5.1.3.14 IfcPropertySet

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5.1.3.14.1 Semantic definition

The IfcPropertySet is a container that holds properties within a property tree. These properties are interpreted according to their name attribute. Each individual property has a significant name string. Some property sets are included in the specification of this standard and have a predefined set of properties indicated by assigning a significant name. These property sets are listed under "property sets" within this specification. Property sets applicable to certain objects are listed in the object specification. The naming convention "Pset_Xxx" applies to all those property sets that are defined as part of this specification and it shall be used as the value of the Name attribute.

In addition any user defined property set can be captured. Property sets that are not declared as part of the IFC specification shall have a Name value not including the "Pset_" prefix.

IfcPropertySet can be assigned to object occurrences and object types. An IfcPropertySet assigned to an object type is shared among all occurrences of the same object type.

An IfcPropertySetTemplate may define the underlying structure, i.e. the required name, the applicable object or object types to which the property set can be attached, and the individual properties that can be included. Property sets are related to other objects by using the relationship object that refers to the corresponding object:

Occurrence Object: IfcRelDefinesByProperties using the inverse attribute DefinesOccurrence.
Type Object: using a direct link by inverse attribute DefinesType.
Underlying template: IfcRelDefinesByTemplate using the inverse attribute IsDefinedBy.
External reference: subtypes of IfcRelAssociates are used to provide a link to a classification system, or external library providing further reference to the property set. Accessible by inverse attribute HasAssociations.

5.1.3.14.2 Entity inheritance

5.1.3.14.3 Attributes

#	Attribute	Type	Description
IfcRoot (4)
1	GlobalId	IfcGloballyUniqueId	Assignment of a globally unique identifier within the entire software world.
2	OwnerHistory	OPTIONAL IfcOwnerHistory	Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE Only the last modification is stored - either as addition, deletion or modification. IFC4-CHANGE The attribute has been changed to be OPTIONAL.
3	Name	OPTIONAL IfcLabel	Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.
4	Description	OPTIONAL IfcText	Optional description, provided for exchanging informative comments.
IfcPropertyDefinition (2)
	HasContext	SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions	Reference to the relationship IfcRelDeclares and thus to the IfcProject or IfcProjectLibrary.
	HasAssociations	SET [0:?] OF IfcRelAssociates FOR RelatedObjects	Reference to the relationship IfcRelAssociates and thus to those externally defined concepts, like classifications, documents, or library information, which are associated to the property definition.
IfcPropertySetDefinition (3)
	DefinesType	SET [0:?] OF IfcTypeObject FOR HasPropertySets	The type object to which the property set is assigned. The property set acts as a shared property set to all occurrences of the type object. NOTE The relationship between the IfcPropertySetDefinition and the IfcTypeObject is a direct relationship, not utilizing IfcRelDefinesByProperties, for maintaining compatibility with earlier releases of this standard. IFC4-CHANGE The cardinality has been changed from 0:1 to 0:? with upward compatibility for file based exchange.
	IsDefinedBy	SET [0:?] OF IfcRelDefinesByTemplate FOR RelatedPropertySets	Relation to the property set template, via the objectified relationship IfcRelDefinesByTemplate, that, if given, provides the definition template for the property set or quantity set and its properties. IFC4-CHANGE New inverse relationship, change made with upward compatibility for file based exchange.
	DefinesOccurrence	SET [0:?] OF IfcRelDefinesByProperties FOR RelatingPropertyDefinition	Reference to the relation to one or many object occurrences that are characterized by the property set definition. A single property set can be assigned to multiple object occurrences using the objectified relationship IfcRefDefinesByProperties. IFC4-CHANGE Inverse attribute renamed from PropertyDefinitionOf with upward compatibility for file-based exchange.
Click to show 9 hidden inherited attributes
IfcPropertySet (1)
5	HasProperties	SET [1:?] OF IfcProperty	Contained set of properties. For property sets defined as part of the IFC Object model, the property objects within a property set are defined as part of the standard. If a property is not contained within the set of predefined properties, its value has not been set at this time.

Table 5.1.3.14.B

5.1.3.14.4 Formal propositions

Name	Description
ExistsName	The Name attribute has to be provided. The attribute is used to specify the signifier of the property set. The properties that are allowed to be attached to a particular property set may be given within the property set definition part of the IFC specification. Those property set definitions are references in the semantic definition section of the individual subtypes of IfcObjectDefinition.
`EXISTS(SELF\IfcRoot.Name)`
UniquePropertyNames	Every individual subtype of IfcProperty within the property set shall have a unique Name attribute value.
`IfcUniquePropertyName(HasProperties)`

Table 5.1.3.14.C

5.1.3.14.5 Concept usage

Concept	Usage	Description
IfcRoot (2)
Revision Control	General	Ownership, history, and merge state is captured using IfcOwnerHistory.
Software Identity	General	IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.
Click to show 2 hidden inherited concepts

Table 5.1.3.14.D

5.1.3.14.6 Examples

Figure 5.1.3.14.A

Linear Placement Of Signal

5.1.3.14.7 Formal representation

 ENTITY IfcPropertySet
 SUBTYPE OF (IfcPropertySetDefinition);
	HasProperties : SET [1:?] OF IfcProperty;
 WHERE
	ExistsName : EXISTS(SELF\IfcRoot.Name);
	UniquePropertyNames : IfcUniquePropertyName(HasProperties);
END_ENTITY;