8.17.3.3 IfcPhysicalSimpleQuantity
ABSTRACT This definition may not be instantiated
8.17.3.3.1 Semantic definition
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.
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 IfcBuiltElement 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.
New entity in IFC2x2 Addendum 1. 1 CHANGE The abstract entity IfcPhysicalSimpleQuantity has been added. Upward compatibility for file based exchange is guaranteed.8.17.3.3.2 Entity inheritance
8.17.3.3.3 Attributes
| # | Attribute | Type | Description |
|---|---|---|---|
| IfcPhysicalQuantity (4) | |||
| 1 | Name | IfcLabel |
Name of the element quantity or measure. The name attribute has to be made recognizable by further agreements. |
| 2 | Description | OPTIONAL IfcText |
Further explanation that might be given to the quantity. |
| HasExternalReferences | SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects |
Reference to an external reference, e.g. library, classification, or document information, that is associated to the quantity. New inverse attribute. |
|
| PartOfComplex | SET [0:1] OF IfcPhysicalComplexQuantity FOR HasQuantities |
Reference to a physical complex quantity in which the physical quantity may be contained. |
|
| Click to show 4 hidden inherited attributes Click to hide 4 inherited attributes | |||
| IfcPhysicalSimpleQuantity (1) | |||
| 3 | Unit | OPTIONAL IfcNamedUnit |
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. |
8.17.3.3.4 Formal representation
ENTITY IfcPhysicalSimpleQuantity
ABSTRACT SUPERTYPE OF (ONEOF
(IfcQuantityArea
,IfcQuantityCount
,IfcQuantityLength
,IfcQuantityNumber
,IfcQuantityTime
,IfcQuantityVolume
,IfcQuantityWeight))
SUBTYPE OF (IfcPhysicalQuantity);
Unit : OPTIONAL IfcNamedUnit;
END_ENTITY;