22.214.171.124.1 Semantic definition
IfcQuantityLength is a physical quantity that defines a derived length 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.
126.96.36.199.2 Entity inheritance
Name of the element quantity or measure. The name attribute has to be made recognizable by further agreements.
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.
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.
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Length measure value of this quantity.
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.
188.8.131.52.4 Formal propositions
If a unit is given, the unit type shall be a length unit.
A valid length quantity shall be greater than or equal to zero.
184.108.40.206.5 Formal representation
ENTITY IfcQuantityLength SUBTYPE OF (IfcPhysicalSimpleQuantity); LengthValue : IfcLengthMeasure; Formula : OPTIONAL IfcLabel; WHERE WR21 : NOT(EXISTS(SELF\IfcPhysicalSimpleQuantity.Unit)) OR (SELF\IfcPhysicalSimpleQuantity.Unit.UnitType = IfcUnitEnum.LENGTHUNIT); WR22 : LengthValue >= 0.; END_ENTITY;