Caustics indoor swimming pool

[Guest]

I am trying to simulate decent caustics in an indoor swimming pool and I cant seem to find workable settings. I can simulate caustics fine on an exterior using VRaySun. However within my interior I have lots of ceiling spot light meshes each of which have a VRay plane light underneath (about 100mm x 100mm) with the intensity set to luminous power. These lights don't provide caustics, if I increase the multiplier, the water just goes really bright.

I then tried placing a large spot light with diffuse off that sits just below the ceiling. The hotspot covers the entire pool area, not sure if this is the correct method? This produces caustics fine in the water but doesn't produce any reflective caustics. I got a few reflective caustics after I put the multiplier up to about 10-20 but this also increase the brightness of the caustics on the water.

So whats the best practice for interior? I am about to try and put spot lights under each of my ceiling lights with the diffuse off to see if it produces more reflective caustics.

I have been following this as a reference http://www.cg-blog.com/index.php/201...p-tutorial.htm. They set the water thickness to 3cm, is this correct or should the water be the full depth of the pool?

Thanks.

[Pixelcon]

Do you have the reflective caustics checkbox checked in your GI settings? It's off by default, I believe...

[deneb26]

Hi

in my projects i mostly fake caustics with a rectangular shaped target-spot with a caustic-texture as projection map.
I position it just at the pool-ground aiming upwards. gives some nice effects without the hassle of calculating real caustics.

cheers
Ale

[Guest]

Good tip deneb26 I resulted to doing that for now as I had seen it done before, but I really wanted to try and get it nailed "the correct way". I switched to using VRray IES lights under each ceiling spot to see what that does, but render times are long and it takes a lot of trial and error to see the results.

[Zdravko]

Yes, rendering caustics can be time consuming.
If you send us the scene we can have a look and probably give you some suggestions. (support@chaosgroup.com)

[Guest]

Thanks for the offer, I will compile the scene and send it over when I get a moment. Just out of interest is there any development in getting caustics to work with RT? To be able to preview would be fantastic as it is a bit hit in the dark when working out the settings.

[Zdravko]

Just out of interest is there any development in getting caustics to work with RT?

VRay RT GPU can render caustics, but it needs a lot of time to clear them out.

[AltoR]

Did you try this ? http://www.dualheights.se/caustics/
I never used this software yet but it seems quite convincing, although not physically accurate.
Here is the method I always use on still images, works very fine to me: http://vimeo.com/28008416

Cheers,

AltoR

[samuel_bubat]

You can try placing a dummy light inside the pool that refracts caustics to the ceiling.
Worked always pretty well for me (in times reactor water was still with us ).
http://sorceress.netfrag.org/optix/s_caustics_01.mov