create s3dlib.yml

[fzaverl]

PR Summary

[QuLogic]

This is interesting; how do you manage to workaround Matplotlib not implementing a true 3D renderer?

[fzaverl]

Regarding your question: there are basically two aspects to creating the 3D surface visualizations.

First, the 'stacking' order of the faces in the viewing direction. Matplotlib handles this using the calculation of z-order for the Poly3DCollection using the axes view direction. However, it is limited to a single Poly3DCollection object when added to the Axes3D. This is why the S3Dlib documentation indicates that multiple surfaces may need to be added together
to form a single 'composite' surface for Matplotlib rendering. ( https://s3dlib.org/examples/composite.html )

Second, each face needs 'color modification' relative to the lighting direction. S3Dlib handles this using the object methods shade, hilite, and map_cmap_from_normals. These method are called prior to adding the object to the Axes3D for Matplotlib rendering. ( https://s3dlib.org/tutorials/render_control/visualization3d.html )
The viewing direction is only needed for these three methods for open-surfaces having front and back surface effects, or for non-orientable surfaces. ( https://s3dlib.org/guides/guides/shading_open.html )

Matplotlib still does the rendering. However, when another rendering engine is used to view the objects, the 'color modification' methods by S3Dlib should not be used. This is shown in Geometry Export examples which use Blender.
( https://s3dlib.org/examples/export.html ).