IfcRelDefines

Semantic definitions at the entity

Entity definition

A generic and abstract relationship which subtypes are used to:

assign a object type to an object occurrence
assign a property set to an object instance
assign a property set template to a property set

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

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcRoot
1	GlobalId	IfcGloballyUniqueId		Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	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.	X
3	Name	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.	X
4	Description	IfcText	?	Optional description, provided for exchanging informative comments.	X
IfcRelationship
IfcRelDefines

Definitions applying to General Usage

Concept inheritance

#	Concept	Template	Model View
IfcRoot
	Identity	Software Identity	General Usage
	Revision Control	Revision Control	General 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:complexContent>

   <xs:extension base="ifc:IfcRelationship"/>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcRelDefines

 ABSTRACT SUPERTYPE OF(ONEOF(IfcRelDefinesByObject, IfcRelDefinesByProperties, IfcRelDefinesByTemplate, IfcRelDefinesByType))

 SUBTYPE OF (IfcRelationship);

END_ENTITY;

 EXPRESS-G diagram

	Definiert - Relation (allgemein)
	Rel Defines
	Définition