In reality, a total black shadow is created, and the light refracts, because the bottle act as a lens. The only thing you see are the caustics.
Well, now I'm talking in 3DS terms, but still, they are quite close to reality. We have a crystal candle holder, and it 'creates' a dark grey shadow, with some light spots in and outside the shadow. Maybe I don't explain it well, but I hope it's a bit clear
EDIT
@ShDwBoRn, GMAX is free, does look much like 3DS. Google Sketch Up, free as well... Blender, believe that's free too...
This post has been edited by Roani52: Jun 3 2008, 06:54 PM