I'm trying to create a frosted glass. Glass no problem, but how I can created frosted?
In my experience, frosted glass is one of the most difficult materials to create. There are some examples in the material gallery though.
Basically, you want glossy refraction. But you will probably also want some kind of diffuse component too - so you might end up actually using a BAM. Maybe we should have a frosted glass contest...
You can create a fairly good frosted glass by starting with the standard glass and enabling both Glossy Reflections and Glossy Refractions. This image was created with Glossy Reflections at 80% and Glossy Refractions at 97% both with a Sample Rate of 8.
One problem with this method is it causes materials behind the glass to glow somewhat. This is especially noticeable on spherical objects as shown by the obvious flare on the red ball in the left hand image. I fixed this by making adjustments in Basic Surface Parameters on the individual objects. In the case of the red ball, I turned the Diffusion down to 0.2 and then compensated for the resulting darkness by increasing The Extra Light to 89 Grey.