Question

How can I convert CityGML Files into clean OBJ Files?

  • 7 January 2022
  • 2 replies
  • 102 views

Hello FME-Users,

I have a problem with my CityGML Data. I want the final results to look like clean OBJ Files. When I load them into e.g. 3Ds Max they should have no errors. I also do not want faces to be seen in my 3D software. Instead I would like to see proper polygons (if quads are possible, I want to see them; they can be made out of triangles, but these triangles should be hidden).

I found this image on Wikipedia showing the different possible Elements of a mesh:

 

 Mesh_overview 

My current FME workflow looks like this:

 

workflow 

I have buildings made out of 3 elements: Groundsurface, Wallsurface and Roofsurface. I would like to bring all of these together as a mesh (with polygons). I used the GeometryCoercer to convert the rawdata into polygons. The MeshBuilder is used to create a mesh. Here I think my polygons were converted into surfaces...

Below I also provide you with my settings from the Deaggregator and the Coerser.

 

deaggregatorcoercer 

In 3Ds Max the buildings look like that:

3dsmaxthis looks really faulty... The files are not really usable in a 3d software.

 

I would be very thankful, if anybody could help me with this problem :)


2 replies

Userlevel 2
Badge +17

Hi @christianlendl​ , I think OBJ writer has a capability to aggregate automatically input surfaces/solids into a single mesh before writing. Have you tried this workflow?

citygml2obj

Hi @Takashi Iijima​ , thank you very much for your fast reply!

Yes I have tried this workflow as well. Unfortunately the results are not really different from the workflow before...

In the viewport of FME everything seems to be fine, but when I open the files with 3Ds Max, they still look very faulty.

fme_testhere I have the view from FME.

 

And here from inside 3DsMax...

3dsmax_new 

Something has to be very wrong with the files, because I can open any other obj file (not generated with FME) and everything seems normal in 3Ds Max.

 

Thank you very much for your help in advance!

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