We imported the terrain data downloaded from GoogleEarth into Sketchup and created mesh data.
After that, I wanted to convert it to Surface data, but I don’t know how. How do I convert Mesh→Surface grasshopper?
If any Ray3d (Z dir) yields one ccx event with the mesh (or you can find a plane who’s Z is suitable or you can create a filter policy that could approximate things) … you can attempt to create a Patch against the mesh vertices. Mind that’s a bit slow and very sensitive to the Patch variables (may require a 2nd pass if holes are present: meaning a BrepFace as result). In general that’s not a very simple thing performance wise.
You can have a try with the rhino command “meshtonurbs”
Or with the Pufferfish component “mesh to polysurface”.
I beleive they will give the same result though.
Assuming your terrain does not have any undercuts (which it probably doesn’t coming from GoogleEarth), you can use
Drape on your mesh:
I’m not sure if this is exposed in Grasshopper/RhinoCommon. But it’d be pretty straightforward to implement something similar yourself.
Try with contour in u,v directions than use network surface
terrain.gh (9.6 KB)