IFC 4.3.x development IfcPropertySetDefinition

Change log


modificationsinverses PropertyDefinitionOf definitionChanged from SET OF [0:1] IfcRelDefinesByProperties FOR RelatingPropertyDefinition to SET OF [0:?] IfcTypeObject FOR HasPropertySets
modificationsinverses PropertyDefinitionOf name Changed from PropertyDefinitionOf to DefinesType Semantic definitions at the entity

IfcPropertySetDefinition is a generalization of all individual property sets that can be assigned to an object or type object. The property set definition can be either:

  • Dynamically extendable property sets - IfcPropertySet, a set of properties for which the IFC specification only provides a kind of "meta model", to be further declared by agreement. This means no entity definition of the properties exists within the IFC specification. The declaration is done by assigning a significant string value to the Name attribute of the entity as defined in the entity IfcPropertySet and at each subtype of IfcProperty, referenced by the property set. Dynamically defined property sets may have an underlying template provided by IfcPropertySetTemplate.
  • Statically defined property sets - IfcPreDefinedPropertySet, a property set entity that exists within the IFC specification. The semantic meaning of each statically defined property set is declared by its entity type and the meaning of the properties is defined by the name and data type of the explicit attribute representing it.

Property set definitions define information that is shared among multiple instances of objects, either object occurrences or object types. IfcPropertySetDefinition's (by their instantiable subtypes) can participate within the following relationships:

  • Assignment to object types - an DefinesType direct relationship to IfcTypeObject that applies the property set, with all included properties, to the object type. Those properties apply to all object occurrences having the same object type.
  • Assignment to object occurrences - an DefinesOccurrence relationship to IfcRelDefinesByProperties that applies the property set, with all included properties, to the object occurrence.

NOTE  Properties assigned to object occurrences may override properties assigned to the object type. See IfcRelDefinesByType for further information.

HISTORY  New entity in IFC2x

IFC4 CHANGE  The subtype IfcPreDefinedPropertySet has been added. Attributes

# Attribute Type Description
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 in 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.
HasContext SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions
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.
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.
DefinesOccurrenceSET [0:?] OF IfcRelDefinesByProperties FOR RelatingPropertyDefinitionReference 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. Entity inheritance

dot_inheritance IfcPreDefinedPropertySet IfcPreDefinedPropertySet IfcPropertySetDefinition IfcPropertySetDefinition IfcPreDefinedPropertySet->IfcPropertySetDefinition IfcPropertyDefinition IfcPropertyDefinition IfcPropertySetDefinition->IfcPropertyDefinition IfcPropertySet IfcPropertySet IfcPropertySet->IfcPropertySetDefinition IfcQuantitySet IfcQuantitySet IfcQuantitySet->IfcPropertySetDefinition IfcPropertyTemplateDefinition IfcPropertyTemplateDefinition IfcPropertyTemplateDefinition->IfcPropertyDefinition IfcRoot IfcRoot IfcPropertyDefinition->IfcRoot IfcObjectDefinition IfcObjectDefinition IfcObjectDefinition->IfcRoot IfcRelationship IfcRelationship IfcRelationship->IfcRoot Definitions applying to General Usage Identity

IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept. Revision Control

Ownership, history, and merge state is captured using IfcOwnerHistory. Formal representations

ENTITY IfcPropertySetDefinition
 SUBTYPE OF (IfcPropertyDefinition);
	DefinesType : SET [0:?] OF IfcTypeObject FOR HasPropertySets;
	IsDefinedBy : SET [0:?] OF IfcRelDefinesByTemplate FOR RelatedPropertySets;
	DefinesOccurrence : SET [0:?] OF IfcRelDefinesByProperties FOR RelatingPropertyDefinition;