the unit costs for which accrued cost amounts should be calculated.  Such unit costs may be split into <i>Name</i> designations (e.g. 'Standard', 'Overtime'), and may contain a hierarchy of cost values that apply at different dates (using <i>IfcCostValue.ApplicableDate</i> and <i>IfcCostValue.FixedUntilDate</i>).  The order of cost rates is significant; time series that break out Costs and Work will list such values in corresponding sequence - see the Time Series Use Definition for detail.

<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote>

<p></p>
</EPM-HTML>"
2672;QuantityProduced;"<EPM-HTML>
Identifies the quantity for which the <i>BaseQuantityProduced</i> applies.  The <i>Name</i> of the <i>IfcPhysicalQuantity</i> identifies the quantity definition being measured, e.g. ""GrossVolume"".  For work-based resources (e.g. carpentry labor), this value refers to a quantity on <i>IfcProduct</i>(s) to which the assigned <i>IfcTask</i> is assigned.  For duration-based resources (e.g. safety inspector, fuel for equipment), this value refers to a quantity on the assigned <i>IfcTask</i>.

<blockquote><font SIZE=""-1"">NOTE: The referenced instance may or may not be the same instance as that on the assigned product or process, as references to non-<i>IfcRoot</i> entities do not imply any semantic relationship, just value sharing (interning). 
</font></blockquote>

<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote>

<p></p>
</EPM-HTML>"
2673;ResourceTime;"<EPM-HTML>
Indicates the work, usage, and times scheduled and completed.  Some attributes on this object may have associated constraints or time series; see documentation of <i>IfcResourceTime</i> for specific usage.  If the resource is nested, then certain values may be calculated based on the component resources as indicated at <i>IfcResourceTime</i>.

<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote>

<p></p>
</EPM-HTML>"
2674;ResourceCost;"<EPM-HTML>
Indicates the costs budgeted and realized.  Some attributes on this object may have associated time series; see documentation of <i>IfcResourceCost</i> for specific usage.  If the resource is nested, then certain values may be calculated based on the component resources as indicated at <i>IfcResourceCost</i>.

<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote>

<p></p>
</EPM-HTML>"
2676;PredefinedType;"<EPM-HTML>
Defines types of construction equipment resources.
<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote>
<p></p>
</EPM-HTML>"
2690;PredefinedType;"<EPM-HTML>
Defines types of labor resources.
<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote><p></p>
</EPM-HTML>"
2715;PredefinedType;"<EPM-HTML>
Defines types of crew resources.
<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote>
<p></p>
</EPM-HTML>"
2723;PredefinedType;"<EPM-HTML>
Defines types of subcontract resources.
<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote>
<p></p>
</EPM-HTML>"
2731;PredefinedType;"<EPM-HTML>
Defines types of construction product resources.
<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote>
<p></p>
</EPM-HTML>"
2739;PredefinedType;"<EPM-HTML>
Defines types of construction material resources.
<blockquote><font color=""#FF0000"" SIZE=""-1"">IFC2x4 New attribute
</blockquote>
<p></p>
</EPM-HTML>"
2769;ResourceConsumption;"<EPM-HTML>
Indicates how the resource is consumed or occupied during its use in a process.  Production-based consumption is indicated by CONSUMED, PARTIALLYCONSUMED, or NOTCONSUMED, where QuantityProduced refers to a quantity applicable to the <i>IfcTypeProduct</i> to which the assigned <i>IfcTypeProcess</i> is assigned.  Duration-based occupation is indicated by OCCUPIED, PARTIALLYOCCUPIED, or NOTOCCUPIED, where <i>QuantityProduced</i> refers to a quantity applicable to the the <i>IfcTypeProcess</i> to which the resource is assigned.<p></p>
</EPM-HTML>"
2770;BaseQuantityConsumed;"<EPM-HTML>
The basic (i.e. default, or recommended) unit that should be used for measuring the amount of the resource and the relative quantity of the resource fully or partially consumed.  For labor and equipment resources, this always refers to an <i>IfcDuration</i> quantity, typically 1 hour.  For material resources, this always refers to a spatial quantity (e.g. <i>IfcVolumeMeasure</i>).

<p></p>
</EPM-HTML>"
2771;BaseQuantityProduced;"<EPM-HTML>
The basic (i.e. default, or recommended) unit that should be used for measuring the amount of the output (e.g. product volume) and the relative quantity of the output produced per input <i>BaseQuantityConsumed</i>.  If the resource type is not assigned to a task type, then this value should be null.  For production-based resources (e.g. carpentry labor), this value refers to a product-based spatial quantity (e.g. volume).  For duration-based resources (e.g. safety inspector, fuel for equipment), this value refers to a task-based time quantity (<i>IfcDuration</i>).  

<p></p>

</EPM-HTML>"
2772;CostRatesConsumed;"<EPM-HTML>
Indicates the unit costs for which accrued cost amounts should be calculated.  Such unit costs may be split into <i>Name</i> designations (e.g. 'Standard', 'Overtime'), and may contain a hierarchy of cost values that apply at different dates (using <i>IfcCostValue.ApplicableDate</i> and <i>IfcCostValue.FixedUntilDate</i>).  The order of cost rates is significant; resource occurrences having time series that break out Costs and Work will list such values in corresponding sequence - see the Time Series Use Definition at <i>IfcConstructionResource</i> for detail.

<p></p>
</EPM-HTML>"
2773;QuantityProduced;"<EPM-HTML>
Identifies the quantity for which the <i>BaseQuantityProduced</i> applies.  The <i>Name</i> of the <i>IfcPhysicalQuantity</i> identifies the quantity definition being measured, e.g. ""GrossVolume"".  For production-based resources (e.g. carpentry labor), this value refers to quantities on <i>IfcProduct</i>(s) to which the assigned <i>IfcTask</i> is assigned.  For duration-based resources (e.g. safety inspector, fuel for equipment), this value refers to quantities that may be assigned to occurrences of the assigned <i>IfcTaskType</i>.

