In case it helps, typical debugging procedure:
- hypothesize causes
- perform tests to rule out (or definitely rule in) causes.
For example:
- “Maybe this is tangents”
- Well, tangents are only used by materials with normal maps or parallax maps. Ergo: give them a material without a normal map and without a parallax map and see if the problem stays or goes away.
P.S.: Tangent buffers are like normal buffers… they are mesh specific. You only have to generate them once for a particular mesh. To see if a mesh has a tangent buffer, call getBuffer(Type.Tangent) and see if it returns a buffer with data in it.