Cuastic render error?

[RevitGary]

Max 2009. I applied caustics to my pool water in object properties. When I hit render I get the error message " there are no caustic generators in the scene" I have caustics turned on in the indirect illumination dialog box. Whats going on ?

[mattclinch]

none of your lights are emitting photons? what lights are you using?

[RevitGary]

daylight system.... mr sun and mr sky

[luckymutt]

Select the Daylight, right click->properties, mental ray tab, and check "Generate Caustics"

If you want *only* the Sun and not the Sky to produce Caustic photons, the select the Daylight, on the menu bar, go to Group->Assembly->Open

Then you can select the Sun and Sky seperately to apply different object properties to, such as generating caustics.

[SandmanNinja]

Generating caustics everywhere can slow render time down.

If the object that you want to have caustics is a small part of the total screen space, make a spot or direct light that only generates caustics and narrow the beam to just enclose the object wanting caustics.

[luckymutt]

^^-Excellent point

Definately the best way to go for hero objects(though make sure the light is only set to affect the hero object).

 

In the same spirit, I'd like to append my previous post by saying that if in the OP's scene the pool takes up a broader amount of the final image, using the Photon Target in the mrSun may help (provided that you are not using GI photons for the entire scene and you only need the photons for caustics - just focus it to encompass the water. You may get wonky results if you need the photons for GI in a broad shot with the focus in one area)

 

Another thought: if you are only trying to create refractive caustic effects on the pool's shell, faking it with the material could be much quicker.

Edited February 27, 2009 by luckymutt
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