<p></p>
</EPM-HTML>"
2775;PredefinedType;"<EPM-HTML>
Defines types of crew resources.
<p></p>
</EPM-HTML>"
2778;PredefinedType;"<EPM-HTML>
Defines types of labor resources.
<p></p>
</EPM-HTML>"
2781;PredefinedType;"<EPM-HTML>
Defines types of subcontract resources.
<p></p>
</EPM-HTML>"
2784;PredefinedType;"<EPM-HTML>
Defines types of construction material resources.
<p></p>
</EPM-HTML>"
2787;PredefinedType;"<EPM-HTML>
Defines types of construction equipment resources.
<p></p>
</EPM-HTML>"
2790;PredefinedType;"<EPM-HTML>
Defines types of construction product resources.
<p></p>
</EPM-HTML>"
2794;PredefinedType;<EPM-HTML><p>Identifies the predefined types of motor connection from which the type required may be set.</p></EPM-HTML>
2797;PredefinedType;<EPM-HTML><p>Identifies the predefined types of outlet from which the type required may be set.</p></EPM-HTML>
2808;PredefinedType;<EPM-HTML><p>Identifies the predefined types of electrical appliance from which the type required may be set.</p></EPM-HTML>
2830;PredefinedType;<EPM-HTML><p>Identifies the predefined types of light fixture from which the type required may be set.</p></EPM-HTML>
2839;PredefinedType;<EPM-HTML><p>Identifies the predefined types of lamp from which the type required may be set.</p></EPM-HTML>
2854;PredefinedType;<EPM-HTML><p>Identifies the predefined types of audio-visual appliance from which the type required may be set.</p></EPM-HTML>
2871;PredefinedType;<EPM-HTML><p>Identifies the predefined types of communications  appliance from which the type required may be set.</p></EPM-HTML>
2889;PredefinedType;<EPM-HTML><p>Identifies the predefined types of switch from which the type required may be set.</p></EPM-HTML>
2904;PredefinedType;<EPM-HTML><p>Identifies the predefined types of electrical time control from which the type required may be set.</p></EPM-HTML>
2913;PredefinedType;<EPM-HTML><p>Identifies the predefined types of protective device from which the type required may be set.</p></EPM-HTML>
2926;PredefinedType;<EPM-HTML><p>Identifies the predefined types of electric distribution type from which the type required may be set.</p></EPM-HTML>
2936;PredefinedType;<EPM-HTML><p>Identifies the predefined types of cable carrier fitting from which the type required may be set.</p></EPM-HTML>
2946;PredefinedType;<EPM-HTML><p>Identifies the predefined types of junction boxes from which the type required may be set.</p></EPM-HTML>
2954;PredefinedType;<EPM-HTML><p>Identifies the predefined types of cable fitting from which the type required may be set.</p></EPM-HTML>
2965;PredefinedType;<EPM-HTML><p>Identifies the predefined types of electric flow storage devices from which the type required may be set.</p></EPM-HTML>
2976;PredefinedType;<EPM-HTML><p>Identifies the predefined types of cable segment from which the type required may be set.</p></EPM-HTML>
2986;PredefinedType;<EPM-HTML><p>Identifies the predefined types of cable carrier segment from which the type required may be set.</p></EPM-HTML>
2996;PredefinedType;<EPM-HTML><p>Identifies the predefined types of protective device tripping unit types from which the type required may be set.</p></EPM-HTML>
3006;PredefinedType;<EPM-HTML><p>Identifies the predefined types of cable segment from which the type required may be set.</p></EPM-HTML>
3010;PredefinedType;<EPM-HTML><p>Identifies the predefined types of cable carrier segment from which the type required may be set.</p></EPM-HTML>
3014;PredefinedType;<EPM-HTML><p>Identifies the predefined types of cable carrier fitting from which the type required may be set.</p></EPM-HTML>
3018;PredefinedType;<EPM-HTML><p>Identifies the predefined types of cable fitting from which the type required may be set.</p></EPM-HTML>
3022;PredefinedType;
3026;PredefinedType;
3030;PredefinedType;
3034;PredefinedType;
3038;PredefinedType;
3042;PredefinedType;
3046;PredefinedType;
3050;PredefinedType;
3054;PredefinedType;
3058;PredefinedType;
3062;PredefinedType;
3066;PredefinedType;
3070;PredefinedType;
3082;PredefinedType;
3092;PredefinedType;
3104;PredefinedType;
3114;PredefinedType;
3123;PredefinedType;
3127;PredefinedType;<EPM-HTML><p>Identifies the predefined types of electric generators from which the type required may be set.</p></EPM-HTML>
3130;PredefinedType;<EPM-HTML><p>Identifies the predefined types of transformer from which the type required may be set.</p></EPM-HTML>
3133;PredefinedType;<EPM-HTML><p>Identifies the predefined types of electric motor from which the type required may be set.</p></EPM-HTML>
3136;PredefinedType;
3140;PredefinedType;"Defines the type of air to air heat recovery device.
"
3155;PredefinedType;Defines types of boilers.
3163;PredefinedType;
3169;PredefinedType;Defines the typical types of chillers (e.g., air-cooled, water-cooled, etc.).
3178;PredefinedType;"Defines typical types of coils (e.g., Cooling, Heating, etc.)
"
3191;PredefinedType;Defines the type of condenser.
3204;PredefinedType;Defines the type of cooled beam.
3212;PredefinedType;Defines the typical types of cooling towers (e.g., OpenTower, ClosedTower, CrossFlow, etc.).
3221;PredefinedType;Defines the type of evaporative cooler.
3236;PredefinedType;Defines the type of evaporator.
3248;PredefinedType;Defines the basic types of heat exchanger (e.g., plate, shell and tube, etc.).
3256;PredefinedType;Defines the type of humidifier.
3275;PredefinedType;Defines the type of tube bundle.
3282;PredefinedType;The type of unitary equipment.
3293;PredefinedType;
3301;PredefinedType;Defines the type of fan typically used in building services.
3314;PredefinedType;Defines the type of compressor (e.g., hermetic, reciprocating, etc.).
3335;PredefinedType;Defines the type of pump typically used in building services.
3348;PredefinedType;Type of damper.
3365;PredefinedType;The air terminal box type.
3374;PredefinedType;The type of valve.
3401;PredefinedType;Defines the type of flow meter.
3411;PredefinedType;The type of duct fitting.
3424;PredefinedType;The type of pipe fitting.
3437;PredefinedType;Defines the type of tank.
3450;PredefinedType;The type of duct silencer.
3459;PredefinedType;The type of air filter.
3471;PredefinedType;The type of pipe segment.
3482;PredefinedType;The type of duct segment.
3490;PredefinedType;
3494;PredefinedType;
3498;PredefinedType;
3502;PredefinedType;
3506;PredefinedType;
3510;PredefinedType;
3514;PredefinedType;
3518;PredefinedType;
3522;PredefinedType;
3526;PredefinedType;
3537;PredefinedType;
3546;PredefinedType;
3558;PredefinedType;
3562;PredefinedType;
3566;PredefinedType;
3570;PredefinedType;
3574;PredefinedType;
3578;PredefinedType;
3582;PredefinedType;
3586;PredefinedType;
3590;PredefinedType;
3594;PredefinedType;
3598;PredefinedType;
3602;PredefinedType;
3606;PredefinedType;
3610;PredefinedType;
3614;PredefinedType;
3618;PredefinedType;
3622;PredefinedType;
3626;PredefinedType;
3630;PredefinedType;
3634;PredefinedType;
3638;PredefinedType;
3641;PredefinedType;Enumeration of possible types of space heater (e.g., baseboard heater, convector, radiator, etc.).
3644;PredefinedType;
3647;PredefinedType;
3656;PredefinedType;Defines the type of vibration isolator.
3660;PredefinedType;<EPM-HTML><p>Identifies the predefined types of waste terminal from which the type required may be set.</p></EPM-HTML>
3673;PredefinedType;<EPM-HTML><p>Identifies the predefined types of stack terminal from which the type required may be set.</p></EPM-HTML>
3682;PredefinedType;<EPM-HTML><p>Identifies the predefined types of sanitary terminal from which the type required may be set.</p></EPM-HTML>
3698;PredefinedType;<EPM-HTML><p>Identifies the predefined types of fire suppression terminal from which the type required may be set.</p></EPM-HTML>
3709;PredefinedType;
3713;PredefinedType;
3717;PredefinedType;
3721;PredefinedType;
3725;PredefinedType;
3735;PredefinedType;
3743;Source;"<EPM-HTML>
Source (or publisher) for this classification.
<blockquote>
  <small>
NOTE that the source of the classification means the person or organization that was the original author or the person or organization currently acting as the publisher. 
  </small>
</blockquote>
</EPM-HTML>"
3744;Edition;"<EPM-HTML>
The edition or version of the classification system from which the classification notation is derived.
<blockquote>
  <small>
    NOTE the version labeling system is specific to the classification system. 
  </small><br>
  <small>
    <font color=#ff0000"">
      IFC2x4 CHANGE The attribute has been changed to be optional.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3745;EditionDate;"<EPM-HTML>The date on which the edition of the classification used became valid.
<blockquote>
  <small>
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.
  </small>
</blockquote>
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE The data type has been changed to <i>IfcDate</i>, the date string according to ISO8601.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3746;Name;"<EPM-HTML>
The name or label by which the classification used is normally known.
<blockquote>
  <small>
    NOTE Examples of names include CI/SfB, Masterformat, BSAB, Uniclass, STABU, DIN276, DIN277 etc.
  </small>
</blockquote>
</EPM-HTML>"
3747;Description;"<EPM-HTML>
Additional description provided for the classification.
<blockquote><p>
  <span style=""font-size:smaller;color:red"">
     IFC2x4 CHANGE&nbsp; New attribute added at the end of the attribute list.
  </span>
</p></blockquote>
</EPM-HTML>"
3748;Location;"<EPM-HTML>Resource identifier or locator, provided as URI, URN or URL, of the classification.  
<blockquote><p>
  <span style=""font-size:smaller;color:red"">
     IFC2x4 CHANGE&nbsp; New attribute added at the end of the attribute list.
  </span>
</p></blockquote>
<EPM-HTML>"
3749;ReferenceTokens;"<EPM-HTML>
The delimiter tokens that are used to mark the boundaries of individual facets (substrings) in a classification reference.
<br><br>
This typically applies then the <i>IfcClassification</i> is used in
conjuction with <i>IfcClassificationReference</i>'s. If only one <i>ReferenceToken</i> is provided, it applies to all boundaries of individual facets, if more than one <i>ReferenceToken</i> are provided, the first token applies to the first boundary, the second token to the second boundary, and the n<super>th</super> token to the n<super>th</super> and any additional boundary. 
<blockquote>
  <small>
NOTE&nbsp; Tokens are typically recommended within the classification itself and each token will have a particular role.
  </small><br>
  <small>
EXAMPLE 1&nbsp; To indicate that the facet delimiter used for DIN277-2 reference key ""2.1"" (""Office rooms"") is ""."", a single <i>ReferenceToken</i> ['.'] is provided. To indicate that the facet delimiter used for Omniclass Table 13 (space by function) reference key ""13-15 11 34 11"" (""Office"") are ""-"" and "" "", two <i>ReferenceToken</i>'s ['-', ' '] are provided. 
  </small><br>
  <small>
EXAMPLE 2&nbsp; The use of <i>ReferenceTokens</i> can also be extended to include masks. The use need to be agreed in view definitions or implementer agreements that stipulates a ""mask syntax"" that should be used.  
  </small>
</blockquote>
<blockquote><p>
  <span style=""font-size:smaller;color:red"">
     IFC2x4 CHANGE&nbsp; New attribute added at the end of the attribute list.
  </span>
</p></blockquote>
</EPM-HTML>"
3750;ClassificationForObjects;"<EPM-HTML>
The classification with which objects are associated.
<blockquote>
  <small><font color=""#ff0000"">
    IFC2x4 CHANGE&nbsp; New inverse attribute.
  </font></small>
</blockquote>
</EPM-HTML>"
3751;HasReferences;"<EPM-HTML>
The classification references to which the classification applies. It can either be the final classification notation, or an intermediate classification item.
</EPM-HTML>"
3757;Name;<EPM-HTML>The name which is used to identify the library.</EPM-HTML>
3758;Version;<EPM-HTML>Identifier for the library version used for reference.</EPM-HTML>
3759;Publisher;<EPM-HTML>Information of the organization that acts as the library publisher.</EPM-HTML>
3760;VersionDate;"<EPM-HTML>
Date of the referenced version of the library.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE&nbsp; The data type has been changed to <i>IfcDate</i>, the date string according to ISO8601.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3761;Location;"<EPM-HTML>
Resource identifier or locator, provided as URI, URN or URL, of the library information for online references.
<blockquote><p>
  <span style=""font-size:smaller;color:red"">
     IFC2x4 CHANGE&nbsp; New attribute added at the end of the attribute list.
  </span>
</p></blockquote>
</EPM-HTML>"
3762;LibraryInfoForObjects;"<EPM-HTML>
The library information with which objects are associated.
<blockquote>
  <small><font color=""#ff0000"">
    IFC2x4 CHANGE&nbsp; New inverse attribute.
  </font></small>
</blockquote>
</EPM-HTML>"
3763;HasLibraryReferences;<EPM-HTML>The library references to which the library information applies.</EPM-HTML>
3766;Description;"<EPM-HTML>
Additional description provided for the library reference.
<blockquote><p>
  <span style=""font-size:smaller;color:red"">
     IFC2x4 CHANGE&nbsp; New attribute added at the end of the attribute list.
  </span>
</p></blockquote>
</EPM-HTML>"
3767;Language;"<EPM-HTML>The language in which a library reference is expressed.
<blockquote><p>
  <span style=""font-size:smaller;color:red"">
     IFC2x4 CHANGE&nbsp; New attribute added at the end of the attribute list.
  </span>
</p></blockquote>
</EPM-HTML>"
3768;ReferencedLibrary;<EPM-HTML>The library information that is being referenced.</EPM-HTML>
3769;LibraryRefForObjects;"<EPM-HTML>
The library reference with which objects are associated.
<blockquote>
  <small><font color=""#ff0000"">
    IFC2x4 CHANGE&nbsp; New inverse attribute.
  </font></small>
</blockquote>
</EPM-HTML>"
3774;Location;"<EPM-HTML>
Location, where the external source (classification, document or library) can be accessed by electronic means. The electronic location is provided as an URI, and would normally be given as an URL location string.
<blockquote><p>
  <span style=""font-size:smaller;color:red"">
    IFC2x4 CHANGE&nbsp; The data type has been changed from <em>IfcLabel</em> to <em>IfcURIReference</em>.
  </span>
</p></blockquote>
<EPM-HTML>
"
3775;Identification;"<EPM-HTML>
The <i>Identification</i> provides a unique identifier of the referenced item within the external source (classification, document or library). It may be provided as 
<ul>
 <li>a key, e.g. a classification notation, like NF2.3</li>
 <li>a handle</li>
 <li>a uuid or guid</li>
</ul>
It may be human readable (such as a key) or not (such as a handle or uuid) depending on the context of its usage (which has to be determined by local agreement).
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE  Attribute renamed from <i>ItemReference</i> for consistency.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3776;Name;<EPM-HTML>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).<EPM-HTML>
3777;ExternalReferenceForResources;"<EPM-HTML>
Reference to all associations between this external reference and objects within the <i>IfcResourceObjectSelect</i> that are tagged by the external reference.
<blockquote>
  <small>
    <font color=""FF0000"">
IFC2x4 CHANGE&nbsp; New inverse attribute added with upward compatibility.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3780;ReferencedSource;<EPM-HTML>The classification system or source that is referenced.</EPM-HTML>
3781;Description;"<EPM-HTML>
Description of the classification reference for informational purposes.
<blockquote><p>
  <span style=""font-size:smaller;color:red"">
     IFC2x4 CHANGE&nbsp; New attribute added at the end of the attribute list.
  </span>
</p></blockquote>
</EPM-HTML>"
3782;ClassificationRefForObjects;"<EPM-HTML>
The classification reference with which objects are associated.
<blockquote>
  <small><font color=""#ff0000"">
    IFC2x4 CHANGE&nbsp; New inverse attribute.
  </font></small>
</blockquote>
</EPM-HTML>"
3783;HasReferences;"<EPM-HTML>
The parent classification references to which this child classification reference applies. It can either be the final classification item leaf node, or an intermediate classification item.
<blockquote>
  <small>
    <font color=""#ff0000"">
      IFC2x4 CHANGE  New inverse attribute.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3788;Description;"<EPM-HTML>
Description of the document reference for informational purposes.
<blockquote><p>
  <span style=""font-size:smaller;color:red"">
     IFC2x4 CHANGE&nbsp; New attribute added at the end of the attribute list.
  </span>
</p></blockquote>
</EPM-HTML>"
3789;ReferencedDocument;<EPM-HTML>The document that is referenced.</EPM-HTML>
3790;DocumentRefForObjects;"<EPM-HTML>
The document reference with which objects are associated.
<blockquote>
  <small><font color=""#ff0000"">
    IFC2x4 CHANGE&nbsp; New inverse attribute.
  </font></small>
</blockquote>
</EPM-HTML>"
3793;DocumentId;<EPM-HTML>Identifier that uniquely identifies a document.</EPM-HTML>
3794;Name;<EPM-HTML>File name or document name assigned by owner.</EPM-HTML>
3795;Description;<EPM-HTML>Description of document and its content.</EPM-HTML>
3796;Purpose;<EPM-HTML>Purpose for this document.</EPM-HTML>
3797;IntendedUse;<EPM-HTML>Intended use for this document.</EPM-HTML>
3798;Scope;<EPM-HTML>Scope for this document.</EPM-HTML>
3799;Revision;<EPM-HTML>Document revision designation.</EPM-HTML>
3800;DocumentOwner;<EPM-HTML>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.</EPM-HTML>
3801;Editors;<EPM-HTML>The persons and/or organizations who have created this document or contributed to it.</EPM-HTML>
3802;CreationTime;"<EPM-HTML>
Date and time stamp when the document was originally created.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE The data type has been changed to <i>IfcDateTime</i>, the date time string according to ISO8601.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3803;LastRevisionTime;"<EPM-HTML>
Date and time stamp when this document version was created.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE The data type has been changed to <i>IfcDateTime</i>, the date time string according to ISO8601.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3804;ElectronicFormat;<EPM-HTML>Describes the electronic format of the document being referenced, providing the file extension and the manner in which the content is provided.</EPM-HTML>
3805;ValidFrom;"<EPM-HTML>
Date when the document becomes valid.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE The data type has been changed to <i>IfcDate</i>, the date string according to ISO8601.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3806;ValidUntil;"<EPM-HTML>
Date until which the document remains valid.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE The data type has been changed to <i>IfcDate</i>, the date string according to ISO8601.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3807;Confidentiality;<EPM-HTML>The level of confidentiality of the document.</EPM-HTML>
3808;Status;"<EPM-HTML>The current status of the document. Examples of status values that might be used for a document information status include:<BR>
- DRAFT<BR>
- FINAL DRAFT<BR>
- FINAL<BR>
- REVISION</EPM-HTML>"
3809;Location;"<EPM-HTML>Resource identifier or locator, provided as URI, URN or URL, of the document information for online references.
<blockquote>
  <small><font color=""#ff0000"">
    IFC2x4 CHANGE&nbsp; New attribute added at end of attribute list.
  </font></small>
</blockquote>
</EPM-HTML>"
3810;DocumentInfoForObjects;"<EPM-HTML>
The document information with which objects are associated.
<blockquote>
  <small><font color=""#ff0000"">
    IFC2x4 CHANGE&nbsp; New inverse attribute.
  </font></small>
</blockquote>
</EPM-HTML>"
3811;HasDocumentReferences;<EPM-HTML>The document references to which the document applies</EPM-HTML>
3812;IsPointedTo;<EPM-HTML>An inverse relationship from the IfcDocumentInformationRelationship to the related documents./EPM-HTML>
3813;IsPointer;<EPM-HTML>An inverse relationship from the IfcDocumentInformationRelationship to the relating document.</EPM-HTML>
3815;FileExtension;<EPM-HTML>File extension of electronic document used by computer operating system.</EPM-HTML>
3816;MimeContentType;<EPM-HTML>Main Mime type (as published by W3C or as user defined application type).</EPM-HTML>
3817;MimeSubtype;<EPM-HTML>Mime subtype information.</EPM-HTML>
3833;RelatingDocument;<EPM-HTML>The document that acts as the parent, referencing or original document in a relationship.</EPM-HTML>
3834;RelatedDocuments;<EPM-HTML>The document that acts as the child, referenced or replacing document in a relationship.</EPM-HTML>
3835;RelationshipType;<EPM-HTML>Describes the type of relationship between documents. This could be sub-document, replacement etc. The interpretation has to be established in an application context.</EPM-HTML>
3847;Name;<EPM-HTML><P>A name used to identify or qualify the relationship.</P></EPM-HTML>
3848;Description;<EPM-HTML><P>A description that may apply additional information about the relationship.</P></EPM-HTML>
3850;RelatingReference;"<EPM-HTML>
An external reference that can be used to tag an object within the range of <i>IfcResourceObjectSelect</i>.
<blockquote>
  <p>
    <small>
NOTE&nbsp; External references can be a library reference (for example a dictionary or a catalogue reference), a classification reference, or a documentation reference.
    </small>
  </p>
</blockquote>
</EPM-HTML>"
3851;RelatedResourceObjects;<EPM-HTML><P>Objects within the list of <i>IfcResourceObjectSelect</i> that can be tagged by an external reference to a dictionary, library, catalogue, classification or documentation.</P></EPM-HTML>
3880;Name;A name to be used for the constraint (e.g., ChillerCoefficientOfPerformance).
3881;Description;A description that may apply additional information about a constraint.
3882;ConstraintGrade;Enumeration that qualifies the type of constraint.
3883;ConstraintSource;Any source material, such as a code or standard, from which the constraint originated.
3884;CreatingActor;Person and/or organization that has created the constraint.
3885;CreationTime;"<EPM-HTML>
Time when information specifying the constraint instance was created.
<blockquote>
  <small><font color=""#FF0000"">Note IFC2x4 CHANGE: Attribute data type changed to <i>IfcDateTime</i> using ISO 8601 representation 
  </font></small>
</blockquote>
</EPM-HTML>"
3886;UserDefinedGrade;"Allows for specification of user defined grade of the constraint  beyond the enumeration values (hard, soft, advisory) provided by ConstraintGrade attribute of type <I>IfcConstraintEnum</I>. 
When a value is provided for attribute UserDefinedGrade in parallel the attribute ConstraintGrade shall have enumeration value USERDEFINED."
3887;HasExternalReferences;"<EPM-HTML>
Reference to an external references, e.g. library, classification, or document information, that are associated to the constraint.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE New inverse attribute.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
3888;IsRelatedWith;References to the objectified relationships that relate this constraint with other constraints.
3889;RelatesConstraints;"<EPM-HTML>
References to the objectified relationships that relate other constraints with this constraint.

