#### 5.1.3.27 IfcRelDefines

| Définition
| Definiert - Relation (allgemein)

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.

XSD 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, IfcRelDefinesByType))

| SUBTYPE OF (IfcRelationship);

END_ENTITY;

Inheritance Graph:

ENTITY IfcRelDefines

| ENTITY IfcRoot

GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | OPTIONAL IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;

| ENTITY IfcRelationship

| ENTITY IfcRelDefines

END_ENTITY;

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