IFC (IFC4X3_ADD2) under development IfcPropertySet

RV ⓘ
AbV ⓘ 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. Entity inheritance 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,

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.

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.

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.

Click to show 9 hidden inherited attributes Click to hide 9 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 Formal propositions

Name Description

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 individal subtypes of IfcObjectDefinition.


Every individual subtype of IfcProperty within the property set shall have a unique Name attribute value.

Table 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 Click to hide 2 inherited concepts
Table Examples Formal representation

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

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Is this page difficult to understand? Let us know! Changelog IFC4

  • where rule, ExistsName
  • where rule, UniquePropertyNames
  • where rule, WR31
  • where rule, WR32