Propriété à valeurs énumérées
Merkmal - Aufzählung

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 690 for an example of a unitless property enumeration:


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

Table 690 — 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

XSD Specification:

 <xs:element name="IfcPropertyEnumeration" type="ifc:IfcPropertyEnumeration" substitutionGroup="ifc:IfcPropertyAbstraction" nillable="true"/>
 <xs:complexType name="IfcPropertyEnumeration">
   <xs:extension base="ifc:IfcPropertyAbstraction">
     <xs:element name="EnumerationValues">
       <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:element name="Unit" nillable="true" minOccurs="0">
       <xs:group ref="ifc:IfcUnit"/>
    <xs:attribute name="Name" type="ifc:IfcLabel" use="optional"/>

EXPRESS Specification:

ENTITY IfcPropertyEnumeration
SUBTYPE OF IfcPropertyAbstraction;
Name : IfcLabel;
EnumerationValues : LIST [1:?] OF UNIQUE IfcValue;
Unit : OPTIONAL IfcUnit;
UR1 : Name;
WR01 : SIZEOF(QUERY(temp <* SELF.EnumerationValues | NOT(TYPEOF(SELF.EnumerationValues[1]) = TYPEOF(temp)) )) = 0;

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

Name : Name of this enumeration.
EnumerationValues : List of values that form the enumeration.
Unit : Unit for the enumerator values, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject.

Formal Propositions:

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

Inheritance Graph:

ENTITY IfcPropertyEnumeration
ENTITY IfcPropertyAbstraction
HasExternalReferences : SET OF IfcExternalReferenceRelationship FOR RelatedResourceObjects;
ENTITY IfcPropertyEnumeration
Name : IfcLabel;
EnumerationValues : LIST [1:?] OF UNIQUE IfcValue;
Unit : OPTIONAL IfcUnit;

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