#### IfcQuantityCount

Natural language names

##### Semantic definitions at the entity

Entity definition

An physical quantity, IfcQuantityCount, that defines a derived count 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.

> EXAMPLE: An radiator may be measured according to its number of coils. The actual counting method depends on the method of measurement used.

> HISTORY New entity in IFC Release 2.x . It replaces the calcXxx attributes used in previous IFC Releases

Attribute definitions

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
4 | CountValue | IfcCountMeasure | [1:1] | Count measure value of this quantity. | X

Formal Propositions

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

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
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 | - |  | This attribute is out of scope for this model view definition and shall not be set. |
IfcPhysicalSimpleQuantity
3 | Unit | - |  | This attribute is out of scope for this model view definition and shall not be set. |
IfcQuantityCount
4 | CountValue | IfcCountMeasure | [1:1] | Count measure value of this quantity. | X

##### Formal representations

XSD Specification
`<xs:element name="IfcQuantityCount" type="ifc:IfcQuantityCount" substitutionGroup="ifc:IfcPhysicalSimpleQuantity" nillable="true"/>
<xs:complexType name="IfcQuantityCount">
<xs:complexContent>
<xs:extension base="ifc:IfcPhysicalSimpleQuantity">
<xs:attribute name="CountValue" type="ifc:IfcCountMeasure" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcQuantityCount
SUBTYPE OF (IfcPhysicalSimpleQuantity);
CountValue : IfcCountMeasure;
WHERE
WR21 : CountValue >= 0.;
END_ENTITY;

EXPRESS-G diagram

`

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