<blockquote><small>
<font color=""#ff0000"">NOTE &nbsp; For an aggregated constraint, only one instance of <i>IfcConstraintAggregationRelationship</i> shall be set of RelatesConstraints.</font>
</small></blockquote>

</EPM-HTML>"
3890;PropertiesForConstraint;Reference to the properties to which the constraint is applied.
3894;BenchmarkValues;A list of any benchmark values used for comparison purposes.
3895;ResultValues;A list of any resultant values used for comparison purposes.
3896;ObjectiveQualifier;"Enumeration that qualifies the type of objective constraint.
"
3897;UserDefinedQualifier;<EPM-HTML>A user defined value that qualifies the type of objective constraint when ObjectiveQualifier attribute of type <I>IfcObjectiveEnum</I> has value USERDEFINED.</EPM-HTML>
3900;Benchmark;"Enumeration that identifies the type of benchmark data.
"
3901;ValueSource;"Reference source for data values.
"
3902;DataValue;"The value with data type defined by the underlying type accesses via <i>IfcMetricValueSelect</i>.
"
3938;RelatingConstraint;The constraint that is to be related.
3939;RelatedResourceObjects;The properties to which a constraint is to be related.
3942;RelatingConstraint;Constraint with which the other Constraints referenced by attribute RelatedConstraints are related.
3943;RelatedConstraints;Constraints that are related with the one referenced as RelatingConstraint.
3946;LogicalAggregator;"Enumeration that identifies the logical type of aggregation.
"
3955;CostType;"<EPM-HTML>Specification of the type of cost type used.

<BLOCKQUOTE>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.</BLOCKQUOTE>
 
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.
</EPM-HTML>

"
3956;Condition;The condition under which a cost value applies.
3959;Name;A name or additional clarification given to a cost value.
3960;Description;The description that may apply additional information about a cost value.
3961;AppliedValue;The extent or quantity or amount of an applied value.
3962;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).
"
3963;ApplicableDate;"<EPM-HTML> 
The date on or from which an applied value is applicable.
<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE Type changed from IfcDateTimeSelect. 
    </font> 
  </small> 
</blockquote> 
</EPM-HTML> 
"
3964;FixedUntilDate;"<EPM-HTML> 
The date until which applied value is applicable.
<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE Type changed from IfcDateTimeSelect. 
    </font> 
  </small> 
</blockquote> 
</EPM-HTML> 
"
3965;HasExternalReference;"<EPM-HTML> 
Reference to an external reference, e.g. library, classification, or document information, that is associated to the IfcAppliedValue. 
<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE New inverse attribute. 
    </font> 
  </small> 
</blockquote> 
</EPM-HTML> 
"
3966;ValueOfComponents;The total (or subtotal) value of the components within the applied value relationship expressed as a single applied value.
3967;IsComponentIn;The value of the single applied value which is used by the applied value relationship to express a complex applied value.
3974;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.
3975;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.
3976;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).
3977;RateDateTime;"<EPM-HTML> 
The date and time at which an exchange rate applies.
<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE Type changed from IfcDateTimeSelect. Attribute made optional.
    </font> 
  </small> 
</blockquote> 
</EPM-HTML> 
"
3978;RateSource;The source from which an exchange rate is obtained.
3980;ComponentOfTotal;The applied value (total or subtotal) of which the value being considered is a component.
3981;Components;Applied values that are components of another applied value and from which that applied value may be deduced.
3982;ArithmeticOperator;The arithmetic operator applied in an applied value relationship.
3990;Name;"<EPM-HTML> 
Optional name to indicate rate table designation, e.g. ""A"", ""B"".  If provided, then the amounts are based upon <i>IfcCostValue</i> rates having the same <i>Name</i>, where such rates are defined on the referencing <i>IfcConstructionResource</i>.
<P></P>
</EPM-HTML>"
3991;DataOrigin;"<EPM-HTML> 
Indicates the origin of cost data:<br/>
MEASURED indicates firm values considered final;<br/>
PREDICTED indicates estimated values considered tentative;<br/>
SIMULATED indicates calculated values based on effective rates and the scheduled work times.<br/>
<P></P>
</EPM-HTML>"
3992;UserDefinedDataOrigin;"<EPM-HTML> 
Indicates a custom data origin if DataOrigin is set to USERDEFINED.<br/>
<P></P>
</EPM-HTML>"
3993;StatusDate;"<EPM-HTML> 
Indicates the date for which the information is applicable, particularly earned value calculations (PlannedValue, EarnedValue, ActualValue) which rely on the status date and associated time series at the referencing <i>IfcConstructionResource</i>. 
<P></P>
</EPM-HTML>"
3994;ScheduleCost;"<EPM-HTML> 
Indicates the total budgeted cost on behalf of the resource, optionally for a particular task.  
This attribute may be time-phased using <i>IfcRelAssociatesTimeSeries</i> on <i>IfcConstructionResource</i> having <i>Name</i> 'ResourceCost.ScheduleCost'.
<P></P>
</EPM-HTML>"
3995;ActualCost;"<EPM-HTML> 
Indicates the total actual cost incurred on behalf of the resource, optionally for a particular task.  
This attribute may be time-phased using <i>IfcRelAssociatesTimeSeries</i> on <i>IfcConstructionResource</i> having <i>Name</i> 'ResourceCost.ActualCost'.
<P></P>
</EPM-HTML>"
3996;RemainingCost;"<EPM-HTML> 
Indicates the total remaining cost on behalf of the resource, optionally for a particular task.  
This attribute may be time-phased using <i>IfcRelAssociatesTimeSeries</i> on <i>IfcConstructionResource</i> having <i>Name</i> 'ResourceCost.RemainingCost'.
<P></P>
</EPM-HTML>"
3997;PlannedValue;"<EPM-HTML> 
Indicates the Planned Value (PV) which is the sum of the <i>ScheduleCost</i> time series of work scheduled to be completed as of the <i>StatusDate</i>.  Also referred to as Budgeted Cost of Work Scheduled (BCWS).
<P></P>
</EPM-HTML>"
3998;EarnedValue;"<EPM-HTML> 
Indicates the Earned Value (EV) which is the sum of the <i>ScheduleCost</i> time series of work actually completed as of the <i>StatusDate</i>.  Also referred to as Budgeted Cost of Work Performed (BCWP).
<P></P>
</EPM-HTML>"
3999;ActualValue;"<EPM-HTML> 
Indicates the Actual Cost of Work Performed (ACWP) which is the sum of the <i>ActualCost</i> time series of work actually completed as of the <i>StatusDate</i>.  Note that this is not necessarily the same as <i>ActualCost</i> which is the sum of all actual work recorded regardless of status date (i.e. actual work may be recorded after the status date which would not be included). 
<P></P>
</EPM-HTML>"
4008;Name;An unique name for the time series.
4009;Description;A text description of the data that the series represents.
4010;StartTime;The start time of a time series.
4011;EndTime;The end time of a time series.
4012;TimeSeriesDataType;The time series data type.
4013;DataOrigin;The orgin of a time series data.
4014;UserDefinedDataOrigin;Value of the data origin if DataOrigin attribute is USERDEFINED.
4015;Unit;"<EPM-HTML>
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 <I>IfcValue</I>, as defined at <I>IfcProject.UnitsInContext</I> is used.
</EPM-HTML>"
4016;HasExternalReference;"<EPM-HTML> 
Reference to an external reference, e.g. library, classification, or document information, that is associated to the IfcTimeSeries. 
<blockquote> 
  <small> 
    <font color=""#ff0000""> 
IFC2x4 CHANGE New inverse attribute. 
    </font> 
  </small> 
</blockquote> 
</EPM-HTML> 
"
4018;TimeStep;A duration of time intervals between values.
4019;Values;The collection of time series values.
4021;ListValues;A list of time-series values. At least one value is required.
4023;Values;The collection of time series values.
4025;TimeStamp;The specification of the time point.
4026;ListValues;A list of time-series values. At least one value is required.
4043;DurationType;"<EPM-HTML>
    Enables to specify the type of duration values for <i>ScheduleDuration</i>,        <i>ActualDuration</i> and <i>RemainingTime</i>. The duration type is either
     work time or elapsed time.
</EPM-HTML>"
4044;ScheduleDuration;"<EPM-HTML>
    The amount of time which is scheduled for completion of a
    task.
    The value might be measured or somehow calculated, which is defined by
    <i>ScheduleDataOrigin</i>. 
    The value is either given as elapsed time or work time, which is defined by
    <i>DurationType</i>.
    <p>
      <b>NOTE:</b> Scheduled Duration may be calculated as the
      time from scheduled start date to scheduled finish date.
    </p>

</EPM-HTML>
"
4045;ScheduleStart;"<EPM-HTML>
    The date on which a task is scheduled to be started. 
    The value might be measured or somehow calculated, which is defined by
    <i>ScheduleDataOrigin</i>.
    <p>
      <b>NOTE:</b> The scheduled start date must be greater than
      or equal to the earliest start date.
    </p>
</EPM-HTML>"
4046;ScheduleFinish;"<EPM-HTML>
    The date on which a task is scheduled to be finished.
    The value might be measured or somehow calculated, which is defined by
    <i>ScheduleDataOrigin</i>.
    <p>
      <b>NOTE:</b> The scheduled finish date must be greater than
      or equal to the earliest finish date.
    </p>
</EPM-HTML>"
4047;EarlyStart;"<EPM-HTML>
     The earliest date on which a task can be started. It is a calculated value.
</EPM-HTML>"
4048;EarlyFinish;"<EPM-HTML>
    The earliest date on which a task can be finished. It is a calculated value.
</EPM-HTML>"
4049;LateStart;"<EPM-HTML>
     The latest date on which a task can be started. It is a calculated value.
</EPM-HTML>"
4050;LateFinish;"<EPM-HTML>
    The latest date on which a task can be finished. It is a calculated value.
</EPM-HTML>"
4051;FreeFloat;"<EPM-HTML>
      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. It is a calculated elapsed time value.
</EPM-HTML>"
4052;TotalFloat;"<EPM-HTML>
     The difference between the duration available to carry out
     a task and the scheduled duration of the task. It is a calculated 
     elapsed time value.
    <p>
      <b>NOTE:</b> 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.
    </p>
</EPM-HTML>"
4053;IsCritical;"<EPM-HTML>
     A flag which identifies whether a scheduled task is a
     critical item within the programme.
    <p>
      <b>NOTE:</b> A task becomes critical when the float time
      becomes zero or negative.
    </p>
</EPM-HTML>"
4054;StatusTime;"<EPM-HTML>
      The date or time at which the status of the tasks within
      the schedule is analyzed.
</EPM-HTML>"
4055;ActualDuration;"<EPM-HTML>
    The actual duration of the task. It is a measured value.
    The value is either given as elapsed time or work time, which is defined by
    <i>DurationType</i>.
</EPM-HTML>"
4056;ActualStart;"<EPM-HTML>
     The date on which a task is actually started. It is a measured value.
    <p>
      <b>NOTE:</b> 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.
    </p>
</EPM-HTML>"
4057;ActualFinish;"<EPM-HTML>
    The date on which a task is actually finished.
</EPM-HTML>"
4058;RemainingTime;"<EPM-HTML>
    The amount of time remaining to complete a task. It is a predicted value.
    The value is either given as elapsed time or work time, which is defined by
    <i>DurationType</i>.
    <p>
      <b>NOTE:</b> 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.
    </p>
</EPM-HTML>"
4059;Completion;"<EPM-HTML>
      The extent of completion expressed as a ratio or percentage.
      It is a measured value.
</EPM-HTML>"
4066;Name;"<EPM-HTML>
    Optional name for the time definition. 
</EPM-HTML>"
4067;DataOrigin;"<EPM-HTML>
    Specifies the origin of the scheduling time entity. It currently
    differentiates between predicted, simulated, measured, and user defined values.
</EPM-HTML>"
4068;UserDefinedDataOrigin;Value of the data origin if DataOrigin attribute is USERDEFINED.
4070;LagValue;"<EPM-HTML>
    Value of the time lag selected as being either a ratio or a
    time measure.
</EPM-HTML>"
4071;DurationType;"<EPM-HTML>
    The allowed types of task duration that specify the lag time
    measurement (work time or elapsed time).
</EPM-HTML>"
4080;ScheduleWork;"Indicates the total work (e.g. person-hours) allocated to the task on behalf of the resource. 
Note: this is not necessarily the same as the task duration (IfcTaskTime.ScheduleDuration); it may vary according to the resource usage ratio and other resources assigned to the task."
4081;ScheduleUsage;Indicates the amount of the resource used concurrently. For example, 100% means 1 worker, 300% means 3 workers, 50% means half of 1 worker's time for scenarios where multitasking is feasible. If not provided, then the usage ratio is considered to be 100%.
4082;ScheduleStart;Indicates the time when the resource is scheduled to start working.
4083;ScheduleFinish;Indicates the time when the resource is scheduled to finish working.
4084;ScheduleContour;Indicates how a resource should be leveled over time by adjusting the resource usage according to a specified curve.  Standard values include: 'Flat', 'BackLoaded', 'FrontLoaded', 'DoublePeak', 'EarlyPeak', 'LatePeak', 'Bell', and 'Turtle'.  Custom values may specify a custom name or formula.
4085;LevelingDelay;Indicates a delay in the ScheduleStart caused by leveling.
4086;IsOverAllocated;Indicates that the resource is scheduled in excess of its capacity.
4087;StatusTime;"Indicates the date and time for which status values are applicable; particularly completion, actual, and remaining values.  If values are time-phased (the referencing IfcConstructionResource has associated time series values for attributes), then the status values may be determined from such time-phased data as of the StatusTime."
4088;ActualWork;Indicates the actual work performed by the resource as of the StatusTime.
4089;ActualUsage;Indicates the actual amount of the resource used concurrently.
4090;ActualStart;Indicates the time when the resource actually started working.
4091;ActualFinish;Indicates the time when the resource actually finished working.
4092;RemainingWork;Indicates the work remaining to be completed by the resource.
4093;RemainingUsage;
4094;Completion;"Indicates the percent completion of this resource.  If the resource is assigned to a task, then indicates completion of the task on behalf of the resource; if the resource is partitioned into sub-allocations, then indicates overall completion of sub-allocations."
4096;ActualDate;"<EPM-HTML>
     The date on which an event actually occurs. It is a measured value.
</EPM-HTML>
"
4097;EarlyDate;"<EPM-HTML>
     The earliest date on which an event can occur. It is a calculated value.
</EPM-HTML>"
4098;LateDate;"<EPM-HTML>
     The latest date on which an event can occur. It is a calculated value.
</EPM-HTML>"
4099;ScheduleDate;"<EPM-HTML>
    The date on which an event is scheduled to occur. 
    The value might be measured or somehow calculated, which is defined by
    <i>ScheduleDataOrigin</i>.

