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.
Question
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
+21- Safer
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.
+35- Celebrity
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.
kailinatsafe wrote:
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.
virtualcitymatt wrote:
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.
Do you think it's possible with FME? The university is focusing on this platform a lot and it would pave the way for further utilization of software and it would be a great asset for me at this stressful time.
ershadmapper wrote:
Thank you so much for your assistance.
Thank you very much, I looked at that webinar, But can not serve my purpose yet. I really appreciate your help and attention, let's see, I mentioned bellow the detail of what exactly I look to solve with FME and hoping that some can give me a good idea or support here.
+35- Celebrity
ershadmapper wrote:
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.
Do you think it's possible with FME? The university is focusing on this platform a lot and it would pave the way for further utilization of software and it would be a great asset for me at this stressful time.
If any tool could do the translation it would be FME. There's nothing really that I know of which can do it. Identifying the external walls is pretty tricky. There are a couple of tricks but nothing is really full proof. And then you still have to deal with the roof.
How much control do you have over the ICF itslef? Are you able to lable or apply some kind of unique material to the exterior walls before exporting to IFC?
ershadmapper wrote:
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.
Do you think it's possible with FME? The university is focusing on this platform a lot and it would pave the way for further utilization of software and it would be a great asset for me at this stressful time.
Thank you For your answer.
Yes, I have control over IFC and I can change anything I want and then export to IFC. The problem is extracting only the Exterior face without any thickness for the wall, roof, and ground surface. and then I should extract other information from BIM and then Add it to my citygml as an extension property.
ershadmapper wrote:
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.
Do you think it's possible with FME? The university is focusing on this platform a lot and it would pave the way for further utilization of software and it would be a great asset for me at this stressful time.
Just as an example to mention, others use Sketchup to create a 3D building model without thickness, then translate it to CityGML and extend it with 3DcityDB for energy. Here, since I have BIM, I need to experiment with FME ow to get extended citygml LOD2 directly from IFC.
+35- Celebrity
ershadmapper wrote:
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.
Do you think it's possible with FME? The university is focusing on this platform a lot and it would pave the way for further utilization of software and it would be a great asset for me at this stressful time.
One thing which you could try is to give all the exterior roof and wall surfaces a material which you can then test for. I'm not sure if this is possible in the tool you're using. The problem really is just this is very tricky.
Some tools which you can try with Geometry tricks:
- GeometryCoercer (Lets to move a solid to a CompositeSurface
- Deaggregator (splits up the geometries into components/individual surface)
- 2DForcer (will let you then perform 2D operations like Dissolve, clip and intersections
- GeometryExtractor/Replacer (Can be used in conjunction to preserve original geometries)
- SolidDissolver (If you're lucky you can just try and dissolve the whole object into one solid)
- Dissolver (In 2D you can try and dissolve everything together to get the 2D border of the footprint, this could be intersected with the exterior wall surfaces
Just a few tools which might help. Sadly so far there really is no size fits all
Reply
Rich Text Editor, editor1
Editor toolbars
Press ALT 0 for help
Helpful Members This Week
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.