Question

Surface modeller - Generate TIN in a tunnel

  • 26 January 2017
  • 3 replies
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Hi Fme:rs,

Working on a TIN modell from Lidar data in a tunnel. Anybody knows how to avoid the surfacemodeller to create triangels where z differs a lot? For examaple the opening. Cant find that parameter.

/cheers Henrik


3 replies

Userlevel 4

Have you tried using breaklines at the openings?

Userlevel 2
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Hi @hrinze, the point would be how to determine which triangles should be discarded. For example, if the tunnel is straight and parallel to the X axis, you can compute Min/Max X for each individual triangle and then discard triangles whose Max X < (Min X of Tunnel + Tolerance) or Min X > (Max X of Tunnel - Tolerance). See also the attached example (FME 2016.1.3): tunnel-tin.fmw

It's an example for a special condition. The actual criteria should be more complex depending on the data condition, but I think that it can be found if you investigate the data carefully.

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Hi @hrinze, the point would be how to determine which triangles should be discarded. For example, if the tunnel is straight and parallel to the X axis, you can compute Min/Max X for each individual triangle and then discard triangles whose Max X < (Min X of Tunnel + Tolerance) or Min X > (Max X of Tunnel - Tolerance). See also the attached example (FME 2016.1.3): tunnel-tin.fmw

It's an example for a special condition. The actual criteria should be more complex depending on the data condition, but I think that it can be found if you investigate the data carefully.

@takashi, Thanks for the input and .fmw. This can be a good approach. However a tunnel in the mountain is not straight and neither are the walls plain. But this can be a good start so I will give it a try with proper data

 

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