IfcRelAssignsToGroup

BACnet MVD

#### IfcRelAssignsToGroup

Natural language names

| Weist Gruppe zu - Relation
| Rel Assigns To Group
| Assignation à groupe

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcRelAssignsToGroup |  |  |  |
OwnerHistory |  |  | MODIFIED | Instantiation changed to OPTIONAL.

##### Semantic definitions at the entity

Entity 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.

> NOTE Examples of groups include zones as a grouping of spaces, distribution systems as a grouping of building service components, or structural analysis models as a grouping of structural items.

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:

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

> HISTORY New entity in IFC1.0. It has been renamed from IfcRelGroups in IFC2x.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
7 | RelatingGroup | IfcGroup |  | Reference to group that contains all assigned group members. |  | X

Formal Propositions

Rule | Description
--- | ---
NoSelfReference | The instance to with the relation points shall not be contained in the set of RelatedObjects.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcRoot
1 | GlobalId | IfcGloballyUniqueId |  | Assignment of a globally unique identifier within the entire software world. | X | 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

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 | X
4 | Description | IfcText | ? | Optional description, provided for exchanging informative comments. |  | X
IfcRelationship
IfcRelAssigns
5 | RelatedObjects | IfcObjectDefinition | S[1:?] | Related objects, which are assigned to a single object. The type of the single (or relating) object is defined in the subtypes of IfcRelAssigns. |  | X

6

RelatedObjectsType

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.

X

IfcRelAssignsToGroup
7 | RelatingGroup | IfcGroup |  | Reference to group that contains all assigned group members. |  | X

##### Definitions applying to Design Transfer View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Definitions applying to BACnet View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Formal representations

XML Specification
`<xs:element name="IfcRelAssignsToGroup" type="ifc:IfcRelAssignsToGroup" substitutionGroup="ifc:IfcRelAssigns" nillable="true"/>
<xs:complexType name="IfcRelAssignsToGroup">
<xs:complexContent>
<xs:extension base="ifc:IfcRelAssigns">
<xs:sequence>
<xs:element name="RelatingGroup" type="ifc:IfcGroup" nillable="true"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcRelAssignsToGroup
SUPERTYPE OF(IfcRelAssignsToGroupByFactor)
SUBTYPE OF (IfcRelAssigns);
RelatingGroup : IfcGroup;
WHERE
NoSelfReference : SIZEOF(QUERY(Temp <* SELF\IfcRelAssigns.RelatedObjects | RelatingGroup :=: Temp)) = 0;
END_ENTITY;

EXPRESS-G diagram

`

References: IfcGroup

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