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Transformation of LOD2 3D-Multipatch (fGDB) to CityGML

  • June 9, 2026
  • 3 replies
  • 36 views

melri
Contributor
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Hi,

I’m currently struggling to figure out how to convert a LOD2 3D-Multipatch from a FileGDB into CityGML. I do currently not have a program avail

able to open or edit CityGML files, but it might be important at a later stage to be able to convert the data back into CityGML. Is it generally possible to convert any multipatch into a CityGML file at a later stage, or is important information lost in the process?

How do I ensure that a distinction is made between Wall, Roof, Ground, and Closure Surface? Or is it all simply classified as Building?

I've already looked at the website Writing CityGML from FME, but unfortunately, I still don't know how to proceed. How do I know which ‘citygml_lod_name’ value to use? If multiple values ​​yield a result, should I use all of them parallel?

I would be grateful for any tips to help me understand this better…

Thank you!

 

My first attempt of a workbench...

 

3 replies

daveatsafe
Safer
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  • Safer
  • June 10, 2026

Hi ​@melri,

If you would like to share your source data, I would be happy to create an annotated workspace to convert it to CityGML for you. This is the best way to learn how to create CityGML files, which can be a little complex. If you don’t want to share your data publicly, you can send me a download link at dave.campanas@safe.com.


melri
Contributor
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  • Author
  • Contributor
  • June 11, 2026

Hi daveatsafe,

thank you so much for offering to help! I just sent you a download link to your mailaddress.

 


daveatsafe
Safer
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  • Safer
  • June 24, 2026

Hi ​@melri 

Please try the attached workspace. It uses the surface normals generated by the PlanarityFilter transformer to distinguish between Roof (normal Z component positive), Ground (normal Z component negative) and Wall (normal Z component 0) surfaces.