Natural language names
Objektifizierte Relation (allgemein)
Semantic definitions at the entity
Entity definition

IfcRelationship is the abstract generalization of all objectified relationships in IFC. Objectified relationships are the preferred way to handle relationships among objects. This allows to keep relationship specific properties directly at the relationship and opens the possibility to later handle relationship specific behavior.

There are two different types of relationships, 1-to-1 relationships and 1-to-many relationship. used within the subtypes of IfcRelationship. The following convention applies to all subtypes:

HISTORY  New entity in IFC1.0.
Inherited definitions from supertypes
Entity inheritance IfcRelAssigns IfcRelAssociates IfcRelConnects IfcRelDeclares IfcRelDecomposes IfcRelDefines IfcRoot
Attribute inheritance
1GlobalIdIfcGloballyUniqueId Assignment of a globally unique identifier within the entire software world. X
2OwnerHistoryIfcOwnerHistory? 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.
3NameIfcLabel? 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. X
4DescriptionIfcText? Optional description, provided for exchanging informative comments.X
Definitions applying to General Usage

Concept inheritance

#ConceptTemplateModel View
IdentitySoftware IdentityGeneral Usage
Revision ControlRevision ControlGeneral Usage
Formal representations
XML Specification
 <xs:element name="IfcRelationship" type="ifc:IfcRelationship" abstract="true" substitutionGroup="ifc:IfcRoot" nillable="true"/>
 <xs:complexType name="IfcRelationship" abstract="true">
   <xs:extension base="ifc:IfcRoot"/>
EXPRESS Specification
ENTITY IfcRelationship
 ABSTRACT SUPERTYPE OF(ONEOF(IfcRelAssigns, IfcRelAssociates, IfcRelConnects, IfcRelDeclares, IfcRelDecomposes, IfcRelDefines))
 SUBTYPE OF (IfcRoot);

Link to EXPRESS-G diagram EXPRESS-G diagram

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