caustics & shadow question

[noam_farhi]

hi evryone.
i just started playing around with caustics a little bit. i followed the tutorial i found in the forum, which was very helpfull.
before trying the caustics on the scene, i had vray shadows on (area shadows) with "effect shadows" on - which gave me a nice transperant shadow. after turning caustics - i got a nice caustic effect, but the shadow became flat and dark, as if effect shadows was off. any ideas / tips?

another little one: sometimes, at second render of the scene, the caustics change. i thought maybe the map is saved and effect the result (something like "incremental add to current map" in IR), but that mode is off in the caustics parameters. any ideas about that?
thanx a lot

[losbellos]

I also played with caustics,
shadows are much darker when caustics on.
Dont know why.

[Dusan_Pavlicek]

A long time ago I asked Vlado about it and he told me that the "Affect Shadows" parameter is ignored (turned off implicitly) whenever caustics is used. The motivation is that it is the caustics that is used to calculate the physically correct effect and therefore using "Affect Shadows" (being fake and artificial) don't make sense in such situation.

[noam_farhi]

thanks dusan - that explains a lot. it's exactly as you described it.
i guess i just didn't play with it enough - but for now it seems that the caustic effect could look better with the "effect shadows", despite the logic you mentioned.
anyway, any idea about why on second render the caustics become different (more grainy, and with splotches)?