Decimate a mesh

[yw5aj]

Hi Mike,

(I assume this would be a simple question :)

Would there be any simple way to decimate a mesh? Say, simplify the geometry from 10,000 faces to 1,000 faces?

Thanks!

Shawn

[mikedh]

Hey Shawn- at the moment Trimesh doesn't implement any simplification algorithms- I've been meaning to implement quadratic edge collapse decimation for a while, but never had time. If you want to implement it PR's would be accepted gladly :). In the meantime you're probably best off calling meshlabserver with subprocess.check_call or something.

[yw5aj]

Hi Mike,

Thanks for your response! And the quadratic edge collapse decimation looks really interesting. I'll read more into it - I'm not sure whether the complexity is within my coding capabilities :P

And thank you also for your suggestion to use meshlabserver! I noticed that blender also has a decimate modifier, so I can try to see whether that's callable via command line.

Shawn

[Marviel]

This code sample looks like it does the meshlabserver trick: https://gist.github.com/awesomebytes/a3bc8729d0c1d0a9499172b9a77d2622

[mikedh]

It would be neat to make a nice cython wrapper then set up cibuildwheel on: https://github.com/sp4cerat/Fast-Quadric-Mesh-Simplification

[xuefeng7]

thanks for the information, one question is: is there anyway to keep track of which faces are merged into one face? like if you have a labeled mesh, after decimating, how could you know the label for each new face？
Thanks!

[mikedh]

@xuefeng7: I think that would be pretty easy in a native numpy implementation but might be tough with a wrapper.

I referenced and consolidated this into the enhancements list and would be as always mega- happy if someone wants to PR this 😄 . Thanks for the report!

[jonnymaserati]

I'm doing this via open3d pretty simply, I can pass on that code if it helps?

[mikedh]

Oh yeah actually the open3d implementation of this is pretty good, and they appear to be distributing through wheels now. I added a thin wrapper to open3d in 8b9daf2 that seems to work well.