I am the developer of the DirectX .x exporter addon for Blender, and recently I've encountered an issue that I do not understand. On a simple skinned mesh in a .x file, when using more than one material index in the MeshMaterialList template, the mesh becomes deformed in a very weird way.
The mesh is simply a rhombus composed of two triangles stacked vertically, and contains two bones that each fully influence a tip and share 50% of the influence on the vertices in the middle. When using only one material in MeshMaterialList, or foregoing the MeshMaterialList template entirely, the mesh deforms correctly. When instructing the bottom triangle to use a different material than the top, the weird deformation occurs.
I've attached two versions of the .x file: one with only one material, and the other with two. I test the files I export against the DirectX Viewer.
Can anyone tell if these files are malformed in some way? I don't really understand this problem.
Thanks for any insight!