8.16.3.8 IfcPropertyEnumeratedValue

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8.16.3.8.1 Semantic 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.

The unit is handled by the Unit attribute, see Table 8.16.3.8.A 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.

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

Table 8.16.3.8.A — Enumerated property with values, measure types and units

The IfcPropertyEnumeratedValue refers to an IfcPropertyEnumeration, see Table 8.16.3.8.B for an example:

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

Table 8.16.3.8.B — 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.

8.16.3.8.2 Entity inheritance

8.16.3.8.3 Attributes

#	Attribute	Type	Description
IfcPropertyAbstraction (1)
	HasExternalReferences	SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects	Reference to an external reference, e.g. library, classification, or document information, that is associated to the property definition. IFC4-CHANGE New inverse attribute.
IfcProperty (8)
1	Name	IfcIdentifier	Name for this property. This label is the significant name string that defines the semantic meaning for the property.
2	Specification	OPTIONAL IfcText	URI reference to a location with semantic definition or informative text to explain the property.
	PartOfPset	SET [0:?] OF IfcPropertySet FOR HasProperties	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.
	PropertyForDependance	SET [0:?] OF IfcPropertyDependencyRelationship FOR DependingProperty	The property on whose value that of another property depends.
	PropertyDependsOn	SET [0:?] OF IfcPropertyDependencyRelationship FOR DependantProperty	The relating property on which the value of the property depends.
	PartOfComplex	SET [0:?] OF IfcComplexProperty FOR HasProperties	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.
	HasConstraints	SET [0:?] OF IfcResourceConstraintRelationship FOR RelatedResourceObjects	User-defined constraints for the property.
	HasApprovals	SET [0:?] OF IfcResourceApprovalRelationship FOR RelatedResourceObjects	User-defined approvals for the property.
Click to show 9 hidden inherited attributes
IfcPropertyEnumeratedValue (2)
3	EnumerationValues	OPTIONAL LIST [1:?] OF IfcValue	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.
4	EnumerationReference	OPTIONAL IfcPropertyEnumeration	Enumeration from which a enumeration value has been selected. The referenced enumeration also establishes the unit of the enumeration value.

Table 8.16.3.8.C

8.16.3.8.4 Formal propositions

Name 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).

 NOT(EXISTS(EnumerationReference)) 
OR  NOT(EXISTS(EnumerationValues)) 
OR  (SIZEOF(QUERY(temp <* EnumerationValues |
    temp IN EnumerationReference.EnumerationValues))
    = SIZEOF(EnumerationValues))

Table 8.16.3.8.D

8.16.3.8.5 Formal representation

 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;

8.16.3.8.6 References

IfcSimpleProperty