This is the right mapping  \
position(x,y,z) -> (-x,-y,-z)  && normal(x,y,z) -> (-x,-y,-z)  && uv(u,v) -> (u,1.0-v) && \
faces[i] (v0,v1,v2) -> faces[i] (v0,v2,v1) (mapping cull direction)