Hi Larry,
I smashed/broke my finger today, and woke up in the middel of the night, so while waiting for the vicadin to kick in so I can return to sleep I thought I'd mess with caustics some. Here's a glass with surface and volume caustics. The light pattern on the tabletop/floor/whatever is caused by surface caustics. The light source is slightly behind the glass and from the left side in relation to camera POV.
One thing I forgot to mention earlier that you all probably know is that in order to use caustics, you need a volumetric light source.
Mark Simpson
