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IfcReferenceFace

Definition from IAI: The IfcReferenceFace provides a face information as topological reference for a products' shape. In addition the face can refer to a surface, which defines a reference surface in space.

The reference geometry is given for potential use in future extensions of IFC.

HISTORY New entity in IFC Release 1.5. Has been renamed from IfcReferenceSurface in IFC 2x.
ISSUE: See issues for changes made in IFC Release 2x.

EXPRESS specification:

ENTITY IfcReferenceFace
SUBTYPE OF ( IfcReferenceGeometry);
Face  :  IfcFace;
WHERE
WR1  :  EXISTS(SELF\IfcReferenceGeometry.Placement) OR (NOT('IFCTOPOLOGYRESOURCE.IFCFACESURFACE' IN TYPEOF(Face)));
END_ENTITY;

Attribute definitions:

Face  :  3D geometric Surface.

Formal Propositions:

WR1  :  A placement should be given if the face is expressed by a face surface.

References (1):

Name Type Referred through Express-G
IfcReferenceGeometry Entity
Subtype
Diagram 1

Inheritance graph

ENTITY IfcReferenceFace;
ENTITY IfcReferenceGeometry;
Placement  :  OPTIONAL IfcAxis2Placement;
ENTITY IfcReferenceFace;
Face  :  IfcFace;
END_ENTITY;