IfcRelDefinesByObject

Item	SPF	XML	Change	Description
IFC2x3 to IFC4
IfcRelDefinesByObject			ADDED

Semantic definitions at the entity

Entity definition

The objectified relationship IfcRelDefinesByObject defines the relationship between an object taking part in an object type decomposition and an object occurrences taking part in an occurrence decomposition of that type.

The IfcRelDefinesByObject is a 1-to-N relationship, as it allows for the assignment of one declaring object information to a single or to many reflected objects. Those objects then share the same object property sets and, for subtypes of IfcProduct, the eventually assigned representation maps.

Only objects that take part in a type decomposition and in an occurrence decomposition of the same type can be connected by the IfcRelDefinesByObject relationship. The IfcRelDefinesByObject links the decomposed object type part, also called the "declaring part" with the occurrence of that part inside the occurrence of the decomposed type, also called the "reflected part", as shown in Figure 123.

Figure 123 — Part definition relationships

The IfcRelDefinesByObject can be used together with the shape representations of the product type as shown in Figure 124. The IfcShapeRepresentation of the "declaring part" is referenced by the "reflected part". The IfcObjectPlacement of the model occurrence (the whole) determines the position within the project context.

Figure 124 — Part definition relationships with shape representation

HISTORY New entity in IFC4.

Attribute definitions

#	Attribute	Type	Cardinality	Description	C
5	RelatedObjects	IfcObject	S[1:?]	Objects being part of an object occurrence decomposition, acting as the "reflecting parts" in the relationship.	X
6	RelatingObject	IfcObject	[1:1]	Object being part of an object type decomposition, acting as the "declaring part" in the relationship.	X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	C
IfcRoot
1	GlobalId	IfcGloballyUniqueId	[1:1]	Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	[0:1]	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.	X
3	Name	IfcLabel	[0:1]	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	[0:1]	Optional description, provided for exchanging informative comments.	X
IfcRelationship
IfcRelDefines
IfcRelDefinesByObject
5	RelatedObjects	IfcObject	S[1:?]	Objects being part of an object occurrence decomposition, acting as the "reflecting parts" in the relationship.	X
6	RelatingObject	IfcObject	[1:1]	Object being part of an object type decomposition, acting as the "declaring part" in the relationship.	X

Definitions applying to Common Use Definitions

Concept inheritance

#	Concept	Model View
IfcRoot
	Software Identity	Common Use Definitions
	Revision Control	Common Use Definitions

Formal representations

XSD Specification

 <xs:element name="IfcRelDefinesByObject" type="ifc:IfcRelDefinesByObject" substitutionGroup="ifc:IfcRelDefines" nillable="true"/>

 <xs:complexType name="IfcRelDefinesByObject">

  <xs:complexContent>

   <xs:extension base="ifc:IfcRelDefines">

    <xs:sequence>

     <xs:element name="RelatedObjects">

      <xs:complexType>

       <xs:sequence>

        <xs:element ref="ifc:IfcObject" maxOccurs="unbounded"/>

       </xs:sequence>

       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcObject"/>

       <xs:attribute ref="ifc:cType" fixed="set"/>

       <xs:attribute ref="ifc:arraySize" use="optional"/>

      </xs:complexType>

     </xs:element>

     <xs:element name="RelatingObject" type="ifc:IfcObject" nillable="true"/>

    </xs:sequence>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcRelDefinesByObject

 SUBTYPE OF (IfcRelDefines);

  RelatedObjects : SET [1:?] OF IfcObject;

  RelatingObject : IfcObject;

END_ENTITY;

 EXPRESS-G diagram

Link to this page

	Definiert durch Objekte - Relation
	Rel Defines By Object
	Définition par objet