ref: 9a4039805fa1d7a99929e7254a6bde3fb8e1dc2e dir: /mdl/tribasis.obj/
mtllib basis.mtl v 0 0 0 v 1 0 0 v 0 1 0 v 0 0 1 usemtl x f 1 2 3 usemtl y f 1 3 4 usemtl z f 1 4 2