CV-2x3-106 (aka CV-06-106)

Agreed use of geometric representation context and sub context [modified 2006-05-05 & 2011-06-07]

Based on          IFC2x3

Initiator            ISG Meeting-Berlin

Effects              Extended Coordination View

Date                    2006 02 24

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.

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