Natural language names
Definiert - Relation (allgemein)
Rel Defines
Semantic definitions at the entity
Entity definition

A generic and abstract relationship which subtypes are used to:

EXAMPLE  Several instances of windows within the IFC project model may be of the same (catalogue or manufacturer) type. Thereby they share the same properties. This relationship is established by the subtype IfcRelDefinesByType of IfcRelDefines relationship assigning an IfcWindowStyle to multiple occurrences IfcWindow.
EXAMPLE  The (same) property set, e.g.  Pset_ProductManufacturerInfo, keeping the manufacturer name, label and production year of a product, can be assigned to one, or many instances of furnishing. This relationship is established by the subtype IfcRelDefinesByProperties of IfcRelDefines relationship assigning an IfcPropertySet to one or more instances of IfcFurnishingElement.
HISTORY  New entity in IFC2x.
IFC4 CHANGE  The attribute RelatedObjects had been demoted to the subtypes IfcRelDefinesByProperties and IfcRelDefinesByType.
Inherited definitions from supertypes
Entity inheritance IfcRelDefinesByObject IfcRelDefinesByProperties IfcRelDefinesByTemplate IfcRelDefinesByType IfcRelationship 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="IfcRelDefines" type="ifc:IfcRelDefines" abstract="true" substitutionGroup="ifc:IfcRelationship" nillable="true"/>
 <xs:complexType name="IfcRelDefines" abstract="true">
   <xs:extension base="ifc:IfcRelationship"/>
EXPRESS Specification
ENTITY IfcRelDefines
 ABSTRACT SUPERTYPE OF(ONEOF(IfcRelDefinesByObject, IfcRelDefinesByProperties, IfcRelDefinesByTemplate, IfcRelDefinesByType))
 SUBTYPE OF (IfcRelationship);

Link to EXPRESS-G diagram EXPRESS-G diagram

Link to this page  Link to this page