Cloudy plastic cycles

[eobet]

I was just on a hunt for this, and there seems to be an artifact to this way of doing things that I’m fairly sure doesn’t appear in reality (someone at work is actually going to test this tomorrow):

Note the internal reflection in the screenshot above

For a more correct result, I used the node setup I found here (but granted, this is much more difficult to understand, and I currently haven’t everything figured out):

Trying to achieve semi-transparent plastic with blurry refraction

One thing to note is that when using caustics for light transport, you may want to help it out unless you can afford really long render times as many samples will be required to get it up to about correct brightness. Helping out means adding to whatever caustics is doing, so use with care as this is not energy conserving as far as shadows are concerned. My initial general approach to such materials, is to start out with something like shown below. Since your model is properly double walled with…

Note the lack of internal reflection in the screenshot above

(Btw, what I’m trying to simulate is shining a light through a semi-translucent plastic.)