</EPM-HTML>"
4101;RecurrencePattern;"<EPM-HTML>
    Recurrence pattern that defines a time period, which, if given, is
    valid within the time period defined by
    <i>IfcWorkTime.Start</i> and <i>IfcWorkTime.Finish</i>.
</EPM-HTML>"
4102;Start;"<EPM-HTML>
    Start date of the work time (0:00), that might be further
    restricted by a recurrence pattern.
</EPM-HTML>"
4103;Finish;"<EPM-HTML>
    End date of the work time (24:00), that might be further
    restricted by a recurrence pattern.
</EPM-HTML>"
4105;RecurrenceType;"<EPM-HTML>
    Defines the recurrence type that gives meaning to the used
    attributes and decides about possible attribute
    combinations, i.e. what attributes are needed to fully
    describe the pattern type.
</EPM-HTML>"
4106;DayComponent;"<EPM-HTML>
    The position of the specified day in a month.
</EPM-HTML>
"
4107;WeekdayComponent;"<EPM-HTML>
    The weekday name of the specified day in a week.
</EPM-HTML>"
4108;MonthComponent;"<EPM-HTML>
    The position of the specified month in a year.
</EPM-HTML>
"
4109;Position;"<EPM-HTML>
    The position of the specified component, e.g. the 3rd
    (position=3) Tuesday (weekday component) in a month. A
    negative position value is used to define the last position 
    of the component (-1), the next to last position (-2) etc.
</EPM-HTML>
"
4110;Interval;"<EPM-HTML>
    An interval can be given according to the pattern type. An
    interval value of 2 can for instance every two days, weeks,
    months, years. An empty interval value is regarded as 1. The
    used interval values should be in a reasonable range, e.g.
    not 0 or &lt;0.
</EPM-HTML>"
4111;Occurrences;"<EPM-HTML>
    Defines the number of occurrences of this pattern, e.g. a weekly 
    event might be defined to occur 5 times before it stops.
</EPM-HTML>"
4112;TimePeriods;"<EPM-HTML>
    List of time periods that are defined by a start and end time
    of the recurring element (day). The order of the list should
    reflect the sequence of the time periods.
</EPM-HTML>"
4129;StartTime;"<EPM-HTML>
    Start time of the time period.
</EPM-HTML>"
4130;EndTime;"<EPM-HTML>
    End time of the time period.
</EPM-HTML>"
4132;Recurrance;
4141;PointOnRelatingElement;Point at which the connected object is aligned at the relating element, given in the LCS of the relating element.
4184;PlacementRefDirection;"<EPM-HTML>
Reference to either an explicit direction, or a second grid axis intersection, which defines the orientation of the grid placement.
<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE  The select of an explict direction has been added.
</font></small>
</blockquote>
</EPM-HTML>"
4188;PlacesObject;"<EPM-HTML>
The <i>IfcObjectPlacement</i> shall be used to provide a placement and 
an object coordinate system for <strike>a single</strike> <font color=""#0000ff"">
one or many instances of <i>IfcProduct</i>. If an <i>IfcObjectPlacement</i> is 
shared by many instances of <i>IfcProduct</i> it does not apply a semantic
meaning of being a shared property that needs to be maintained. Using 
the same instance of <i>IfcObjectPlacement</i> could simply be used to
reduce exchange file size.</font>
<blockquote>
 <small><font color=""#ff0000"">
   IFC2x3 CHANGE&nbsp; New inverse attribute.
</font></small><br>
 <small><font color=""#ff0000"">
   IFC2x4 CHANGE&nbsp; The cardinality has changed to 1..n to allow reuse of instances of <i>IfcObjectPlacement</i> as placement object in one to many products.
 </font></small>
</blockquote>
</EPM-HTML>"
4189;ReferencedByPlacements;Placements that are given relative to this placement of an object.
4191;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.
"
4192;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.
4200;Name;"<EPM-HTML>
Name of the material. 
<blockquote>
  <small>
EXAMPLE A view definition may require <i>Material.Name</i> to uniquely specify e.g. concrete or steel grade, in which case the attribute Material.Category could take the value 'Concrete' or 'Steel'. <br>
  </small>
  <small>
NOTE Material grade may have diffenrent meaning in different view definitions, e.g. strength grade for structural design and analysis, or visible appearance grade in architectural application. Also, more elaborate material grade definition may be associated as classification via inverse attribute <i>HasExternalReferences</i>.
  </small>
</blockquote>
</EPM-HTML>"
4201;Description;"<EPM-HTML>
Definition of the material in more descriptive terms than given by attributes <i>Name</i> or <i>Category</i>.
<blockquote><p>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The attribute has been added at the end of attribute list.
    </font>
  </small>
</p></blockquote>
</EPM-HTML>"
4202;Category;"<EPM-HTML>
Definition of the category (group or type) of material, in more general terms than given by attribute <i>Name</i>.  
<blockquote>
  <small>
EXAMPLE A view definition may require each <i>Material.Name</i> to be unique, e.g. for each concrete or steel grade used in a project, in which case <i>Material.Category</i> could take the values 'Concrete' or 'Steel'.<br>
  </small>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The attribute has been added at the end of attribute list.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4203;HasRepresentation;"<EPM-HTML>
Reference to the <i>IfcMaterialDefinitionRepresentation</i> that provides presentation information to a representation common to this material in style definitions.
  <blockquote>
<small><font color=""#ff0000"">IFC2x Edition 3 CHANGE&nbsp; The inverse attribute <i>HasRepresentation</i> has been added.</font></small>
</blockquote>
</EPM-HTML>"
4204;IsRelatedWith;"<EPM-HTML>
Reference to a material relationship indicating that this material is a part (or constituent) in a material composite.
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The inverse attribute has been added.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4205;RelatesTo;"<EPM-HTML>
Reference to a material relationship indicating that this material composite has parts (or contituents).
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The inverse attribute has been added.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4214;AssociatedTo;"<EPM-HTML>
Use of the <i>IfcMaterialDefinition</i> subtypes within the material association of an element occurrence or element type. The association is established by the <i>IfcRelAssociatesMaterial</i> relationship.
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The inverse attribute has been added.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4215;HasExternalReferences;"<EPM-HTML>
Reference to external references, e.g. library, classification, or document information, that are associated to the material.
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The inverse attribute has been added.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4216;HasProperties;"<EPM-HTML>
Material properties assigned to instances of subtypes of <i>IfcMaterialDefinition</i>.
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The inverse attribute has been added.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4219;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.
4220;LayerThickness;"<EPM-HTML>
The thickness of the material layer. The dimension is measured along the positive MlsDirection as specified in <i>IfcMaterialLayerSet</i> (that is mapped to AXIS-2, as specified in <i>IfcMaterialLayerSetUsage</i> for element occurrences supporting <i>IfcMaterialLayerSetUsage</i>.
<blockquote><p>
  <small>
    <font color=""#ff0000"">NOTE&nbsp; The attribute value can be 0. for material thicknesses very close to zero, such as for a membrane. Material layers with thickess 0. shall not be rendered in the geometric representation.<br><br>
    </font>
  </small>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The attribute datatype has been changed to <i>IfcNonNegativeLengthMeasure</i> allowing for 0. as thickness.
    </font>
  </small>
</p></blockquote>

</EPM-HTML>"
4221;IsVentilated;"<EPM-HTML>
Indication of whether the material layer represents an air layer (or cavity). 
<ul>
  <li>set to TRUE if the material layer is an air gap and provides air exchange from the layer to the outside air.</li>
  <li>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).</li>
  <li>set to FALSE if the material layer is a solid material layer (the default).</li> 
</ul>
</EPM-HTML>"
4222;Name;The name by which the material layer is known.
4223;Description;Definition of the material layer in more descriptive terms than given by attributes Name or Category.
4224;Category;Category of the material layer, e.g. the role it has in the layer set it belongs to (such as 'load bearing', 'thermal insulation' etc.).
4225;Priority;"<EPM-HTML>
The relative priority of the layer, expressed as ratio measure, normalised to 0..1. Controls how layers intersect in connections and corners of building elements: a layer from one element protrudes into (i.e. displaces) a layer from another element in a joint of these elements if the former element's layer has higher priority than the latter. The priorty value for a material layer in an element has to be set and maintained by software applications, in relation to the material layers in connected elements. The usage has to be further specified for each element, especially to avoid simultanious use with <i>IfcLayerOffset</i>.
</EPM-HTML>"
4226;ToMaterialLayerSet;Reference to the material layer set in which the material layer is included.
4228;OffsetDirection;"<EPM-HTML>
Orientation of the offset; shall be perpendicular to the parent layer set direction.
</EPM-HTML>
"
4229;OffsetValues;"<EPM-HTML>
The numerical value of layer offset, in the direction of the axis assigned by the attribute <i>OffsetDirection</i>. The <i>OffsetValues[1]</i> identifies the offset from the lower position along the axis direction (normally the start of the standard extrusion), the <i>OffsetValues[2]</i> identifies the offset from the upper position along the axis direction (normally the end of the standard extrusion),
</EPM-HTML>"
4235;MaterialLayers;Identification of the layers from which the material layer set is composed.
4236;LayerSetName;The name by which the material layer set is known.
4237;Description;"<EPM-HTML>
Definition of the material layer set in descriptive terms.
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The attribute has been added at the end of attribute list.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4238;TotalThickness;<EPM-HTML>Total thickness of the material layer set is derived from the function <i>IfcMlsTotalThickness.</i></EPM-HTML>
4240;Name;"<EPM-HTML>
The name by which the material profile set is known.
</EPM-HTML>"
4241;Description;Definition of the material profile set in descriptive terms.
4242;MaterialProfiles;"<EPM-HTML>
Identification of the profiles from which the material profile set is composed.
</EPM-HTML>"
4243;CompositeProfile;"<EPM-HTML>
Reference to the composite profile definition for which this material profile set associates material to each of its individual profile. 

<blockquote><small>NOTE &nbsp; 
The referenced <i>IfcCompositeProfileDef</i> instance shall be composed of all of the <i>IfcProfileDef</i> instances which are used via the MaterialProfiles list in the current <i>IfcMaterialProfileSet</i> .
</small>
</blockquote>

</EPM-HTML>"
4246;Name;The name by which the material profile is known.
4247;Description;Definition of the material profile in descriptive terms.
4248;Material;Optional reference to the material from which the profile is constructed.
4249;Profile;Identification of the profile for which this material profile is associating material.
4250;Priority;"<EPM-HTML>
The relative priority of the profile, expressed as ratio measure, normalised to 0..1. Controls how profiles intersect in connections and corners of building elements: a profile from one element protrudes into (i.e. displaces) a profile from another element in a joint of these elements if the former element's profile has higher priority than the latter. The priorty value for a material profile in an element has to be set and maintained by software applications, in relation to the material profiles in connected elements.
</EPM-HTML>"
4251;Category;Category of the material profile, e.g. the role it has in the profile set it belongs to.
4252;ToMaterialProfileSet;Material profile set in which this material profile is included.
4254;OffsetValues;"<EPM-HTML>
The numerical value of profile offset, in the direction of the axis direction - always AXIS1 i.e. the axis along the extrusion path. The <i>OffsetValues[1]</i> identifies the offset from the lower position along the axis direction (normally the start of the standard extrusion), the <i>OffsetValues[2]</i> identifies the offset from the upper position along the axis direction (normally the end of the standard extrusion),
</EPM-HTML>"
4256;Name;"<EPM-HTML>
The name by which the constituent set is known.
</EPM-HTML>"
4257;Description;"<EPM-HTML>
Definition of the material constituent set in descriptive terms.
</EPM-HTML>"
4258;MaterialConstituents;"<EPM-HTML>
Identification of the constituents from which the material constituent set is composed.
</EPM-HTML>"
4260;Name;"<EPM-HTML>
The name by which the material constituent is known.
</EPM-HTML>"
4261;Description;"<EPM-HTML>
Definition of the material constituent in descriptive terms.
</EPM-HTML>"
4262;Material;"<EPM-HTML>
Reference to the material from which the constituent is constructed.
</EPM-HTML>"
4263;Fraction;"<EPM-HTML>
Optional provision of a fraction of the total amount (volume or weight) that applies to the <i>IfcMaterialConstituentSet</i> that is contributed by this <i>IfcMaterialConstituent</i>.
</EPM-HTML>"
4264;Category;"<EPM-HTML>
Category of the material constituent, e.g. the role it has in the constituent set it belongs to.
</EPM-HTML>"
4265;ToMaterialConstituentSet;"<EPM-HTML>
Material constituent set in which this material constituent is included.
</EPM-HTML>"
4267;RelatingMaterial;Reference to the relating material (the composite).
4268;RelatedMaterials;Reference to related materials (as constituents of composite material).
4269;Expression;The amount of related material in the whole (composite material or material set). Expressed as proportion (percentage) of weight or volume, or as any other appropriate value.
4272;Name;"<EPM-HTML>
The name given to the set of extended properties. 
</EPM-HTML>"
4273;Description;"<EPM-HTML>
Description for the set of material properties.
</EPM-HTML>"
4274;Material;"<EPM-HTML>
Reference to the material definition to which the set of properties is assigned.
<blockquote>
  <small>
    <font color=""#ff0000"">
      IFC2x4 CHANGE  The datatype has been changed to supertype <i>IfcMaterialDefinition</i>.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4276;Properties;"<EPM-HTML>
The set of material properties provided for this material definition.
</EPM-HTML>"
4278;MaterialClassifications;The material classifications identifying the type of material.
4279;ClassifiedMaterial;Material being classified.
4281;ForLayerSet;"<EPM-HTML>
The <i>IfcMaterialLayerSet</i> set to which the usage is applied.
</EPM-HTML>"
4282;LayerSetDirection;"<EPM-HTML>
Orientation of the material 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).

