IfcQuantityCount

IfcQuantityCount是一个物理量,它定义一个派生的计数度量来提供元素的物理属性。它通常由测量方法给出的特定测量规则下元素的物理性质导出。

 

例如,可以根据散热器的线圈数来测量散热器。实际的计数方法取决于所用的测量方法。

IFC2x中增加的新实体。它替换了以前IFC版本中使用的calcXxx属性。

 

Formal Propositions

Rule Description
WR21 The value of the count shall be greater than or equal to zero.
 

 

 

IfcQuantityCount

 

 

 

Attribute inheritance

# Attribute Type Cardinality Description C
IfcPhysicalQuantity
1 Name IfcLabel [1:1] Name of the element quantity or measure. The name attribute has to be made recognizable by further agreements. X
2 Description IfcText [0:1] 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. X
  PartOfComplex IfcPhysicalComplexQuantity
@HasQuantities
S[0:1] Reference to a physical complex quantity in which the physical quantity may be contained. X
IfcPhysicalSimpleQuantity
3 Unit IfcNamedUnit [0:1] 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. X
IfcQuantityCount
4 CountValue IfcCountMeasure [1:1] Count measure value of this quantity. X
5 Formula IfcLabel [0:1] 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. X
 

EXPRESS Specification

ENTITY IfcQuantityCount
 SUBTYPE OF (IfcPhysicalSimpleQuantity);
  CountValue : IfcCountMeasure;
  Formula : OPTIONAL IfcLabel;
 WHERE
  WR21 : CountValue >= 0.;
END_ENTITY;

 

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