How to scatter direct light through frosted glass

[sayedhusain_almousawi]

Hello community, I’ve been struggling with this issue for quite some time now and I’ve searched every corner of the internet to no avail.

In simple terms, I’m trying to create a frosted glass material to give realistic light scattering effects. I’ve tried multiple ways of creating such a material, with satisfactory results when it comes to seeing the blurred objects behind it. However, the part that I’m struggling with is that when the direct sun rays go through the frosted glass and hit a solid object, the light is as sharp as if it came through clear glass. That is obviously not realistic and not desirable.

I’ve tried several materials, from the frosted glass that comes with VRay Material Browser, to creating VRayMtl and changing refraction settings, to VRay2SidedMtl, and ending with VRayFastSSS2. All my experiments resulted in the same sharp pass-through light.

I use VRaySun with a multiplier of 1. The closest result I got was when I changed the VRaySun’s multiplier to 30 and higher, but I’d like to avoid this method because it means that all my lights and shadows will be soft.

Any ideas?

Thank you.
Ok

[sayedhusain_almousawi]

Anybody has any ideas .. ?

[fixeighted]

Turn on caustics and in the glass, untick 'affect shadows'

[sayedhusain_almousawi]

Thanks a lot! I spent days researching this, turns out the solution was this simple. You saved me more days of research. Thanks again.

[fixeighted]

No probs.
One thing I noticed is that you cannot use 'reflect on backside' with this...doesn't really matter for this case but it did stump me for a while

[sayedhusain_almousawi]

I've never found myself needing to use this option. I hope that I will never need it for a frosted glass haha.

[Joelaff]

I would definitely try to fake it with an invisible plane light on the inside (possibly texture mapped) just for the render speed improvement. But if you have the time...