<blockquote>
  <small>NOTE&nbsp; the <i>LayerSetDirection</i> for <i>IfcWallStandardCase</i> shall be AXIS2 (i.e. the y-axis) and for <i>IfcSlabStandardCase</i> and <i>IfcPlateStandardCase</i> it shall be AXIS3 (i.e. the z-axis).
  </small>
</blockquote>

Whether the material layers of the set being used shall 'grow' into the positive or negative direction of the given axis, shall be deifned by <i>DirectionSense</i> attribute.
</EPM-HTML>"
4283;DirectionSense;"<EPM-HTML>
Denotion whether the material layer set is oriented in positive or negative sense along the specified axis (defined by LayerSetDirection). ""Positive"" means that the consecutive layers (the <i>IfcMaterialLayer</i> instances in the list of <i> IfcMaterialLayerSet.MaterialLayers</i>) are placed face-by-face in the direction of the positive axis as established by LayerSetDirection: for AXIS2 it would be in +y, for AXIS3 it would be +z. ""Negative"" means that the layers are placed face-by-face in the direction of the negative LayerSetDirection. In both cases,  starting at the material layer set base line.
<blockquote><small>NOTE&nbsp; the material layer set base line (MlsBase) is located by OffsetFromReferenceLine, and may be on the positive or negative side of the element reference line (or plane); positive or negative for MlsBase placement does not depend on the DirectionSense attribute, but on the relevant element axis.</small></blockquote>
</EPM-HTML>"
4284;OffsetFromReferenceLine;"<EPM-HTML>
Offset of the material layer set base line (MlsBase) from reference geometry (line or plane) of element. The offset can be positive or negative, unless restricted for a particular building element type in its use definition or by implementer agreement. A positive value means, that the MlsBase is placed on the positive side of the reference line or plane, on the axis established by LayerSetDirection (in case of AXIS2 into the direction of +y, or in case of AXIS2 into the direction of +z). A negative value means that the MlsBase is placed on the negative side, as established by LayerSetDirection (in case of AXIS2 into the direction of -y). <blockquote><small>NOTE&nbsp; the positive or negative sign in the offset only affects the MlsBase placement, it does not have any effect on the application of DirectionSense for orientation of the material layers; also DirectionSense does not change the MlsBase placement.
</small></blockquote>
</EPM-HTML>
"
4285;ReferenceExtent;"EPM-HTML>
Extent of the extrusion of the elements body shape representation to which the <em>IfcMaterialLayerSetUsage</em> applies. It is used as the reference value for the upper <em>OffsetValues[2]</em> provided by the <em>IfcMaterialLayerSetWithOffsets</em> subtype for included material layers.

<blockquote>
  <p>
    <span style=""font-size:smaller;color:red"">
      IFC2x4 CHANGE&nbsp; New attribute added to the end of attribute list.
    </span>
  </p>
  <p>
    <span style=""font-size:smaller;color:blue"">
      NOTE 1&nbsp; The attribute <em>ReferenceExtent</em> shall be asserted, if an <em>IfcMaterialLayerSetWithOffsets</em> is included in the <em>ForLayerSet.MaterialLayers</em> list of maerial layers.
    </span><br>
    <span style=""font-size:smaller;color:blue"">
      NOTE 2&nbsp; The <em>ReferenceExtent</em> for <em>IfcWallStandardCase</em> is the reference height starting at z=0 being the XY plane of the object coordinate system.
    </span>
  </p>
</blockquote>

</EPM-HTML>"
4289;AssociatedTo;"<EPM-HTML>
Use of the <i>IfcMaterialUsageDefinition</i> subtypes within the material association of an element occurrence. The association is established by the <i>IfcRelAssociatesMaterial</i> relationship.
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The inverse attribute has been added.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4292;ForProfileSet;"<EPM-HTML>
The <i>IfcMaterialProfileSet</i> set to which the usage is applied.
</EPM-HTML>"
4293;CardinalPoint;"<EPM-HTML>
Index reference to a significant point in the section profile. Describes how the section is aligned relative to the (longitudinal) axis of the member it is associated with. This parametric specification of profile alignment can be provided redundantly to the explicit alignment defined by ForProfileSet.MaterialProfiles[*].Profile.
</EPM-HTML>"
4294;ReferenceExtent;"EPM-HTML>
Extent of the extrusion of the elements body shape representation to which the <em>IfcMaterialProfileSetUsage</em> applies. It is used as the reference value for the upper <em>OffsetValues[2]</em> provided by the <em>IfcMaterialProfileSetWithOffsets</em> subtype for included material profiles.

<blockquote>
  <p>
    <span style=""font-size:smaller;color:blue"">
      NOTE 1&nbsp; The attribute <em>ReferenceExtent</em> shall be asserted, if an <em>IfcMaterialProfileSetWithOffsets</em> is included in the <em>ForProfileSet.MaterialProfiles</em> list of maerial layers.
    </span><br>
    <span style=""font-size:smaller;color:blue"">
      NOTE 2&nbsp; The <em>ReferenceExtent</em> for <em>IfcBeamStandardCase</em>, <em>IfcColumnStandardCase</em>, and <em>IfcMemberStandardCase</em> is the reference length starting at z=0 being the XY plane of the object coordinate system.
    </span>
  </p>
</blockquote>

</EPM-HTML>"
4296;ForProfileEndSet;"<EPM-HTML>
The second <i>IfcMaterialProfileSet</i> set to which the usage is applied.
</EPM-HTML>"
4297;CardinalEndPoint;"<EPM-HTML>
Index reference to a significant point in the second section profile. Describes how this section is aligned relative to the axis of the member it is associated with. This parametric specification of profile alignment can be provided redundantly to the explicit alignment defined by ForProfileSet.MaterialProfiles[*].Profile.
</EPM-HTML>"
4305;Materials;Materials used in a composition of substances.
4368;Elements;The group of units and their exponents that define the derived unit.
4369;UnitType;Name of the derived unit chosen from an enumeration of derived unit types for use in IFC models.
4370;UserDefinedType;
4371;Dimensions;"Dimensional exponents derived using the function IfcDerivedDimensionalExponents using (SELF) as the input value.
"
4375;Unit;The fixed quantity which is used as the mathematical factor.
4376;Exponent;The power that is applied to the unit attribute.
4381;Dimensions;The dimensional exponents of the SI base units by which the named unit is defined.
4382;UnitType;The type of the unit.
4385;Name;The word, or group of words, by which the context dependent unit is referred to.
4386;HasExternalReference;"<EPM-HTML>
Reference to external information, e.g. library, classification, or document information, which is associated with the context dependent unit.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE New inverse attribute.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4390;Name;The word, or group of words, by which the conversion based unit is referred to.
4391;ConversionFactor;The physical quantity from which the converted unit is derived.
4392;HasExternalReference;"<EPM-HTML>
Reference to external information, e.g. library, classification, or document information, which is associated with the conversion-based unit.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE New inverse attribute.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
4394;ConversionOffset;"<EPM-HTML>

A positive or negative offset to add after the inherited <i>ConversionFactor</i> was applied.

</EPM-HTML>
"
4396;ValueComponent;The value of the physical quantity when expressed in the specified units.
4397;UnitComponent;The unit in which the physical quantity is expressed.
4568;Prefix;The SI Prefix for defining decimal multiples and submultiples of the unit.
4569;Name;"<EPM-HTML>

The word, or group of words, by which the SI unit is referred to.

<blockquote><font size=""-1"">NOTE&nbsp; Even though the SI system's base unit for mass is kilogram, the <i>IfcSIUnit</i> for mass is gram if no <i>Prefix</i> is asserted.</font></blockquote>

</EPM-HTML>
"
4570;Dimensions;"<EPM-HTML>
The dimensional exponents of SI units are derived by function <I>IfcDimensionsForSiUnit</I>.
</EPM-HTML>"
4620;LengthExponent;The power of the length base quantity.
4621;MassExponent;The power of the mass base quantity.
4622;TimeExponent;The power of the time base quantity.
4623;ElectricCurrentExponent;The power of the electric current base quantity.
4624;ThermodynamicTemperatureExponent;The power of the thermodynamic temperature base quantity.
4625;AmountOfSubstanceExponent;The power of the amount of substance base quantity.
4626;LuminousIntensityExponent;The power of the luminous intensity base quantity.
4710;Currency;"<EPM-HTML>

Code or name of the currency.  Permissible values are the three-letter alphabetic currency codes as per <a target=""_top"" href=""http://www.iso.org/iso/support/faqs/faqs_widely_used_standards/widely_used_standards_other/currency_codes/currency_codes_list-1.htm"">ISO 4217</a>, for example CNY, EUR, GBP, JPY, USD.

</EPM-HTML>"
4712;Units;Units to be included within a unit assignment.
4720;HatchLineAppearance;The curve style of the hatching lines. Any curve style pattern shall start at the origin of each hatch line.
4721;StartOfNextHatchLine;"<EPM-HTML>A repetition factor that determines the distance between adjacent hatch lines.
  <blockquote><small><color=""#ff0000"">
IFC2x Edition 3 CHANGE&nbsp; The attribute type of <i>StartOfNextHatchLine</i> has changed to a SELECT of <i>IfcPositiveLengthMeasure</i> (new) and <i>IfcOneDirectionRepeatFactor</i>.</font></small></blockquote>
</EPM-HTML>
"
4722;PointOfReferenceHatchLine;"<EPM-HTML>
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.<br>
If not given the reference hatch lines goes through the origin of the (virtual) hatching coordinate system.
  <blockquote><small><font color=""#ff0000"">
IFC2x Edition 3 CHANGE&nbsp; The usage of the attribute <i>PointOfReferenceHatchLine</i> has changed to not provide the Cartesian point which is the origin for mapping, but to provide an offset to the origin for the mapping. The attribute has been made OPTIONAL.
  </font></small></blockquote>
</EPM-HTML>"
4723;PatternStart;"<EPM-HTML>
A distance along the reference hatch line which is the start point for the curve style font pattern of the reference hatch line.<br>
If not given, the start point of the curve style font pattern is at the (virtual) hatching coordinate system.
  <blockquote><small><font color=""#ff0000"">
IFC2x Edition 2 Addendum 2 CHANGE The attribute <i>PatternStart</i> has been made OPTIONAL.</font></small></blockquote>
</EPM-HTML>"
4724;HatchLineAngle;A plane angle measure determining the direction of the parallel hatching lines.
4729;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.
4730;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.
4731;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.
4739;Name;"<EPM-HTML>
Name of the presentation style.
</EPM-HTML>"
4741;TextCharacterAppearance;"<EPM-HTML>
A character style to be used for presented text.
</EPM-HTML>"
4742;TextStyle;"<EPM-HTML>
The style applied to the text block for its visual appearance.</br>
It defines the text block characteristics, either for vector based or monospace text fonts (see select item <i>IfcTextStyleWithBoxCharacteristics</i>), or for true type text fonts (see select item <i>IfcTextStyleTextModel</i>.
  <blockquote><small><font color=""#0000ff"">
IFC2x Edition 3 CHANGE&nbsp; The <i>attribute <i>TextBlockStyle</i> has been changed from SET[1:?] to a non-aggregated optional, it has been renamed from TextStyles.
  </font></small></blockquote>
</EPM-HTML>"
4743;TextFontStyle;"<EPM-HTML>
The style applied to the text font for its visual appearance.</br>
It defines the font family, font style, weight and size.
  <blockquote><small><font color=""#ff0000"">
IFC2x Edition 2 Addendum 2 CHANGE The attribute <i>TextFontStyle</i> is a new attribute attached to <i>IfcTextStyle</i>.
  </font></small></blockquote>
</EPM-HTML>"
4747;Colour;"<EPM-HTML>
This property describes the text color of an element (often referred to as the foreground color).
</EPM-HTML>"
4748;BackgroundColour;"<EPM-HTML>
This property sets the background color of an element.
</EPM-HTML>"
4757;BoxHeight;It is the height scaling factor in the definition of a character glyph.
4758;BoxWidth;It is the width scaling factor in the definition of a character glyph.
4759;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.
4760;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.
4761;CharacterSpacing;The distance between the character boxes of adjacent characters.
4770;TextIndent;"<EPM-HTML>
The property specifies the indentation that appears before the first formatted line.
  <blockquote> <small>NOTE&nbsp; It has been introduced for later compliance to full CSS1 support.</small></blockquote>
</EPM-HTML>"
4771;TextAlign;"<EPM-HTML>
This property describes how text is aligned horizontally within the element. The actual justification algorithm used is dependent on the rendering algorithm.
</EPM-HTML>"
4772;TextDecoration;"<EPM-HTML>
This property describes decorations that are added to the text of an element.
</EPM-HTML>"
4773;LetterSpacing;"<EPM-HTML>
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).
  <blockquote> <small>NOTE&nbsp; The following values are allowed, <i>IfcDescriptiveMeasure</i> with value='normal', or <i>IfcLengthMeasure<i>, the length unit is globally defined at <i>IfcUnitAssignment</i>.</small></blockquote>
</EPM-HTML>"
4774;WordSpacing;"<EPM-HTML>
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).
  <blockquote> <small>NOTE&nbsp; It has been introduced for later compliance to full CSS1 support.</small></blockquote>
</EPM-HTML>"
4775;TextTransform;"<EPM-HTML>
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.
  <blockquote> <small>NOTE&nbsp; It has been introduced for later compliance to full CSS1 support.</small></blockquote>
</EPM-HTML>"
4776;LineHeight;"<EPM-HTML>
The property sets the distance between two adjacent lines' baselines.<br>
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.
  <blockquote> <small>NOTE&nbsp; The following values are allowed:<br> <i>IfcDescriptiveMeasure</i> with value='normal', or <br>
<i>IfcLengthMeasure<i>, with non-negative values, the length unit is globally defined at <i>IfcUnitAssignment</i>, or <br><i>IfcRatioMeasure</i>.</small></blockquote>
</EPM-HTML>"
4784;FillStyles;The set of fill area styles to use in presenting visible curve segments, annotation fill areas or surfaces.
4794;TilingPattern;A two direction repeat factor defining the shape and relative positioning of the tiles.
4795;Tiles;A set of constituents of the tile.
4796;TilingScale;The scale factor applied to each tile as it is placed in the annotation fill area.
4799;RepeatFactor;A vector which specifies the relative positioning of hatch lines.
4801;SecondRepeatFactor;A vector which specifies the relative positioning of tiles in the second direction.
4805;Symbol;"<EPM-HTML>
A styled item that is used as the annotation symbol for tiling the filled area.
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE  The data type has been changed to <i>IfcStyleItem</i>.</font><br>
  </small>
  <small>
    <font color=""#ff0000"">NOTE  Only <i>IfcStyleItem</i>'s that refer to a compatible geometric representation item and presentation style shall be used.</font>
  </small>
</blockquote>
</EPM-HTML>"
4807;Item;"<EPM-HTML>
A geometric representation item to which the style is assigned.
  <blockquote> <font size=""-1"" color=""#0000ff"">
IFC2x Edition 2 Addendum 2 CHANGE The attribute <i>Item</i> has been made optional. Upward compatibility for file based exchange is guaranteed.
  </font></blockquote>
</EPM-HTML>"
4808;Styles;"<EPM-HTML>
Representation styles which are assigned, either to an geometric representation item, or to a material definition.
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE  The data type has been changed to <i>IfcStyleAssignmentSelect</i> with upward compatibility 
for file based exchange.</font><br>
  </small>
  <small>
    <font color=""#ff0000"">NOTE  Only the select item <i>IfcPresentationStyle</i> shall be used from IFC2x4 onwards, the <i>IfcPresentationStyleAssignment</i> has been deprecated.</font>
  </small>
</blockquote>
</EPM-HTML>"
4809;Name;The word, or group of words, by which the styled item is referred to.
4815;Styles;A set of presentation styles that are assigned to styled items.
4826;StyleOfSymbol;The style applied to the symbol for its visual appearance.
4830;Side;An indication of which side of the surface to apply the style.
4831;Styles;A collection of different surface styles.
4849;SurfaceColour;"The colour used to render the surface. The surface colour for visualisation is defined by specifying the intensity of red, green and blue.
"
4851;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.
"
4852;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.
"
4853;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.
"
4854;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.
"
4855;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.
"
4856;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.

