Reflective GI caustics - when to use?

[tricky]

I am rendering a bathroom - lots of reflective surfaces - mirrors - spot lights - marble etc.

Should I be ticking on reflective gi caustics? I've never really played around with this before. All I know is whenever I have tried to use 'proper' caustics, it turns into a scary nightmare.

How do the two types of caustics relate to eachother and why is reflective GI caustics disabled by default?

[vlado]

In V-Ray 3.0, you can actually enable reflective GI caustics in conjunction with the "max. ray intensity" option - the latter will help to keep the noise and render times under control.

Reflective GI caustics are disabled by default, because they are typically a major source of noise, especially in the situation that you describe. In the 2.x builds, we don't have the "Max. ray intensity" so cleaning up the resulting noise may take a really long time. For the 3.0 builds, the said option makes things somewhat better.

Best regards,
Vlado

[tricky]

Thanks Vlado. I clearly need to find some time to have a play around with Vray3.