Mental Ray Caustics

[cgbeige]

is that your total photon count or per light? Caustics are slow and that's a shitload of caustic photons.

[photograph3d]

That's my total photon count. I had upwards of almost 2 mil and brought it back down so i could see how this particular scene would look with caustics. So would you recommend even cutting the photons back even more?

[cgbeige]

well it's always a balance between quality and speed so start with 50,000 and go up if it's not good enough. Also, check that you're not tracing more than you need to. 5 refractions max for raytracing and FG should be good.

[photograph3d]

Yeah I do know that I am tracing a few at 15. Most are set to 5 though. The trace is in Render Settings isn't it? Thanks for the thoughts. Do you find caustics helpful in Architecture? I haven't used it much.

[cgbeige]

reflections can be that high but refractions at 15 is going to be retardedly slow and not really beneficial visually unless you're making a museum of aquariums :p

Don't use caustics unless you have too (only for light refraction in water, glass, etc) where the light passes through something transparent. The number value is the amount of times the light ray can pass through different transparent objects so if you have no transparentl objects, turn it off. That's definitely what's killing your render speed

[photograph3d]

Yeah, I have a few wine glasses with various amounts of wine in each and then 1 champagne glass, so I was really interested in the difference in the render using caustics.

Ironically, it cruised through the first 60% of the Photon Emission, in 15 minutes. It's been the last 2 days, that it has been dragging. It seems, the closer it gets to finishing that part, the slower it goes :banghead:

I really appreciate your 2 cents worth more :thumbsup:

[Galakgorr]

limit your caustic photon emission to areas that actually need caustics, rather than just spraying caustic photons everywhere in the shot. try removing caustics from your existing lights, and then create a spot light which casts no real light but only photons for caustics. frame the light so it's only covering areas which need to receive caustic illumination. this way you can get cleaner results with way less photons than you would otherwise need.

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