IfcRelDefines

BACnet MVD

#### IfcRelDefines

Natural language names

| Definiert - Relation (allgemein)
| Rel Defines
| Définition

##### 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 | 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
IfcRelDefines

##### 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="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

`

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