[Peder]

One of the more difficult things to achieve for me is backlit glass. What would be the best way to have a lightsource inside a building light up frosted windows as seen from the outside. SSS or roughness?
Any pointers appreciated.

Peder

[pwrdesign]

I'ld say it depends on how your scene looks.
I've you got a few windows that you want to have backlit, there shouldnt be a problem, if you got a whole building, it might be though on the rendertime.

Anyway I would start to test with SSS.

Another way would probably be to do it in photoshop..

http://www.grafica3dblog.it/photoshop_t ... _glass.htm

[deflix]

or save a grad image like enclosed as an MXi in MXrender and use as an emitter applied to a plane behine a sheet of glass (frosted) hidden from gi.