Question

how to define and write IfcShapeRepresentation properties?

  • 15 October 2019
  • 3 replies
  • 6 views

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Hi, i'm trying to define and write IfcShapeRepresentation properties (attributes) like the RepresentationType and RepresentationIdentifier for geometries (2D points) in IfcBuildingElementProxy (class) , but unfortunately without success.

So how to define and write a 2d point in IfcBuildingElementProxy classe?

 

According the IFC definitioin (link below) i have to define the RepresentationType as "GeometricSet" and the RepresentationIdentifier as "FootPrint" for defining a 2D point

https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/FINAL/HTML/ifcproductextension/lexical/ifcbuildingelementproxy.htm

 

By following your "AutoCAD to IFC Conversion Example" Tutorial i have to set the geometry name to "FootPrint" (what defines the RepresentationIdentifier) with the GeometryPropertySetter-Transformer. (see workspace below)

Now, how to set the RepresentationType as "GeometricSet"? (A "normal" point geometry like fme_point do not be written in the IFC file!)

Non geometry was exported in the example below...

 

And second, as you explaind in the FME Dokumentation (see link and screenshot below), there are to ways to define/set the RepresentationIdentifier. How to set the RepresentationIdentifier by using the ifc_presentation_identifier trait?

http://docs.safe.com/fme/html/FME_Desktop_Documentation/FME_ReadersWriters/ifc/IFC_writer.htm

 

Thanks for your help.

 

Best Regard

 

LuHu

3 replies

Userlevel 2
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Hi @luhu,

Please have a look at the IFC writer parameters for Representation Contexts, then add the Footprint context (Type: Model, Identifier: Footprint, Geometry Types: Curves).

With both the Representation Context parameter and geometry name set, FME should be able to handle writing the appropriate geometry settings.

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Hi @daveatsafe

Thanks for the quick reply.

But i set already both the Representation Context and the geometry name, and it did not works! No geometric elements are exportet...see IFC in the question.

(sorry i forgot to mention that i had set the Representation Context parameters)

 

As i understand the geometric Representation of the IfcBuildingElementProxy class, i have to set de RepresentationType as "GeometricSet". (see below)

https://standards.buildingsmart.org/IFC/RELEASE/IFC2x3/FINAL/HTML/ifcproductextension/lexical/ifcbuildingelementproxy.htm

-->> How to set the RepresentationType as "GeometrcSet" in FME?

 

 

What is also of interest...

-->> How to set the RepresentationIdentifier by using the ifc_presentation_identifier trait? (see question)

 

 

Thanks for your help.

Best Regard

 

LuHu
Userlevel 2
Badge +17

Hi @luhu,

I think that Footprints can only be curves, not points. This is all that FME allows. I am attaching a workspace illustrating how to create a Footprint representation for IfcBuildingElementProxy.

Create_Footprint.fmw

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