How to get the scene loader to generate tangent space for a loadable model?

[Vladimir Sazonov]

How to get the scene loader to generate tangent space for a loadable model? It seems he does not do this automatically. Because materials with normal map are rendered incorrectly. Instead of a relief, a black surface is obtained. I tried load .obj model with map_Kn or map_Bump field in .mtl file. But it does not working.