#### IfcRelDefinesByProperties

Natural language names

##### Semantic definitions at the entity

Entity definition

This objectified relationship (IfcRelDefinesByProperties) defines the relationships between property set definitions and objects. Properties are aggregated in property sets, property sets can be grouped to define an object type.

The IfcRelDefinesByProperties is a 1-to-N relationship, as it allows for the assignment of one property set to a single or to many objects. Those objects then share the same property definition.

> HISTORY: New Entity in IFC Release 2.0. Has been renamed from IfcRelAssignsProperties in IFC Release 2x.

Attribute definitions

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
6 | RelatingPropertyDefinition | IfcPropertySetDefinition | [1:1] | Reference to the property set definition for that object or set of objects. | X

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
IfcRoot
1 | GlobalId | IfcGloballyUniqueId | [1:1] | Assignment of a globally unique identifier within the entire software world. | X
2 | OwnerHistory | IfcOwnerHistory | [1:1] | 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. | 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
5 | RelatedObjects | IfcObject | S[1:?] | Reference to the objects (or single object) to which the property definition applies. | X
IfcRelDefinesByProperties
6 | RelatingPropertyDefinition | IfcPropertySetDefinition | [1:1] | Reference to the property set definition for that object or set of objects. | X

##### Formal representations

XSD Specification
`<xs:element name="IfcRelDefinesByProperties" type="ifc:IfcRelDefinesByProperties" substitutionGroup="ifc:IfcRelDefines" nillable="true"/>
<xs:complexType name="IfcRelDefinesByProperties">
<xs:complexContent>
<xs:extension base="ifc:IfcRelDefines">
<xs:sequence>
<xs:element name="RelatingPropertyDefinition" type="ifc:IfcPropertySetDefinition" nillable="true"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcRelDefinesByProperties
SUBTYPE OF (IfcRelDefines);
RelatingPropertyDefinition : IfcPropertySetDefinition;
END_ENTITY;

EXPRESS-G diagram

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