Bake planar mapping to mesh

I often work with really big geographical maps (satellite orthophotos). Sometimes i have a huge and detailed texture of a whole city, and i only need a teeny tiny part for a 3D siteplan. the texture is mapped perfectly onto the site. now i have a 100 mb file with 5 mb of geometry, and 95 mb of texture. how do i apply the texture to the map, and only use the parts of the texture that are actually mapped onto the site, and get rid of the other 99% of the satellite image that isn’t used in my model?

here’s the example:

I just need to bake the texture to the geometry and throw away the original satellite orthophoto image.

Like the sketchup function “make unique texture”

Hi @user921, one way to do this with standard Rhino 7 commands is:

  1. Convert your mesh to a polysurface using _MeshToNurb
  2. Apply the same planar mapping / material to the polysurface
  3. Use _Bake which creates & assigns a new (smaller) texture and material
  4. Use _ExtractRenderMesh and apply the material to the result

Btw. step 1 works best if you add some temp geometry around your initial mesh so it forms a square. You can remove these mesh faces later after step 4.