IfcPhysicalQuantity

BACnet MVD

#### IfcPhysicalQuantity

Natural language names

| Physikalische Größe
| Physical Quantity
| Quantité physique

##### Semantic definitions at the entity

Entity definition

The physical quantity, IfcPhysicalQuantity, is an abstract entity that holds a complex or simple quantity measure together with a semantic definition of the usage for the single or several measure value.

The Name attribute defines the actual usage or kind of measure. The interpretation of the name label has to be established within the actual exchange context. In addition an informative text may be associated to each quantity by the Description attribute.

> HISTORY New entity in IFC2x. It replaces the calcXxx attributes used in previous IFC Releases.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
1 | Name | IfcLabel |  | Name of the element quantity or measure. The name attribute has to be made recognizable by further agreements. |  | X
2 | Description | IfcText | ? | Further explanation that might be given to the quantity. |  | X

HasExternalReferences

IfcExternalReferenceRelationship
@RelatedResourceObjects

S[0:?]

Reference to an external reference, e.g. library, classification, or document information, that is associated to the quantity.

> IFC4 CHANGE New inverse attribute.

X

| PartOfComplex | IfcPhysicalComplexQuantity @HasQuantities | S[0:1] | Reference to a physical complex quantity in which the physical quantity may be contained. |  | X

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcPhysicalQuantity
1 | Name | IfcLabel |  | Name of the element quantity or measure. The name attribute has to be made recognizable by further agreements. |  | X
2 | Description | IfcText | ? | Further explanation that might be given to the quantity. |  | X

HasExternalReferences

IfcExternalReferenceRelationship
@RelatedResourceObjects

S[0:?]

Reference to an external reference, e.g. library, classification, or document information, that is associated to the quantity.

> IFC4 CHANGE New inverse attribute.

X

| PartOfComplex | IfcPhysicalComplexQuantity @HasQuantities | S[0:1] | Reference to a physical complex quantity in which the physical quantity may be contained. |  | X

##### Formal representations

XML Specification
`<xs:element name="IfcPhysicalQuantity" type="ifc:IfcPhysicalQuantity" abstract="true" substitutionGroup="ifc:Entity" nillable="true"/>
<xs:complexType name="IfcPhysicalQuantity" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:Entity">
<xs:attribute name="Name" type="ifc:IfcLabel" use="optional"/>
<xs:attribute name="Description" type="ifc:IfcText" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcPhysicalQuantity
ABSTRACT SUPERTYPE OF(ONEOF(IfcPhysicalComplexQuantity, IfcPhysicalSimpleQuantity));
Name : IfcLabel;
Description : OPTIONAL IfcText;
INVERSE
HasExternalReferences : SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects;
PartOfComplex : SET [0:1] OF IfcPhysicalComplexQuantity FOR HasQuantities;
END_ENTITY;

EXPRESS-G diagram

`

References: IfcElementQuantity IfcCostItem IfcConstructionResource IfcConstructionResourceType IfcResourceObjectSelect IfcPhysicalComplexQuantity

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