Merge Normal orientation calculations with Custom Orientations, to make it work the same all accross the table:
- One or more faces: use average face normal (first edge of faces define tangent)
- One edge: use edge itself as normal (vertex normals define tangent)
- One vertex: use vertex normal (tangent is perpendicular to normal and z-axis)
- Two vertices => edge orientation
- Two vertices => face orientation
*I tested quite a bit but please report any bugs this might have caused.*
ADDED FILE WARNING: source/blender/src/transform_orientations.c