#### IfcDimensionCount

Natural language names

##### Semantic definitions at the type

Type definition

Definition from ISO/CD 10303-42:1992: A dimension count is a positive integer used to define the coordinate space dimensionality.

The IfcDimensionCount is restricted to have the dimensionality of either 1, 2, or 3 - the WR1 had been added as an addition to the STEP P42 entity dimension_count. In contrary to the STEP P42 constraint, that all geometric representation items within a geometric representation context are forced to have the same dimension count, the IFC geometry allows mixed dimensions, particularly when defining the boundary of planar surfaces.

> NOTE Corresponding STEP type: dimension_count, please refer to ISO/IS 10303-42:1994, p. 14 for the final definition of the formal standard.

> HISTORY New Type in IFC Release 1.5

Formal Propositions

Rule | Description
--- | ---
WR1 | The dimension count should be an integer between 1 and 3 NOTE: This is a further constraint by IFC, the upper limit does not exist in STEP.

##### Formal representations

XSD Specification
`<xs:simpleType name="IfcDimensionCount">
<xs:restriction base="xs:long"/>
</xs:simpleType>
<xs:element name="IfcDimensionCount-wrapper" nillable="true">
<xs:complexType>
<xs:simpleContent>
<xs:extension base="ifc:IfcDimensionCount">
<xs:attributeGroup ref="ifc:instanceAttributes"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
</xs:element>
`
EXPRESS Specification
`TYPE IfcDimensionCount = INTEGER;
WHERE
WR1 : { 0 < SELF <= 3 }
END_TYPE;

EXPRESS-G diagram

`

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