Hi,
I tried this initially but I only got reflective caustics (water object does have all channels in refraction as suggested in other threads). As I always fail with caustics, I wanted to just project a BW texture of refracted sunlight through waves so I put the texture in my plane light but all I get is uniform light surfaces. I tried all the texture mappings, environ, texture, real world scale, etc. Not sure how to map this light.
Personally I think caustics are the hardest part of Vray, followed by SSS. That being said, you need to turn off ‘affect shadows’ on your materials for caustics to work on them.
I use a standard old 3dsmax spotlight placed above the pool, set to only exclude/include relevant pool walls/base and using rectangular light cone. With a projector map using a nice caustic texture. The nice thing is you can adjust the cone and visually get to where you need to very quickly.
Of course this works best on a rectangular pool…
Oh, thanks guys! Didn’t know I have to turn off affect shadows. Also I kept away from 3dsmax lights 
will try them too if caustics won’t work or if it’ll take too long.
Yaaay! I finally have my caustics!!!
thx!!!
Huh? Is that a bug or do I misunderstand you? AFAIK “affect shadows” only does things when there are refractive surfaces, and if you have it enabled, it is realistic, if you have it disabled its just wrong. Why would I need to turn it OFF for caustics to work? ANd if you talk about the rest of the materials (pool floor for example) why does it do anything anyways when it’s not refractive at all?
Yes, he meant turn off shadows for the water object. Otherwise - I guess - it bypasses it.
AFAIK “affect shadows” only does things when there are refractive surfaces, and if you have it enabled, it is realistic, if you have it disabled its just wrong.
Actually it is kind of the other way around. More realistic it will be to have caustics which will generate the shadows and the light concentration effect, but they are very heavy to calculate. Therefore we have Affect shadows option witch imitates this effects by generating shadows through refractive objects and it is much more render time efficient. So you need to disable “affect shadows” option when you render caustics and enable it when yo don’t want to render caustics.
I always wondered why on earth such a thing was required!
The more you know!
Wow that was very informative and kind of logical if you think about it that way. Thanks!