Wish to improve IfcCurtainWall description

[I-Sokolov]

1. Second sentence says "Curtain wall is represented as a building element assembly", suggested to change "may be represented as an assembly or single instance"

2. Needs clarification what entities can be used for curtain wall parts in case of assembly. (I did not found nothing better IfcBuildingElementPart but my user request more specific for panels and mullions, not sure what can I do)

[aothms]

Second sentence says "Curtain wall is represented as a building element assembly", suggested to change "may be represented as an assembly or single instance"

I agree. It contradicts the sentence later on. I think we can also just remove the sentence.

If the IfcCurtainWall has no components defined (empty set of SELF[IfcObject](https://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcObject.htm).IsDecomposedBy) then the IfcCurtainWall may be represented by a shape representation with the RepresentationIdentifier ='Body'.

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Needs clarification what entities can be used for curtain wall parts in case of assembly.

This has to be encoded in:

https://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/concepts/Object_Composition/Aggregation/Element_Decomposition/content.html#General-Usage

Not sure why it wasn't. Things I can think of:

• IfcMember
• IfcPlate
• IfcFastener
• IfcDoor
• IfcWindow

(what else?)