8.17.3.4 IfcQuantityArea
8.17.3.4.1 Semantic definition
IfcQuantityArea is a physical quantity that defines a derived area measure to provide an element's physical property. It is normally derived from the physical properties of the element under the specific measure rules given by a method of measurement.
8.17.3.4.2 Entity inheritance
8.17.3.4.3 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. |
|
| PartOfComplex | SET [0:1] OF IfcPhysicalComplexQuantity FOR HasQuantities |
Reference to a physical complex quantity in which the physical quantity may be contained. |
|
| 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. |
| Click to show 5 hidden inherited attributes Click to hide 5 inherited attributes | |||
| IfcQuantityArea (2) | |||
| 4 | AreaValue | IfcAreaMeasure |
Area measure value of this quantity. |
| 5 | Formula | OPTIONAL IfcLabel |
A formula by which the quantity has been calculated. It can be assigned in addition to the actual value of the quantity. Formulas could be mathematic calculations (like width x height), database links, or a combination. The formula is for informational purposes only. |
8.17.3.4.4 Formal propositions
| Name | Description |
|---|---|
| WR21 |
If a unit is given, the unit type shall be area unit. |
|
|
| WR22 |
A valid area quantity shall be greater than or equal to zero. |
|
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8.17.3.4.5 Formal representation
ENTITY IfcQuantityArea
SUBTYPE OF (IfcPhysicalSimpleQuantity);
AreaValue : IfcAreaMeasure;
Formula : OPTIONAL IfcLabel;
WHERE
WR21 : NOT(EXISTS(SELF\IfcPhysicalSimpleQuantity.Unit)) OR
(SELF\IfcPhysicalSimpleQuantity.Unit.UnitType = IfcUnitEnum.AREAUNIT);
WR22 : AreaValue >= 0.;
END_ENTITY;