#### 8.9.3.7 IfcUnitAssignment

| Assignation d'unité
| Einheit - Zuweisung

IfcUnitAssignment indicates a set of units which may be assigned. Within an IfcUnitAssigment each unit definition shall be unique; that is, there shall be no redundant unit definitions for the same unit type such as length unit or area unit. For currencies, there shall be only a single IfcMonetaryUnit within an IfcUnitAssignment.

> NOTE A IfcProject has a unit assignment which establishes a set of units which will be used globally within the project, if not otherwise defined. Other objects may have local unit assignments if there is a requirement for them to make use of units which do not fall within the project unit assignment.

> HISTORY New entity in IFC1.5.1.

XSD Specification:

<xs:element name="IfcUnitAssignment" type="ifc:IfcUnitAssignment" substitutionGroup="ifc:Entity" nillable="true"/>
<xs:complexType name="IfcUnitAssignment">
<xs:complexContent>
<xs:extension base="ifc:Entity">
<xs:sequence>
<xs:element name="Units">
<xs:complexType>
<xs:group ref="ifc:IfcUnit" maxOccurs="unbounded"/>
<xs:attribute ref="ifc:itemType" fixed="ifc:IfcUnit"/>
<xs:attribute ref="ifc:cType" fixed="set"/>
<xs:attribute ref="ifc:arraySize" use="optional"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>

EXPRESS Specification:

ENTITY IfcUnitAssignment;

Units | : | SET [1:?] OF IfcUnit;

| WHERE

WR01 | : | IfcCorrectUnitAssignment(Units);

END_ENTITY;

Attribute Definitions:

Units | : | Units to be included within a unit assignment.

Formal Propositions:

WR01 | : | Checks that the set of globally assigned units has each unit type (either of type IfcNamedUnit,IfcDerivedUnit, or IfcMonetaryUnit) defined only once.

Inheritance Graph:

ENTITY IfcUnitAssignment

| ENTITY IfcUnitAssignment

Units | : | SET [1:?] OF IfcUnit;

END_ENTITY;

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