IfcDimensionCount

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

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