I’m also having difficulty with fbx files, but I have no idea of their origin, as I’m porting. KakCat’s data dumper has identified for me that one particular model has no meshes (whereas if I use the official ASSIMP Viewer it thinks it has two, and some other viewers see it as one).
It’s useful information, in that it gives me somewhere to look, but it shows that parsing with ASSIMP and AssimpNET isn’t yielding the same results. Worrisome.