ref: 1e2596cb1497bd8e491a3b9cd05062a98256ab5d 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