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#CV-2x3-106

agreed use of geometric representation context and sub context
number
#CV-06-106 
based on
IFC2x3
affects
extended coordination view
date
24. Feb 2006
initiator
ISG meeting in Berlin
summary agreed use of geometric representation context and subcontext

 

Description

each IFC model shall have a maximum of 2 (and minimum of 1) instances of IfcGeometricRepresentationContext. The conventions to use the ContextType attributes are:

  • IfcGeometricRepresentationContext.ContextType = 'Model' for all but annotations
  • IfcGeometricRepresentationContext.ContextType = 'Plan' for annotations

 

Differentiation of Model representation context (to allow a better structured export) is supported by using IfcGeometricRepresentationSubContext. The conventions to use the ContextType attributes are:

  • an IfcGeometricRepresentationContext.ContextType = 'Model' may have subcontexts.
    • the IfcGeometricRepresentationSubContext.ContextIdentifier should be: 'Box', 'Axis', 'FootPrint', 'Profile', 'Body'
    • it refers to the IfcShapeRepresentation.RepresentationIdentifier of the included object geometry

 

[added 05-05-2006]
Differentiation of Plan representation context (to allow a better structured export) is supported by using IfcGeometricRepresentationSubContext. The conventions to use the ContextType attributes are:

  • an IfcGeometricRepresentationContext.ContextType = 'Plan' may have subcontexts.
    • the IfcGeometricRepresentationSubContext.ContextIdentifier should be: 'Annotation'
    • required information (to allow the scaling of annotations, like line types, hatching, text) is the TargetScale attribute, it always has to be provided.
    • the TargetView attribute is always set to .PLAN_VIEW.

 

[added 06-07-2011]
The following agreement applies to the IFC2x3 CoordinationView V2.0

  • an IfcGeometricRepresentationContext with ContextType = 'Model' shall be included
  • it shall have a minimum of one sub context, being IfcGeometricRepresentationSubContext.ContextIdentifier = 'Body', and depending on the contained shape representations additional sub contexts 'Box', 'Axis', 'FootPrint', 'Profile'
  • all shape representations shall be assigned to the correct IfcGeometricRepresentationSubContext and none to the main IfcGeometricRepresentationContext