Is there any way to extract only the exterior wall boundary along with its door, window, and other related elements? Please share some ideas I really appreciate your kind support.

Hello everyone, for my thesis, I need to get CityGML LOD1 to LOD4 from IFC and utilize it for energy analysis related to heat demand. I have attempted to use pre-existing workspaces, but I need to extract exterior walls and elements which I can not

Hello @ershadmapper, thanks for posting to the FME Community. I want to prefice that I am not overly familiar with IFC and geometry extraction.

If you use the IFC with Data Views Reader, I think there is a parameter you can set to extract the buildings shell or body on read:

If this doesn't produce desired results, I think you should test the GeometryPartExtractor. This transformer will extract selected geometry parts based on a Geometry XQuery. You can find Geometry Traits and Attributes in the Feature Information window, by inspecting a feature. If you're using a Xquery, and still seeing all geometry being passed, you may need to Deaggregate first. Dave goes over this transformer and an example of how to use it in this 3D webinar (at around 16 minutes). Otherwise, check out this article, which you may be able to steal concepts/logic from. Other ideas welcomed! Happy to help, Kailin.

This is just a really hard thing to do - so far as I know no one has been able to solve the problem of ICF to CityGML in a generic kind of way unless the IFC files follow certain conventions. Do you have any control over the IFC files or their structure? CityGML 3 has created to make such conversions more simple. I believe CityGML 3 supports solid walls.

Hello @ershadmapper, thanks for posting to the FME Community. I want to prefice that I am not overly familiar with IFC and geometry extraction.

If you use the IFC with Data Views Reader, I think there is a parameter you can set to extract the buildings shell or body on read:

If this doesn't produce desired results, I think you should test the GeometryPartExtractor. This transformer will extract selected geometry parts based on a Geometry XQuery. You can find Geometry Traits and Attributes in the Feature Information window, by inspecting a feature. If you're using a Xquery, and still seeing all geometry being passed, you may need to Deaggregate first. Dave goes over this transformer and an example of how to use it in this 3D webinar (at around 16 minutes). Otherwise, check out this article, which you may be able to steal concepts/logic from. Other ideas welcomed! Happy to help, Kailin.

Thank you so much for your assistance.

This is just a really hard thing to do - so far as I know no one has been able to solve the problem of ICF to CityGML in a generic kind of way unless the IFC files follow certain conventions. Do you have any control over the IFC files or their structure? CityGML 3 has created to make such conversions more simple. I believe CityGML 3 supports solid walls.

Thanks for the information. My goal is to generate LOD2 and LOD3 from IFC for building energy analysis. I need to map it to a valid XML schema cityGML LOD2 for Simstadt software. I've been working on this for a long but I ended up confused. the available FME workspaces can translate IFC to CityGML LOD4, but I only need the exterior faces of the building as wall surfaces, the top floor face as the roof, and the ground face as a ground surface for LOD2. additionally, I need to add information such as thermal zone, parameters like volumes, wall dimensions, types, analytical parameters, and other required information from the IFC file.