8.17.2.3 IfcPhysicalSimpleQuantity

Quantité physique simple
Simple physikalische Größe

The physical quantity, IfcPhysicalSimpleQuantity, is an entity that holds a single quantity measure value (as defined at the subtypes of IfcPhysicalSimpleQuantity) together with a semantic definition of the usage for the measure value.

EXAMPLE  An element, like a wall, may have several area measures, like footprint area, left wall face area, right wall face area. These areas would be given by three instances of the area quantity subtype, with different Name string values.

A section "Quantity Use Definition" at individual entities as subtypes of IfcBuildingElement gives guidance to the usage of the Name attribute to characterize the individual quantities. If the Unit attribute is given, the value attribute (introduced at the level of subtypes of IfcPhysicalSimpleQuantity) are given as quantities of this unit, otherwise the global unit definitions (given by IfcUnitAssignment) are used.

HISTORY  New entity in IFC2x2 Addendum 1.
IFC2x2 ADDENDUM 1 CHANGE  The abstract entity IfcPhysicalSimpleQuantity has been added. Upward compatibility for file based exchange is guaranteed.

XSD Specification:

 <xs:element name="IfcPhysicalSimpleQuantity" type="ifc:IfcPhysicalSimpleQuantity" abstract="true" substitutionGroup="ifc:IfcPhysicalQuantity" nillable="true"/>
 <xs:complexType name="IfcPhysicalSimpleQuantity" abstract="true">
  <xs:complexContent>
   <xs:extension base="ifc:IfcPhysicalQuantity">
    <xs:sequence>
     <xs:element name="Unit" type="ifc:IfcNamedUnit" nillable="true" minOccurs="0"/>
    </xs:sequence>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>

EXPRESS Specification:

ENTITY IfcPhysicalSimpleQuantity
ABSTRACT SUPERTYPE OF(ONEOF(IfcQuantityArea, IfcQuantityCount, IfcQuantityLength, IfcQuantityTime, IfcQuantityVolume, IfcQuantityWeight))
SUBTYPE OF IfcPhysicalQuantity;
Unit : OPTIONAL IfcNamedUnit;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

Unit : Optional assignment of a unit. If no unit is given, then the global unit assignment, as established at the IfcProject, applies to the quantity measures.

Inheritance Graph:

ENTITY IfcPhysicalSimpleQuantity
ENTITY IfcPhysicalQuantity
Name : IfcLabel;
Description : OPTIONAL IfcText;
INVERSE
HasExternalReferences : SET OF IfcExternalReferenceRelationship FOR RelatedResourceObjects;
PartOfComplex : SET [0:1] OF IfcPhysicalComplexQuantity FOR HasQuantities;
ENTITY IfcPhysicalSimpleQuantity
Unit : OPTIONAL IfcNamedUnit;
END_ENTITY;

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