Excuse me! I had assumed that you did not used the obj impotador. But I tested the skin that you converted. The weights of most vertices is well settled . Only the weights of the head are a little unbalanced. I believe that the vertices of the nose to the chin region were not assigned weights 1 on the strength of the head, if you converted using the modifier skin, or have not been assigned 100 weight on the strength of the head, if you used the physique. So part of the mouth folds into the neck. I also realized that the file is too big. He has more than 12 Mb. This is because of the format of the texture file. Use texture files in DDS format and RGB colors reversed. Their models will be reduced. In my testing with AL realized he did not generate any incompatibility in my game. There was no shading or excessive illumination. His model is cool. Congratulations!