Glass and liquid

[Mnietek]

I try to model a glass with liquid inside. Both glass and liquid is colored by fog.
I try to do this in 2 ways.

First I model two objects: glass and liquid slightly overlapping each other. But it's look no good. Rendering and computing caustics takes too much time.

Second - I model three surfaces (see picture). I make three materials and assign them to this surfaces. When glass and liquid have no fog it's no problem. But how can I define fog color for
glass-liquid surface? For this surface fog color and density is different on other sides. When I set up two sided material for this surface fog is visibile only for facing material. WHY?

pls help...

thanks Mnietek

[Zandar]

Hmmm. In this illustration, it appears you have the liquid right up to the edge of the inside part of the glass. In the second, you have it moved in between the inside and outside portions. There's a trick to getting the right refraction, and that's by removing the polys of the glass where the water or liquid is, and expanding the liquid to the outside edges of the existing glass. For a better explanation of what I mean, do a search for glass and liquids and you should turn up some good threads on the subject. Hope that helps.