Fake frosted glass material

[stevesideas]

Is there a way to do this without having all the physical accuracy and therefore large render times?

[theedge]

Maybe small scale noise map in bump could do the trick ?

[jhall.nz]

If it's in the background and not a major feature you could try this post solution.

Render the glass objects with a normal everyday refractive glass material to get the quick and clean render times. In post use a mask (object/material ID, wire color) to blur the glass objects, overlay some diffuse color usually white/blue, and finally add/screen the reflection/specular pass back on top.

[theedge]

Here are two tests I made with two very different methods :
- First one with the process described in my previous post : basic glass with just a small scale noise in the bump slot.
- Second one : 100% fake : I used Ky_Surface Blur plugin. It's a render effect that... blurs a surface (by object and/or material ID)

The second version renders almost twice faster. But it comes with tradeoffs of course. You see that whatever the distance of objects behind the frosted glass, they recieve the same amount of blur. While in the first version, the closest ones are less blurry.

https://vimeo.com/395998343
https://vimeo.com/395884855