"
4857;SpecularHighlight;"The exponent or roughness part of the specular reflectance.
"
4858;ReflectanceMethod;"Identifies the predefined types of reflectance method from which the method required may be set.
"
4880;DiffuseTransmissionColour;"<EPM-HTML>
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.
<blockquote><small>The factor can be measured physically and has three ratios for the red, green and blue part of the light.
</small></blockquote>
</EPM-HTML>"
4881;DiffuseReflectionColour;"<EPM-HTML>
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. 
<blockquote><small>The factor can be measured physically and has three ratios for the red, green and blue part of the light.
</small></blockquote>
</EPM-HTML>"
4882;TransmissionColour;"<EPM-HTML>
Describes how the light falling on a body is totally or partially transmitted. 
<blockquote><small>The factor can be measured physically and has three ratios for the red, green and blue part of the light.
</small></blockquote>
</EPM-HTML>"
4883;ReflectanceColour;"<EPM-HTML>
A coefficient that determines the extent that the light falling onto a surface is fully or partially reflected. 
<blockquote><small>The factor can be measured physically and has three ratios for the red, green and blue part of the light.
</small></blockquote>
</EPM-HTML>"
4885;Textures;"<EPM-HTML>
The textures applied to the surface. In case of more than one surface texture is included, the <em>IfcSurfaceStyleWithTexture</em> defines a multi texture.
</EMP-HTML>"
4890;RepeatS;"<EPM-HTML>
The <em>RepeatS</em> field specifies how the texture wraps in the S direction. If <em>RepeatS</em> 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 <em>RepeatS</em> is FALSE, the texture coordinates are clamped in the S direction to lie within the [0.0, 1.0] range.
<br /> 
</EPM-HTML>"
4891;RepeatT;"<EPM-HTML>
The <em>RepeatT</em> field specifies how the texture wraps in the T direction. If <em>RepeatT</em> 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 <em>RepeatT</em> is FALSE, the texture coordinates are clamped in the T direction to lie within the [0.0, 1.0] range. 
<br />
</EPM-HTML>"
4892;Mode;"<EPM-HTML>
The <em>Mode</em> attribute is provided to control the appearance of a multi textures. The mode then controls the type of blending operation. The mode includes a MODULATE for a lit appearance, a REPLACE for a unlit appearance, and variations of the two.
<blockquote>
  <p>
    <span ""style:font-size:smaller"">NOTE&nbsp; The applicable values for the <em>Mode</em> attribute are determined by view definitions or implementer agreements. It is recommended to use the modes described in ISO/IES 19775-1.2:2008 X3D Architecture and base components Edition 2, Part 1. See <a href=""http://www.web3d.org/x3d/specifications/ISO-IEC-19775-1.2-X3D-AbstractSpecification/Part01/components/texturing.html#MultiTexture"">18.4.3 MultiTexture</a> for recommended values.</span>
  </p>
  <p>
    <span ""style:font-size:smaller;color:red"">IFC2x4 CHANGE&nbsp; New attribute replacing previous TextureType.</span>
  </p>
</blockquote>
</EPM-HTML>"
4893;TextureTransform;"<EPM-HTML>
The <em>TextureTransform</i> defines a 2D transformation that is applied to the texture coordinates. It affects the way texture coordinates are applied to the surfaces of geometric representation itesm. The 2D transformation supports changes to the size, orientation, and position of textures on shapes. 
<blockquote>
  <p>
    <span style:""font-size:smaller"">Mirroring is not allowed to be used in the <em>IfcCarteesianTransformationOperator</em></span>
  </p>
</blockquote>
</EPM-HTML>"
4894;Parameter;"<EPM-HTML>
The <em>Parameter</em> attribute is provided to control the appearance of a multi textures. The applicable parameters depend on the value of the <em>Mode</em> attribute.
<blockquote>
  <p>
    <span ""style:font-size:smaller"">NOTE&nbsp; The applicable values for the list of <em>Parameter</em> attributes are determined by view definitions or implementer agreements. It is recommended to use the source and the function fields described in ISO/IES 19775-1.2:2008 X3D Architecture and base components Edition 2, Part 1. See <a href=""http://www.web3d.org/x3d/specifications/ISO-IEC-19775-1.2-X3D-AbstractSpecification/Part01/components/texturing.html#MultiTexture"">18.4.3 MultiTexture</a> for recommended values.<br />
By convention, <em>Parameter[1]</em> shall then hold the source value, <em>Parameter[2]</em> the function value, <em>Parameter[3]</em> the base RGB color for select operations, and <em>Parameter[4]</em> the alpha value for select operations.</span>
  </p>
  <p>
    <span ""style:font-size:smaller;color:red"">IFC2x4 CHANGE&nbsp; New attribute added at the end of the attribute list.</span>
  </p>
</blockquote>
</EPM-HTML>"
4895;MappedBy;"<EPM-HTML>
Texture coordinates, either provided by a corresponding list of texture vertices to vertex-based geometric items or by a texture coordinate generator, that applies the surface texture to the surfaces of the geometric items.
<blackquote>
  <p>
    <span ""style:font-size:smaller;color:red"">IFC2x4 CHANGE&nbsp; New attribute added at the end of the attribute list.</span>
  </p>
</blockquote>
</EPM-HTML>"
4896;UsedInStyles;
4898;Width;"<EPM-HTML>
The number of pixels in width (S) direction.
</EPM-HTML>"
4899;Height;"<EPM-HTML>
The number of pixels in height (T) direction.
</EPM-HTML>"
4900;ColourComponents;"<EPM-HTML>Indication whether the pixel values contain a 1, 2, 3, or 4 colour component.
</EPM-HTML>"
4901;Pixel;"<EPM-HTML>
Flat list of hexadecimal values, each describing one pixel by 1, 2, 3, or 4 components.
<blockquote><small><font color""#ff0000"">
IFC2x Edition 3 CHANGE&nbsp; The data type has been changed from STRING to BINARY.
</font></small></blockquote>
</EPM-HTML>"
4908;URLReference;"<EPM-HTML>
Location, provided as an URI, at which the image texture is electronically published.
</EPM-HTML>"
4912;RasterFormat;"<EPM-HTML>
The format of the <i>RasterCode</i> often using a compression.
</EPM-HTML>"
4913;RasterCode;"<EPM-HTML>
Blob, given as a single binary, to capture the texture within one popular file (compression) format. The file format is provided by the <i>RasterFormat</i> attribute.
</EPM-HTML>"
4917;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
4918;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.
4926;Name;Name that may be assigned with the curve font.
4927;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.
4929;VisibleSegmentLength;"<EPM-HTML>
The length of the visible segment in the pattern definition.
<blockquote><small>
  NOTE&nbsp; For a visible segment representing a point, the value 0. should be assigned.<br>
<font color=""#FF0000"">
  IFC2x Edition 3 CHANGE&nbsp; The datatype has been changed to IfcLengthMeasure with upward compatibility for file-based exchange.
</font></small></blockquote>
</EPM-HTML>"
4930;InvisibleSegmentLength;The length of the invisible segment in the pattern definition.
4933;Name;Name that may be assigned with the scaling of a curve font.
4934;CurveFont;The curve font to be scaled.
4935;CurveFontScaling;The scale factor.
4943;Literal;"<EPM-HTML>
The text literal to be presented.
</EPM-HTML>"
4944;Placement;"<EPM-HTML>
An <i>IfcAxis2Placement</i> that determines the placement and orientation of the presented string.
<blockquote><small>When used with a text style based on <i>IfcTextStyleWithBoxCharacteristics</i> then the y-axis is taken as the reference direction for the box rotation angle and the box slant angle.
</small></blockquote>
</EPM-HTML>"
4945;Path;"<EPM-HTML>
The writing direction of the text literal.
</EPM-HTML>"
4947;OuterBoundary;"<EPM-HTML>
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.
<blockquote><small><font color=""#ff0000"">
  IFC2x Edition 3 CHANGE&nbsp; The two new attributes <i>OuterBoundary</i> and <i>InnerBoundaries</i> replace the old single attribute Boundaries.
</font></small></blockquote>
</EPM-HTML>"
4948;InnerBoundaries;"<EPM-HTML>
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.
<blockquote><small><font color=""#ff0000"">
  IFC2x Edition 3 CHANGE&nbsp; The two new attributes <i>OuterBoundary</i> and <i>InnerBoundaries</i> replace the old single attribute Boundaries.
</font></small></blockquote>
</EPM-HTML>"
4950;Definition;An implicit description of the symbol, either predefined or externally defined.
5003;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.
"
5004;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).
"
5006;Position;"The position of the light source. It is used to orientate the light distribution curves.
"
5007;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.
"
5008;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).
"
5009;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.
"
5010;LightEmissionSource;"Identifies the types of light emitter from which the type required may be set.
"
5011;LightDistributionDataSource;"The data source from which light distribution data is obtained.
"
5028;LightDistributionCurve;Standardized  light distribution curve used to define the luminous intensity of the light in all directions.
5029;DistributionData;"<EPM-HTML>
<P>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 &#946; or &#947; angles) and the according luminous intensity distribution measures.
</P>
</EPM-HTML>"
5036;MainPlaneAngle;The main plane angle (A, B or C angles, according to the light distribution curve chosen).
5037;SecondaryPlaneAngle;"<EPM-HTML>
<P>The list of secondary plane angles (the &#945;, &#946; or &#947; angles) according to the light distribution curve chosen.
</P>
<BLOCKQUOTE>NOTE: The <I>SecondaryPlaneAngle</I> and <I>LuminousIntensity</I> lists are corresponding lists.
</BLOCKQUOTE>
</EPM-HTML>"
5038;LuminousIntensity;The luminous intensity distribution measure for this pair of main and secondary plane angles according to the light distribution curve chosen.
5041;Name;Name of the layer.
5042;Description;Additional description of the layer.
5043;AssignedItems;The set of layered items, which are assigned to this layer.
5044;Identifier;An (internal) identifier assigned to the layer.
5047;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.
5048;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.
5049;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.
5050;LayerStyles;"<EPM-HTML>
Assignment of presentation styles to the layer to provide a default style for representation items.
<blockquote>
  <small>
NOTE&nbsp; In most cases the assignment of styles to a layer is restricted to an <em>IfcCurveStyle</em> representing the layer curve colour, layer curve thickness, and layer curve type.
  </small>
  <small>
IFC2x4 CHANGE&nbsp; The data type has been changed from <em>IfcPresentationStyleSelect</em> (now deprecated) to <em>IfcPresentationStyle</em>.
  </small>
</blockquote>
</EPM-HTML>"
5067;Position;"Position coordinate system of the parameterized profile definition. If unspecified, no translation and no rotation is applied.
"
5074;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.
5075;ProfileName;"<EPM-HTML>

Human-readable name of the profile, for example according to a standard profile table. As noted above, machine-readable standardized profile designations should be provided in <i>IfcExternalReference.ItemReference</i>.

