5.1.3.35 IfcRelDecomposes

ABSTRACT This definition may not be instantiated

5.1.3.35.1 Semantic definition

The decomposition relationship, IfcRelDecomposes, defines the general concept of elements being composed or decomposed. The decomposition relationship denotes a whole/part hierarchy with the ability to navigate from the whole (the composition) to the parts and vice versa.

Decompositions may be constrained by requiring both, the whole and its parts, to be of the same type - thus establishing a nesting relationship. Or they may require some form of physical containment, thus establishing special types of aggregation relationships.

Decompositions imply a dependency, i.e. the definition of the whole depends on the definition of the parts and the parts depend on the existence of the whole. The decomposition relationship can be applied in a recursive manner, i.e. a decomposed element can be part in another decomposition. Cyclic references have to be prevented at application level.

5.1.3.35.2 Entity inheritance

- IfcRoot

5.1.3.35.3 Attributes

#	Attribute	Type	Description
IfcRoot (4)
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.

Table 5.1.3.35.A

5.1.3.35.4 Concept usage

Concept	Usage	Description
IfcRoot (2)
Revision Control	General	Ownership, history, and merge state is captured using IfcOwnerHistory.
Software Identity	General	IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.
Click to show 2 hidden inherited concepts Click to hide 2 inherited concepts

Table 5.1.3.35.B

5.1.3.35.5 Formal representation

ENTITY IfcRelDecomposes
 ABSTRACT SUPERTYPE OF (ONEOF
	(IfcRelAdheresToElement
	,IfcRelAggregates
	,IfcRelNests
	,IfcRelProjectsElement
	,IfcRelVoidsElement))
 SUBTYPE OF (IfcRelationship);
END_ENTITY;