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Hello everyone,

I'm fairly new to the world of FME, and I'm trying to do a rather complex manipulation, but which I'm sure is possible with FME. However, despite my research I can't find a solution and I need some expert advice. 

I have 2 types of input data:

  • On the one hand, railway lines as output from a ‘LineBuilder’ transformer.
  • Secondly, a digital terrain model in TIN format.

The idea would be to be able to create tunnels under the terrain. In some places, railway lines run underground in tunnels. It would be necessary to be able to ‘punch holes’ in the digital terrain model at the point of intersection. 

My initial idea was to generate 3D data around each rail line with a rectangular cross-section (5x4m) and then to be able to create an intersection between this 3D data and my digital terrain model to perform a subtraction. 

I've already tried a few things on found the net, but nothing has really worked. 

Could you give me some advice? 

Thanks in advance,

Nicolas

Hmm, well if you’re able to get a 2D polygon representing the cut in the terrain/TIN you should be able to use a Clipper to cut a hole in the TIN. You will need to make sure that your TIN in not a mesh in order to do the clip.

After the clip you will also need to retriangulate any triangles that got cut by the clip. 

This will at least achieve a hole in the TIN. I’m not really sure if this is what you’re after in the end.

What kind of platform or format are you trying to push the results to?

I think its hard. The last time I´ve tried this ( 2022 ) I came to the conclusion that FME cant cut holes in 3d in that sence.  In our example it was not possible. And I am not sure if this works today either. 

Ok,

Thank you for your answers. The problem does indeed seem very complex. But I don't despair of finding a solution. I'm sure I'm not the only one to have asked myself the question. 

To clarify, the output will be Gltf used directly in a 3D engine (Unity). 

And here's an image to give you a better idea of the problem. 


So I have my digital terrain model in the form of a TIN and the route of my railway lines. As you can see, in some places the track crosses the TIN. I'd like to be able to excavate the TIN on the basis of my track layout. 

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