Computes smooth, area-weighted per-vertex normals.
Vertex positions. Length must be a multiple of 3.
Triangle indices. Length must be a multiple of 3.
Normals with the same length as positions. Vertices not used by any triangle get [0, 0, 0].
positions
[0, 0, 0]
If a length is not a multiple of 3 or an index is out of range.
Computes smooth, area-weighted per-vertex normals.