Convert Topo Lines to Surface


Can anyone give me advice on how best to generate a surface from a large number of topo lines. See attached screenshot for a representation of my data.

New: TerrainMesh plugin (in alpha/beta) - Rhino / Rhino for Windows - McNeel Forum

Using the search function, you can find a lot of related topics…

If you have access to Rhino 8 WIP and the result does not need to be very accurate, you could also project the contours to a plane below all curves and loft each pair. Then mesh the breps and Shrinkwrap everything.

The Grasshopper definition attached is using the curves from @Holo file heighcurves.3dm

contours_shrinkwrap.gh (446.3 KB)

I tried to create a Point Cloud from points but couldn’t find a solution in Grasshopper.

I generally just:

  1. Select all the contour curves
  2. Use ExtractPt - make sure you set CreatePointCloud=Yes
  3. MeshPatch with the point cloud
  4. Delete the point cloud.

As contour lines don’t usually intersect the corners of the outer boundary, I also look at it and add points in the ‘corners’ at the appropriate heights where necessary before meshing to force the mesh to go all the way out to the corners.

3 Likes

Thank you Helvetosaur.

Yes, I’ve tried a similar strategy a while back, but would not have been able to summarize it so succinctly. Well said. I will try your advice. Thank you. I do work a little bit with Civil 3D and this may help simplify the process.