5.1.3.24 IfcRelAssignsToGroup

5.1.3.24.1 Semantic definition

The objectified relationship IfcRelAssignsToGroup handles the assignment of object definitions (individual object occurrences as subtypes of IfcObject, and object types as subtypes of IfcTypeObject) to a group (subtypes of IfcGroup).

The relationship handles the assignment of group members to the group object. It allows for grouping arbitrary objects within a group, including other groups. The grouping relationship can be applied in a recursive manner. The resulting group is of type IfcGroup.

The inherited attribute RelatedObjects gives the references to the objects, which are the elements within the group. The RelatingGroup is the group that comprises all elements. The same object or object type can be included in zero, one or many groups. Grouping relationships are not hierarchical.

Informal Propositions:

The group assignment relationship shall be acyclic, that is, a group shall not participate in its own grouping relationship.

5.1.3.24.2 Entity inheritance

5.1.3.24.3 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.
IfcRelAssigns (2)
5	RelatedObjects	SET [1:?] OF IfcObjectDefinition	Related objects, which are assigned to a single object. The type of the single (or relating) object is defined in the subtypes of IfcRelAssigns.
6	RelatedObjectsType	OPTIONAL IfcObjectTypeEnum	Particular type of the assignment relationship. It can constrain the applicable object types, used within the role of RelatedObjects. IFC4-CHANGE The attribute is deprecated and shall no longer be used. A NIL value should always be assigned.
Click to show 6 hidden inherited attributes Click to hide 6 inherited attributes
IfcRelAssignsToGroup (1)
7	RelatingGroup	IfcGroup	Reference to group that contains all assigned group members.

Table 5.1.3.24.A

5.1.3.24.4 Formal propositions

Name	Description
NoSelfReference	The instance to with the relation points shall not be contained in the set of RelatedObjects.
`SIZEOF(QUERY(Temp <* SELF\IfcRelAssigns.RelatedObjects \| RelatingGroup :=: Temp)) = 0`

Table 5.1.3.24.B

5.1.3.24.5 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 5.1.3.24.C

5.1.3.24.6 Formal representation

ENTITY IfcRelAssignsToGroup
 SUPERTYPE OF (ONEOF
	(IfcRelAssignsToGroupByFactor))
 SUBTYPE OF (IfcRelAssigns);
	RelatingGroup : IfcGroup;
 WHERE
	NoSelfReference : SIZEOF(QUERY(Temp <* SELF\IfcRelAssigns.RelatedObjects | RelatingGroup :=: Temp)) = 0;
END_ENTITY;