</EPM-HTML>
"
5076;HasExternalReference;"<EPM-HTML>
Reference to external information, e.g. library, classification, or document information, which is associated with the profile.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE New inverse attribute.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
5077;HasProperties;"<EPM-HTML>
Additional properties of the profile, for example mechanical properties.
<blockquote>
  <small>
    <font color=""#ff0000"">
IFC2x4 CHANGE New inverse attribute.
    </font>
  </small>
</blockquote>
</EPM-HTML>"
5080;Curve;Open bounded curve defining the profile.
5084;Thickness;"<EPM-HTML>
Constant thickness applied along the center line.
</EPM-HTML>"
5087;OuterCurve;Bounded curve, defining the outer boundaries of the arbitrary profile.
5092;InnerCurves;Set of bounded curves, defining the inner boundaries of the arbitrary profile.
5097;Profiles;The profiles which are used to define the composite profile.
5098;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.
5103;ParentProfile;The parent profile provides the origin of the transformation.
5104;Operator;Transformation operator applied to the parent profile.
5105;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.
5108;Operator;
5113;ProfileDefinition;Profile definition which is qualified by these properties.
5114;Name;The name given to the set of properties
5115;Description;Description of the set of properties
5116;HasProperties;Properties of the profile
5119;OverallWidth;Total extent of the width, defined parallel to the x axis of the position coordinate system.
5120;OverallDepth;Total extent of the depth, defined parallel to the y axis of the position coordinate system.
5121;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.
5122;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.
5123;FilletRadius;The fillet between the web and the flange.
5128;TopFlangeWidth;Extent of the top flange, defined parallel to the x axis of the position coordinate system.
5129;TopFlangeThickness;Flange thickness of the top flange of the I-shape.
5130;TopFlangeFilletRadius;The fillet between the web and the top flange of the I-shape.
5132;Depth;Leg length, see illustration above (= h). Same as the overall depth.
5133;Width;Leg length, see illustration above (= b). Same as the overall width.
5134;Thickness;Constant wall thickness of profile, see illustration above (= ts).
5135;FilletRadius;Fillet radius according the above illustration (= r1).
5136;EdgeRadius;Edge radius according the above illustration (= r2).
5137;LegSlope;Slope of the inner face of each leg of the profile.
5140;Depth;Web lengths, see illustration above (= h).
5141;FlangeWidth;Flange lengths, see illustration above (= b).
5142;WebThickness;Constant wall thickness of web (= ts).
5143;FlangeThickness;Constant wall thickness of flange (= tg).
5144;FilletRadius;Fillet radius according the above illustration (= r1).
5145;EdgeRadius;Edge radius according the above illustration (= r2).
5146;FlangeSlope;Slope of flange of the profile.
5150;Depth;Profile depth, see illustration above (= h).
5151;Width;Profile width, see illustration above (= b).
5152;WallThickness;Constant wall thickness of profile (= ts).
5153;Girth;Lengths of girth, see illustration above (= c).
5154;InternalFilletRadius;Internal fillet radius according the above illustration (= r1).
5159;Depth;Web length, see illustration above (= h).
5160;FlangeWidth;Flange length, see illustration above (= b).
5161;WebThickness;Constant wall thickness of web, see illustration above (= ts).
5162;FlangeThickness;Constant wall thickness of flange, see illustration above (= tg).
5163;FilletRadius;Fillet radius according the above illustration (= r1).
5164;EdgeRadius;Edge radius according the above illustration (= r2).
5167;Depth;Web lengths, see illustration above (= h).
5168;FlangeWidth;Flange lengths, see illustration above (= b).
5169;WebThickness;Constant wall thickness of web (= ts).
5170;FlangeThickness;Constant wall thickness of flange (= tg).
5171;FilletRadius;Fillet radius according the above illustration (= r1).
5172;FlangeEdgeRadius;Edge radius according the above illustration (= r2).
5173;WebEdgeRadius;Edge radius according the above illustration (= r3).
5174;WebSlope;Slope of flange of the profile.
5175;FlangeSlope;Slope of web of the profile.
5180;Radius;The radius of the circle.
5182;WallThickness;Thickness of the material, it is the difference between the outer and inner radius.
5185;SemiAxis1;The first radius of the ellipse. It is measured along the direction of Position.P[1].
5186;SemiAxis2;The second radius of the ellipse. It is measured along the direction of Position.P[2].
5190;XDim;The extent of the rectangle in the direction of the x-axis.
5191;YDim;The extent of the rectangle in the direction of the y-axis.
5193;WallThickness;Thickness of the material.
5194;InnerFilletRadius;Inner corner radius.
5195;OuterFilletRadius;Outer corner radius.
5200;RoundingRadius;Radius of the circular arcs by which all four corners of the rectangle are equally rounded.
5203;BottomXDim;The extent of the bottom line measured along the implicit x-axis.
5204;TopXDim;The extent of the top line measured along the implicit x-axis.
5205;YDim;The extent of the distance between the parallel bottom and top lines measured along the implicit y-axis.
5206;TopXOffset;Offset from the beginning of the top line to the bottom line, measured along the implicit x-axis.
5208;TotalCrossSectionArea;The total effective cross-section area of the reinforcement of a specific steel grade.
5209;SteelGrade;The nominal steel grade defined according to local standards.
5210;BarSurface;Indicator for whether the bar surface is plain or textured.
5211;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).
5212;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.
5213;BarCount;The number of bars with identical nominal diameter and steel grade included in the specific reinforcement configuration.
5218;SectionType;An indicator whether a specific piece of a cross section is uniform or tapered in longitudinal direction.
5219;StartProfile;The cross section profile at the start point of the longitudinal section.
5220;EndProfile;The cross section profile at the end point of the longitudinal section.
5225;LongitudinalStartPosition;The start position in longitudinal direction for the section reinforcement properties.
5226;LongitudinalEndPosition;The end position in longitudinal direction for the section reinforcement properties.
5227;TransversePosition;The position for the section reinforcement properties in transverse direction.
5228;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.
5229;SectionDefinition;Definition of the cross section profile and longitudinal section type.
5230;CrossSectionReinforcementDefinitions;The set of reinforcment properties attached to a section reinforcement properties definition.
5244;ApplicationDeveloper;"Name of the application developer, being requested to be member of the IAI.
"
5245;Version;The version number of this software as specified by the developer of the application.
5246;ApplicationFullName;The full name of the application as specified by the application developer.
5247;ApplicationIdentifier;Short identifying name for the application.
5254;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."
5255;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 application to another and therefore distinguishes between the Owning Application and Creating Application."
5256;State;Enumeration that defines the current access state of the object.
5257;ChangeAction;Enumeration that defines the actions associated with changes made to the object.
5258;LastModifiedDate;Date and Time expressed in UTC (Universal Time Coordinated, formerly Greenwich Mean Time or GMT) at which the last modification was made by LastModifyingUser and LastModifyingApplication.
5259;LastModifyingUser;User who carried out the last modification using LastModifyingApplication.
5260;LastModifyingApplication;Application used to make the last modification.
5261;CreationDate;The date and time expressed in UTC (Universal Time Coordinated, formerly Greenwich Mean Time or GMT) when first created by the original OwningApplication. Once defined this value remains unchanged through the lifetime of the entity.
5276;Name;A unique name which is intended to describe the usage of the Table.
5277;Rows;Reference to information content of rows.
5278;Columns;The column information associated with this table.
5279;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.
5280;NumberOfHeadings;The number of headings in a table. This is restricted by WR3 to max. one.
5281;NumberOfDataRows;The number of rows in a table that contains data, i.e. total number of rows minus number of heading rows in table.
5285;RowCells;The data value of the table cell..
5286;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.
5287;OfTable;Reference to the IfcTable, in which the IfcTableRow is defined (or contained).
5289;Name;The table column display name.
5290;Description;Descriptive text for the table column.
5291;Identifier;Table column identifier.
5292;Unit;The unit of measure to be used for this column's data.
5297;Operator;"<EPM-HTML>
The Boolean operator used in the operation to create the result.
</EPM-HTML>"
5298;FirstOperand;"<EPM-HTML>
The first operand to be operated upon by the Boolean operation.
</EPM-HTML>"
5299;SecondOperand;"<EPM-HTML>
The second operand specified for the operation.
</EPM-HTML>"
5300;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.
5307;BaseSurface;Surface defining side of half space.
5308;AgreementFlag;The agreement flag is TRUE if the normal to the BaseSurface points away from the material of the IfcHalfSpaceSolid. Otherwise it is FALSE.
5309;Dim;The space dimensionality of this class, it is always 3
5311;Enclosure;"<EPM-HTML>
The box which bounds the resulting solid of the Boolean operation involving the half space solid for computational purposes only.
</EPM-HTML>
"
5314;Corner;Location of the bottom left corner (having the minimum values).
5315;XDim;Length attribute (measured along the edge parallel to the X Axis)
5316;YDim;Width attribute (measured along the edge parallel to the Y Axis)
5317;ZDim;Height attribute (measured along the edge parallel to the Z Axis).
5318;Dim;The space dimensionality of this class, it is always 3.
5320;Position;"<EPM-HTML>
<P>Definition of the position coordinate system for the bounding polyline <STRIKE>and the base surface</STRIKE>.</P>
</EPM-HTML>"
5321;PolygonalBoundary;"<EPM-HTML>
Two-dimensional <strike>polyline</strike> bounded curve, defined in the xy plane of the position coordinate system.
<blockquote><small><font color=""#ff0000"">
IFC2x Edition 3 CHANGE&nbsp; The attribute type has been changed from <i>IfcPolyline</i> to its supertype <i>IfcBoundedCurve</i> with upward compatibility for file based exchange.
</font></small></blockquote>
</EPM-HTML>"
5329;Dim;The space dimensionality of this class, it is always 3.
5333;Outer;A closed shell defining the exterior boundary of the solid. The shell normal shall point away from the interior of the solid.
5337;Voids;Set of closed shells defining voids within the solid.
5342;Voids;
5349;SweptArea;"<EPM-HTML>
The surface defining the area to be swept. It is given as a profile definition within the xy plane of the position coordinate system.
</EPM-HTML>"
5350;Position;"<EPM-HTML>
Position coordinate system for the swept area, provided by a profile definition within the XY plane of the <i>Position</i>.
</EPM-HTML>"
5354;ExtrudedDirection;"<EPM-HTML>
The direction in which the surface, provided by <i>SweptArea</i> is to be swept.
</EPM-HTML>"
5355;Depth;"<EPM-HTML>
The distance the surface is to be swept along the <i>ExtrudedDirection</i>
</EPM-HTML>."
5358;EndSweptArea;"<EPM-HTML>
The surface defining the end of the swept area. It is given as a profile definition. The position coordinate system of the <i>EndSwptArea</i> is generated by translating the <i>SELF\IfcSweptAreaSolid.Position</i> along the <i>SELF\IfcExtrudedAreaSolid.ExtrudedDirection</i> by the distance of <i>SELF\IfcExtrudedAreaSolid.Depth</i>.
</EPM-HTML>"
5362;Axis;"<EPM-HTML>
Axis about which revolution will take place.
</EPM-HTML>"
5363;Angle;"<EPM-HTML>
The angle through which the sweep will be made. This angle is measured from the plane of the swept area provided by the XY plane of the position coordinate system.
</EPM-HTML>"
5364;AxisLine;"<EPM-HTML>
The line of the axis of revolution.
</EPM-HTML>"
5368;EndSweptArea;
5371;Directrix;"<EPM-HTML>
The curve used to define the sweeping operation. The solid is generated by sweeping the <i>SELF\IfcSweptAreaSolid.SweptArea</i> along the <i>Directrix</i>.
</EPM-HTML>"
5372;StartParam;"<EPM-HTML>
The parameter value on the <i>Directrix</i> at which the sweeping operation commences. <font color=""#0000ff"">If no value is provided the start of the sweeping operation is at the start of the <i>Directrix</i>.</font>.
<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The attribute has been changed to OPTIONAL with upward compatibility for file-based exchange.</font></small>
</blockquote>
</EPM-HTML>"
5373;EndParam;"<EPM-HTML>
The parameter value on the <i>Directrix</i> at which the sweeping operation ends. <font color=""#0000ff"">If no value is provided the end of the sweeping operation is at the end of the <i>Directrix</i>.</font>.
<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The attribute has been changed to OPTIONAL with upward compatibility for file-based exchange.</font></small>
</blockquote>
</EPM-HTML>"
5374;ReferenceSurface;"<EPM-HTML>
The surface containing the <i>Directrix</i>.
</EPM-HTML>"
5376;Directrix;"<EPM-HTML>
The curve used to define the sweeping operation. The solid is generated by sweeping the <i>SELF\IfcSweptAreaSolid.SweptArea</i> along the <i>Directrix</i>.
</EPM-HTML>"
5377;StartParam;"<EPM-HTML>
The parameter value on the <i>Directrix</i> at which the sweeping operation commences. <span style=""color:blue"">If no value is provided the start of the sweeping operation is at the start of the <i>Directrix</i>.</span>
</EPM-HTML>"
5378;EndParam;"<EPM-HTML>
The parameter value on the <i>Directrix</i> at which the sweeping operation ends. < style=""color:blue"">If no value is provided the end of the sweeping operation is at the end of the <i>Directrix</i>.</span>
</EPM-HTML>"
5379;FixedReference;"<EPM-HTML>
The direction providing the fixed axis1 (x-axis) direction for orienting the swept area during the sweeping operation along the <i>Directrix</i>.
</EPM-HTML>"
5381;TreeRootExpression;"<EPM-HTML>
Boolean expression of primitives and regularized operators describing the solid. The root of the tree of Boolean expressions is given explicitly as an <i>IfcBooleanResult</i> entitiy or as a primitive (subtypes of <i>IfcCsgPrimitive3D</i>).
</EPM-HMTL>"
5391;Position;"<EPM-HTML>
The placement coordinate system to which the parameters of each individual CSG primitive apply.
</EPM-HTML>"
5392;Dim;"<EPM-HTML>
The space dimensionality of this geometric representation item, it is always 3.
</EPM-HTML>"
5394;XLength;"<EPM-HTML>
