Jun 20, 2014
Q: What is backfacing?
A: All planes are one sided. Compare this to a piece of paper that looks like it could be 'one sided'. This paper is in fact two sided because you can see the light reflect off of both sides.
The mesh in the 3D view can be seen similar to a two way mirror, like in those detective shows. One side of the mesh reflects the light (which is caught by the renderer) and the other side lets light pass right through so you can see through the other side.