#### IfcNamedUnit

Natural language names

##### Semantic definitions at the entity

Entity definition

Definition from ISO/CD 10303-41:1992: A named unit is a unit quantity associated with the word, or group of words, by which the unit is identified.

> NOTE Corresponding STEP name: named_unit, please refer to ISO/IS 10303-41:1994 for the final definition of the formal standard.

> HISTORY New type in IFC Release 1.5.1.

Attribute definitions

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
1 | Dimensions | IfcDimensionalExponents | [1:1] | The dimensional exponents of the SI base units by which the named unit is defined. | X
2 | UnitType | IfcUnitEnum | [1:1] | The type of the unit. | X

Formal Propositions

Rule | Description
--- | ---
WR1 | Correct dimensions of the unit are established through the function IfcCorrectDimensions.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
IfcNamedUnit
1 | Dimensions | IfcDimensionalExponents | [1:1] | The dimensional exponents of the SI base units by which the named unit is defined. | X
2 | UnitType | IfcUnitEnum | [1:1] | The type of the unit. | X

##### Formal representations

XSD Specification
`<xs:element name="IfcNamedUnit" type="ifc:IfcNamedUnit" abstract="true" substitutionGroup="ifc:Entity" nillable="true"/>
<xs:complexType name="IfcNamedUnit" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:Entity">
<xs:sequence>
<xs:element name="Dimensions" type="ifc:IfcDimensionalExponents" nillable="true" minOccurs="0"/>
</xs:sequence>
<xs:attribute name="UnitType" type="ifc:IfcUnitEnum" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcNamedUnit
ABSTRACT SUPERTYPE OF(ONEOF(IfcConversionBasedUnit, IfcSIUnit));
Dimensions : IfcDimensionalExponents;
UnitType : IfcUnitEnum;
WHERE
WR1 : IfcCorrectDimensions (SELF.UnitType, SELF.Dimensions);
END_ENTITY;

EXPRESS-G diagram

`

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