IfcPropertyEnumeration

Semantic definitions at the entity

Entity definition

IfcPropertyEnumeration is a collection of simple or measure values that define a prescribed set of alternatives from which 'enumeration values' are selected. This enables inclusion of enumeration values in property sets. IfcPropertyEnumeration provides a name for the enumeration as well as a list of unique (numeric or descriptive) values (that may have a measure type assigned). The entity defines the list of potential enumerators to be exchanged together (or separately) with properties of type IfcPropertyEnumeratedValue that selects their actual property values from this enumeration.

The unit is handled by the Unit attribute, see Table 771 for an example of a unitless property enumeration:

If the Unit attribute is not given, than the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext).
If the Unit attribute is given, the unit assigned by the unit attribute overrides the globally assigned unit.

Name	EnumerationValues	Type (through IfcValue)	Unit
PEnum_DamperBladeAction	Parallel	IfcLabel	-
	Opposed	IfcLabel
	Other	IfcLabel
	Unset	IfcLabel

Table 771 — Property enumeration with values, measure types and units

HISTORY New entity in IFC2.0, capabilities enhanced in IFC2x.

IFC2x CHANGE Entity has been renamed from IfcEnumeration

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
1	Name	IfcLabel		Name of this enumeration.	X
2	EnumerationValues	IfcValue	L[1:?]	List of values that form the enumeration.	X
3	Unit	IfcUnit	?	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.	X

Formal Propositions

Rule	Description
WR01	All values within the list of EnumerationValues shall be of the same measure type.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcPropertyAbstraction
	HasExternalReferences	IfcExternalReferenceRelationship @RelatedResourceObjects	S[0:?]	Reference to an external reference, e.g. library, classification, or document information, that is associated to the property definition. IFC4 CHANGE New inverse attribute.	X
IfcPropertyEnumeration
1	Name	IfcLabel		Name of this enumeration.	X
2	EnumerationValues	IfcValue	L[1:?]	List of values that form the enumeration.	X
3	Unit	IfcUnit	?	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.	X

Formal representations

XML Specification

 <xs:element name="IfcPropertyEnumeration" type="ifc:IfcPropertyEnumeration" substitutionGroup="ifc:IfcPropertyAbstraction" nillable="true"/>

 <xs:complexType name="IfcPropertyEnumeration">

  <xs:complexContent>

   <xs:extension base="ifc:IfcPropertyAbstraction">

    <xs:sequence>

     <xs:element name="EnumerationValues">

      <xs:complexType>

       <xs:group ref="ifc:IfcValue" maxOccurs="unbounded"/>

       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcValue"/>

       <xs:attribute ref="ifc:cType" fixed="list-unique"/>

       <xs:attribute ref="ifc:arraySize" use="optional"/>

      </xs:complexType>

     </xs:element>

     <xs:element name="Unit" nillable="true" minOccurs="0">

      <xs:complexType>

       <xs:group ref="ifc:IfcUnit"/>

      </xs:complexType>

     </xs:element>

    </xs:sequence>

    <xs:attribute name="Name" type="ifc:IfcLabel" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcPropertyEnumeration

 SUBTYPE OF (IfcPropertyAbstraction);

  Name : IfcLabel;

  EnumerationValues : LIST [1:?] OF UNIQUE IfcValue;

  Unit : OPTIONAL IfcUnit;

 UNIQUE

  UR1 : Name;
 WHERE

  WR01 : SIZEOF(QUERY(temp <* SELF.EnumerationValues | 

  NOT(TYPEOF(SELF.EnumerationValues[1]) = TYPEOF(temp))

  )) = 0;
END_ENTITY;

 EXPRESS-G diagram

	Merkmal - Aufzählung
	Property Enumeration
	Propriété à valeurs énumérées