Help : Best way to compute normals

wolph / numpy-stl

Simple library to make working with STL files (and 3D objects in general) fast and easy.

http://numpy-stl.readthedocs.org/

BSD 3-Clause "New" or "Revised" License

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Closed Optimox closed 3 years ago

Optimox commented 3 years ago

Hi, thanks for the library!

I'm trying to construct an stl file from a list of vertices and faces.

The example given in the doc seems ok but:

after iterating on all triangles, my_mesh.data only contains [0, 0, 0] for the normals. Should I compute them myself manually and do my_mesh.normals = my_computed_normals or is there a generic way to compute normal based on the corresponding triangle?

Thank you!

wolph commented 3 years ago

You can make the mesh recalculate them using mesh.update_normals()

Additionally, all load/open methods support a flag for that as well: https://numpy-stl.readthedocs.io/en/latest/stl.html#stl.Mesh

Optimox commented 3 years ago

Yes thank you, I computed the normals by hand but flags are useful.

Cheers Seb