[metheny1001]

Is possible to create a material that let the light pass trough (100% transparent) but only in one way (by other side is like a diffuse material)?

Imagine a cube with this material, the sunlight can illuminate inside the box, but if you put a camera inside it, it probably looks like an illuminated room.

What do you think?

[Tea_Bag]

This might not be exactly what you want but its a start

http://mxmgallery.maxwellrender.com/sea ... rch=mirror