The size of the block along the placement X axis. It is provided by the inherited axis placement through <i>SELF\IfcCsgPrimitive3D.Position.P[1]</i>.
</EPM-HTML>"
5395;YLength;"<EPM-HTML>
The size of the block along the placement Y axis. It is provided by the inherited axis placement through <i>SELF\IfcCsgPrimitive3D.Position.P[2]</i>.
</EPM-HTML>"
5396;ZLength;"<EPM-HTML>
The size of the block along the placement Z axis. It is provided by the inherited axis placement through <i>SELF\IfcCsgPrimitive3D.Position.P[3]</i>.
</EPM-HTML>"
5398;XLength;"<EPM-HTML>
The length of the base measured along the placement X axis. It is provided by the inherited axis placement through <i>SELF\IfcCsgPrimitive3D.Position.P[1]</i>.
</EPM-HTML>"
5399;YLength;"<EPM-HTML>
The length of the base measured along the placement Y axis. It is provided by the inherited axis placement through <i>SELF\IfcCsgPrimitive3D.Position.P[2]</i>.
</EPM-HTML>"
5400;Height;"<EPM-HTML>
The height of the apex above the plane of the base, measured in the direction of the placement Z axis, the <i>SELF\IfcCsgPrimitive3D.Position.P[2]</i>.
</EPM-HTML>"
5402;Height;"<EPM-HTML>
The distance between the planar circular faces of the cylinder.
</EPM-HTML>"
5403;Radius;"<EPM-HTML>
The radius of the cylinder.
</EPM-HTML>"
5405;Height;"<EPM-HTML>
The distance between the base of the cone and the apex.
</EPM-HTML>"
5406;BottomRadius;"<EPM-HTML>
The radius of the cone at the base.
</EPM-HTML>"
5408;Radius;"<EPM-HTML>
The radius of the sphere.
</EPM-HTML>"
5411;Directrix;"<EPM-HTML>
The curve used to define the sweeping operation. The solid is generated by sweeping a circular disk along the <i>Directrix</i>.
</EPM-HTML>"
5412;Radius;"<EPM-HTML>
The <i>Radius</i> of the circular disk to be swept along the <i>directrix</i>. Denotes the outer radius, if an <i>InnerRadius</i> is applied.
</EPM-HTML>"
5413;InnerRadius;"<EPM-HTML>
This attribute is optional, if present it defines the radius of a circular hole in the centre of the disk.
</EPM-HTML>"
5414;StartParam;"<EPM-HTML>
The parameter value on the <i>Directrix</i> at which the sweeping operation commences. <font color=""#0000ff"">If no value is provided the start of the sweeping operation is at the start of the <i>Directrix</i>.</font>.
<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The attribute has been changed to OPTIONAL with upward compatibility for file-based exchange.</font></small>
</blockquote>
</EPM-HTML>"
5415;EndParam;"<EPM-HTML>
The parameter value on the <i>Directrix</i> at which the sweeping operation ends. <font color=""#0000ff"">If no value is provided the end of the sweeping operation is at the end of the <i>Directrix</i>.</font>.
<blockquote>
<small><font color=""#ff0000"">IFC2x4 CHANGE&nbsp; The attribute has been changed to OPTIONAL with upward compatibility for file-based exchange.</font></small>
</blockquote>
</EPM-HTML>"
5420;FilletRadius;"<EPM-HTML>
The fillet that is equally applied to all transitions between the segments of the <i>IfcPolyline</i>, providing the geometric representation for <i>the Directrix</i>. If omited, no fillet is applied to the segments. 
</EPM-HTML>"
5424;SpineCurve;A single composite curve, that defines the spine curve. Each of the composite curve segments correspond to the part between two cross-sections.
5425;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.
5426;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.
5427;Dim;The dimensionality of the spine curve is always 3.
5433;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."
5434;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.
5443;FbsmFaces;The set of connected face sets comprising the face based surface model.
5444;Dim;The space dimensionality of this class, it is always 3.
5446;SbsmBoundary;
5447;Dim;The space dimensionality of this class, it is always 3.
5469;RefDirection;"<EPM-HTML>
The direction used to determine the direction of the local X axis. If a value is omited that it defaults to [1.0, 0.0.].
</HTML>"
5470;P;"<EPM-HTML>
<i>P[1]</i>: The normalized direction of the placement X Axis. This is [1.0,0.0] if <i>RefDirection</i> is omitted.<br> 
<i>P[2]</i>: The normalized direction of the placement Y Axis. This is a derived attribute and is orthogonal to P[1]. If <i>RefDirection</i> is omitted, it defaults to [0.0,1.0]
</EPM-HTML>"
5477;Location;The geometric position of a reference point, such as the center of a circle, of the item to be located.
5478;Dim;The space dimensionality of this class, derived from the dimensionality of the location.
5501;LayerAssignment;"<EPM-HTML>Assignment of the representation item to a single or multiple layer(s). The <i>LayerAssignments</i> can override a <i>LayerAssignments</i> of the <i>IfcRepresentation</i> it is used  within the list of <i>Items</i>.
<blockquote>
  <small><font color=""#ff0000"">
    IFC2x3 CHANGE&nbsp; The inverse attribute <i>LayerAssignments</i> has been added.
  </font></small><br>
  <small><font color=""#ff0000"">
    IFC2x4 CHANGE&nbsp; The inverse attribute <i>LayerAssignment</i> has
been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
  </font></small>
</blockquote>
</EPM-HTML>"
5502;StyledByItem;"<EPM-HTML>
Reference to the <i>IfcStyledItem</i> that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.
  <blockquote>
<small><font color=""#ff0000"">IFC2x Edition 3 CHANGE&nbsp; The inverse attribute <i>StyledByItem</i> has been added.</font></small>
</blockquote>
</EPM-HTML>"
5504;MappingSource;A representation map that is the source of the mapped item. It can be seen as a block (or cell or marco) definition.
5505;MappingTarget;A representation item that is the target onto which the mapping source is mapped. It is constraint to be a Cartesian transformation operator.
5507;MappingOrigin;"An axis2 placement that defines the position about which the mapped
representation is mapped."
5508;MappedRepresentation;A representation that is mapped to at least one mapped item.
5509;MapUsage;
5514;Axis1;The direction used to determine U[1], the derived X axis direction.
5515;Axis2;The direction used to determine U[2], the derived Y axis direction.
5516;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.
5517;Scale;The scaling value specified for the transformation.
5518;Scl;The derived scale S of the transformation, equal to scale if that exists, or 1.0 otherwise.
5519;Dim;"The space dimensionality of this class, determined by the space dimensionality of the local origin.
"
5523;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.
5528;Scale2;The scaling value specified for the transformation along the axis 2. This is normally the y scale factor.
5529;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.
5532;DirectionRatios;"The components in the direction of X axis (DirectionRatios[1]), of Y axis (DirectionRatios[2]), and of Z axis (DirectionRatios[3]) 
"
5533;Dim;The space dimensionality of this class, defined by the number of real in the list of DirectionRatios.
5536;Axis3;The exact direction of U[3], the derived Z axis direction.
5537;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.
5543;Scale2;The scaling value specified for the transformation along the axis 2. This is normally the y scale factor.
5544;Scale3;The scaling value specified for the transformation along the axis 3. This is normally the z scale factor.
5545;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.
5546;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.
5550;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.
"
5551;Dim;"The space dimensionality of this class, determined by the number of coordinates in the List of Coordinates.
"
5558;BasisCurve;The curve to which point parameter relates.
5559;PointParameter;The parameter value of the point location.
5560;Dim;The space dimensionality of this class, determined by the space dimensionality of the basis curve.
5568;Dim;The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.
5576;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."
5577;SelfIntersect;"Indication of whether the curve intersects itself or not; this is for information only.
"
5578;NSegments;The number of component curves.
5579;ClosedCurve;"Indication whether the curve is closed or not; this is derived from the transition code of the last segment."
5584;BasisSurface;"<EPM-HTML>
The surface on which the composite curve is defined.
</EPM-HTML>"
5594;Dim;"<EPM-HTML>
The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item.
<blockquote>
  <small>
    <font color=""#ff0000"">IFC2x4 CHANGE  Derived attribute promoted from subtypes.
    </form>
  </small>
</blockquote>
</EPM-HTML>"
5598;Position;"The position and orientation of the surface. This attribute is used in the definition of the parameterization of the surface.
"
5601;Radius;"<EPM-HTML>
The radius of the cylindrical surface.
</EPM-HTML>"
5603;Axis;The exact direction of the local Z Axis.
5604;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.
5605;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]).
5614;SweptCurve;The curve to be swept in defining the surface. The curve is defined as a profile within the position coordinate system.
5615;Position;Position coordinate system for the placement of the profile within the xy plane of the axis placement.
5619;AxisPosition;A point on the axis of revolution and the direction of the axis of revolution.
5620;AxisLine;The line coinciding with the axis of revolution.
5622;Axis;The direction of the local Z axis.
5623;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.]
5627;Pnt;The location of the line.
5628;Dir;The direction of the line, the magnitude and units of Dir affect the parameterization of the line.
5631;Orientation;The direction of the vector.
5632;Magnitude;The magnitude of the vector. All vectors of Magnitude 0.0 are regarded as equal in value regardless of the orientation attribute.
5633;Dim;The space dimensionality of this class, it is derived from Orientation
5636;ExtrudedDirection;The direction of the extrusion.
5637;Depth;The depth of the extrusion, it determines the parameterization.
5638;ExtrusionAxis;The extrusion axis defined as vector.
5646;BasisSurface;The surface to be bound.
5647;OuterBoundary;The outer boundary of the surface.
5648;InnerBoundaries;An optional set of inner boundaries. They shall not intersect each other or the outer boundary.
5650;BasisSurface;Surface being trimmed.
5651;U1;First u parametric value.
5652;V1;First v parametric value.
5653;U2;Second u parametric value.
5685;KnotSpec;"<EPM-HTML>
The description of the knot type.
</EPM-HTML>"
5686;KnotVUpper;"<EPM-HTML>
The number of distinct knots in the <i>v</i> parameter direction.
</EPM-HTML>"
5687;KnotUUpper;"<EPM-HTML>
The number of distinct knots in the <i>u</i> parameter direction.
</EPM-HTML>"
5693;WeightsData;"<EPM-HTML>
The weights associated with the control points in the rational case.
</EPM-HTML>"
5695;Weights;"<EPM-HTML>
Array (two-dimensional) of weight values constructed from the <i>WeightsData</i>.
</EPM-HTML>"
5718;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.
5719;SameSense;"<EPM-HTML>
An indicator of whether or not the sense of the segment agrees with, or opposes, that of the parent curve. If <i>SameSense</i> is false, the point with highest parameter value is taken as the first point of the segment.
<blockquote>
  <small>NOTE&nbsp; If the datatype of <i>ParentCurve</i> is <i>IfcTrimmedCurve</i>, the value of <i>SameSense</i> overrides the value of <i>IfcTrimmedCurve.SenseAgreement</i></small>
</blockquote>
</EPM-HTML>"
5720;ParentCurve;The bounded curve which defines the geometry of the segment.
5721;Dim;The space dimensionality of this class, defined by the dimensionality of the first ParentCurve.
5722;UsingCurves;The set of composite curves which use this composite curve segment as a segment. This set shall not be empty.
5725;ParamLength;
5733;Points;The points defining the polyline.
5736;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.
5737;Trim1;The first trimming point which may be specified as a Cartesian point, as a real parameter or both.
5738;Trim2;The second trimming point which may be specified as a Cartesian point, as a real parameter or both.
5739;SenseAgreement;Flag to indicate whether the direction of the trimmed curve agrees with or is opposed to the direction of the basis curve.
5740;MasterRepresentation;Where both parameter and point are present at either end of the curve this indicates the preferred form.
5753;Degree;The algebraic degree of the basis functions.
5754;ControlPointsList;The list of control points for the curve.
5755;CurveForm;"Used to identify particular types of curve; it is for information only."
5756;ClosedCurve;"Indication of whether the curve is closed; it is for information only."
5757;SelfIntersect;"Indication whether the curve self-intersects or not; it is for information only."
5758;ControlPoints;The array of control points used to define the geometry of the curve. This is derived from the list of control points.
5759;UpperIndexOnControlPoints;"The upper index on the array of control points; the lower index is 0.
This value is derived from the control points list."
5763;KnotMultiplicities;"<EPM-HTML>
The multiplicities of the knots. This list defines the number of times each knot in the knots list is to be repeated in constructing the knot array.
</EPM-HTML>"
5764;Knots;"<EPM-HTML>
The list of distinct knots used to define the B-spline basis functions.
</EPM-HTML>"
5765;KnotSpec;"<EPM-HTML>
The description of the knot type. This is for information only.
</EPM-HTML>"
5766;UpperIndexOnKnots;"<EPM-HTML>
The upper index on the knot arrays; the lower index is 1.
</EPM-HTML>"
5770;WeightsData;"<EPM-HTML>
The supplied values of the weights.
</EPM-HTML>"
5771;Weights;"<EPM-HTML>
The array of weights associated with the control points. This is derived from the weights data.
</EPM-HTML>"
5784;Position;"The location and orientation of the conic. Further details of the interpretation of this attribute are given for the individual subtypes."" 
"
5786;Radius;The radius of the circle, which shall be greater than zero.
5788;SemiAxis1;The first radius of the ellipse which shall be positive. Placement.Axes[1] gives the direction of the SemiAxis1.
5789;SemiAxis2;The second radius of the ellipse which shall be positive.
5791;BasisCurve;The curve that is being offset.
5792;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).)
5793;SelfIntersect;"An indication of whether the offset curve self-intersects; this is for information only."
5796;BasisCurve;The curve that is being offset.
5797;Distance;The distance of the offset curve from the basis curve. The distance may be positive, negative or zero.
5798;SelfIntersect;An indication of whether the offset curve self-intersects, this is for information only.
5799;RefDirection;The direction used to define the direction of the offset curve 3d from the basis curve.
5802;BasisSurface;
5803;ReferenceCurve;
5806;BasisSurface;The surface to which the parameter values relate.
5807;PointParameterU;The first parameter value of the point location.
5808;PointParameterV;The second parameter value of the point location.
5809;Dim;The space dimensionality of this class, determined by the space dimensionality of the basis surface.
