ref: a8c810950efd587b9f46d6ddfa0de4930939ae9f dir: /mdl/basis.obj/
mtllib basis.mtl v 0 0 0 v 1 0 0 v 0 1 0 v 0 0 1 usemtl x l 1 2 usemtl y l 1 3 usemtl z l 1 4