8.16.3.9 IfcPropertyEnumeration

8.16.3.9.1 Semantic 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 8.16.3.9.A 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 8.16.3.9.A — Property enumeration with values, measure types and units

8.16.3.9.2 Entity inheritance

- IfcPropertyAbstraction

8.16.3.9.3 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.
Click to show 1 hidden inherited attributes Click to hide 1 inherited attributes
IfcPropertyEnumeration (3)
1	Name	IfcLabel	Name of this enumeration.
2	EnumerationValues	LIST [1:?] OF UNIQUE IfcValue	List of values that form the enumeration.
3	Unit	OPTIONAL 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.

Table 8.16.3.9.B

8.16.3.9.4 Formal propositions

Name	Description
WR01	All values within the list of EnumerationValues shall be of the same measure type.
`SIZEOF(QUERY(temp <* SELF.EnumerationValues \| NOT(TYPEOF(SELF.EnumerationValues[1]) = TYPEOF(temp)) )) = 0`
UR1	The attribute Name should be unique

Table 8.16.3.9.C

8.16.3.9.5 Formal representation

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;