IfcPropertyEnumeratedValue

Semantic definitions at the entity

Entity definition

A property with an enumerated value, IfcPropertyEnumeratedValue, defines a property object which has a value assigned that is chosen from an enumeration. It defines a property - value combination for which the property Name, an optional Description, the optional EnumerationValues with measure type and optionally an Unit is given.

NOTE Multiple choices from the property enumeration are supported.

The unit is handled by the Unit attribute, see Table 686 for an example of a enumerated property:

If the Unit attribute is not given, then 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, then the unit assigned by the unit attribute overrides the globally assigned unit.

More precisely: The IfcPropertyEnumeratedValue defines a property, which value is selected from a defined list of enumerators. The enumerators are stored in a dynamic enumeration of values including the type information from IfcValue (see IfcPropertyEnumeration). This enables applications to use an enumeration value as a property within a property set (IfcPropertySet) including the allowed list of values.

NOTE An IfcPropertyEnumeratedValue may be exchanged with no values assigned yet. In this case the EnumerationValues are set to NIL.

Name	Value (EnumerationValue)	Type (through IfcValue)	IfcPropertyEnumeration (Name)
BladeAction	Opposed	IfcLabel	DamperBladeActionEnum
BladeAction	Parallel	IfcLabel	DamperBladeActionEnum

Table 686 — Enumerated property with values, measure types and units

The IfcPropertyEnumeratedValue refers to an IfcPropertyEnumeration, see Table 687 for an example:

Name	EnumerationValues	Type (through IfcValue)	Unit
DamperBladeActionEnum	(Parallel, Opposed, Other, Unset)	IfcString	-

Table 687 — Property enumeration with enumerators

It is not mandatory to use an instance of IfcPropertyEnumeration to hold the applicable values for IfcPropertyEnumeratedValue, however this is the preferred way. A single instance of IfcPropertyEnumeration can be referenced by multiple instances of IfcPropertyEnumeratedValue.

HISTORY New entity in IFC2.0.

IFC2x CHANGE Entity has been renamed from IfcEnumeratedProperty

IFC4 CHANGE Attribute EnumerationValues has been made OPTIONAL with upward compatibility for file based exchange.

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
3	EnumerationValues	IfcValue	? L[1:?]	Enumeration values, which shall be listed in the referenced IfcPropertyEnumeration, if such a reference is provided. IFC4 CHANGE The attribute has been made optional with upward compatibility for file based exchange.	X
4	EnumerationReference	IfcPropertyEnumeration	?	Enumeration from which a enumeration value has been selected. The referenced enumeration also establishes the unit of the enumeration value.	X

Formal Propositions

Rule	Description
WR21	Each value within the list of EnumerationValues shall be a member of the list of EnumerationValues at the referenced IfcPropertyEnumeration (provided that both, the EnumerationValues and EnumerationReference, are asserted).

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
IfcProperty
1	Name	IfcIdentifier		Name for this property. This label is the significant name string that defines the semantic meaning for the property.	X
2	Description	IfcText	?	Informative text to explain the property.	X
	PartOfPset	IfcPropertySet @HasProperties	S[0:?]	Reference to the IfcPropertySet by which the IfcProperty is referenced. IFC4 CHANGE New inverse attribute to navigate from IfcProperty to IfcPropertySet with upward compatibility for file based exchange.	X
	PropertyForDependance	IfcPropertyDependencyRelationship @DependingProperty	S[0:?]	The property on whose value that of another property depends.	X
	PropertyDependsOn	IfcPropertyDependencyRelationship @DependantProperty	S[0:?]	The relating property on which the value of the property depends.	X
	PartOfComplex	IfcComplexProperty @HasProperties	S[0:?]	Reference to the IfcComplexProperty in which the IfcProperty is contained. IFC4 CHANGE The cardinality has changed to 0..n to allow reuse of instances of IfcProperty in several IfcComplexProperty with upward compatibility for file based exchange.	X
	HasConstraints	IfcResourceConstraintRelationship @RelatedResourceObjects	? S[0:?]	User-defined constraints for the property.	X
	HasApprovals	IfcResourceApprovalRelationship @RelatedResourceObjects	? S[0:?]	User-defined approvals for the property.	X
IfcSimpleProperty
IfcPropertyEnumeratedValue
3	EnumerationValues	IfcValue	? L[1:?]	Enumeration values, which shall be listed in the referenced IfcPropertyEnumeration, if such a reference is provided. IFC4 CHANGE The attribute has been made optional with upward compatibility for file based exchange.	X
4	EnumerationReference	IfcPropertyEnumeration	?	Enumeration from which a enumeration value has been selected. The referenced enumeration also establishes the unit of the enumeration value.	X

Formal representations

XML Specification

 <xs:element name="IfcPropertyEnumeratedValue" type="ifc:IfcPropertyEnumeratedValue" substitutionGroup="ifc:IfcSimpleProperty" nillable="true"/>

 <xs:complexType name="IfcPropertyEnumeratedValue">

  <xs:complexContent>

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

    <xs:sequence>

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

      <xs:complexType>

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

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

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

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

      </xs:complexType>

     </xs:element>

     <xs:element name="EnumerationReference" type="ifc:IfcPropertyEnumeration" nillable="true" minOccurs="0"/>

    </xs:sequence>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcPropertyEnumeratedValue

 SUBTYPE OF (IfcSimpleProperty);

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

  EnumerationReference : OPTIONAL IfcPropertyEnumeration;

 WHERE

  WR21 : NOT(EXISTS(EnumerationReference)) 

OR  NOT(EXISTS(EnumerationValues)) 

OR  (SIZEOF(QUERY(temp <* EnumerationValues |

    temp IN EnumerationReference.EnumerationValues))

    = SIZEOF(EnumerationValues));
END_ENTITY;

 EXPRESS-G diagram

Item	Change	Description
IFC2x3 to IFC4
IfcPropertyEnumeratedValue
EnumerationValues	MODIFIED	Instantiation changed to OPTIONAL.
IFC4 Addendum 1
IfcPropertyEnumeratedValue
HasConstraints	ADDED
HasApprovals	ADDED

	Merkmal mit Aufzählungswert
	Property Enumerated Value
	Propriété à valeur issue d'un énumération