Im currently working on some car headlight elements. I am having problems getting good results with the indicator section. The main section is looking ok, but the reflector in the indicator wont show through the details at all, and turns red.
the fog depends alot on your mesh, so for instance if the back of your mesh on the right is open but the mesh that is red has a closed back then the fog would be hugely different.
I think for what you want.. fog is not ideal. As your glass would always be the same color no matter what the thickness is. Which is the opposite of how fog works.
da force is on it. basically fog is great for objects that would normally be transparent in thin amounts but the light gets tinted the more of the substance you look through. with plastic like that the plastic itself is tinted. so a tinted refraction is usually better than using fog. i would actually turn off the fog all together and just use refraction color