Caustic usage

[Micha_cg]

Hallo,

today I have play a little with caustics. I wonder me, that caustics should be enable in GI mode only. From Rhinoman|AIR I know, that caustic could be used in non GI mode too. Is it an interface bug, that the caustic parameters are disabled if GI is disabled?

Regards
Micha

[joe_b]

Caustic usage

I'm glad you reminded me of this. I originally thought caustics were only around in GI modes - so the UI hides it otherwise. However, if you check caustics on then turn GI off the caustics stuff is still calculates the caustic map and whatnot. So my first gut-instinct is that I have just made a UI error in thinking that caustics aren't used in non-GI renders. I'll look further into this. Thanks

[Micha_cg]

Caustic usage

I have tested caustics: a sphere at a plane and a spot light. The progress window tell me, that a caustic map will be calculated. But I can not see a caustic effect. Maybe I have overseen something. Could somebody test it?

[flipside]

Caustic usage

works fine for me (except the fact that caustics tab is gone when not using GI).



http://www.aversis.be/vrayrhino/caustics.zip

[Micha_cg]

Caustic usage

Thank you Wouter. It works, but if I replace the point light with a spot, I get no caustics. I have inserted the spot with default settings. Any idea?

EDIT: I have set "inverse square" and intensity 1000, now I get a caustic effect, but the light is quite dark. My theory, the decay settings are not used for the caustic, it works in "inverse square" allways.
Simple test: set the point light in "linear" mode and intensity 2 - no caustics.

Conclusion: caustics dosn't work in "linear" and "inverse" decay mode. A Bug?

[joe_b]

Caustic usage

I'll ask Vlado to take a look at that issue

[vlado]

Caustic usage

Conclusion: caustics dosn't work in "linear" and "inverse" decay mode. A Bug?

Nope, this is not a bug. Inverse square decay is the physically correct one. Because of the way caustics are calculated, the inverse square decay is obtained automatically and there is no way to change this - it's an intrinsic property of photon mapping.

Best regards,
Vlado

[Micha_cg]

Caustic usage

Thank you Vlado. I have suppose so that it is so, but I have not find any info about it at the help page. MAybe you could add an info.

Regards Micha

[flipside]

Caustic usage

In my example, I used a point lights with inverse decay and a light multiplier of 1000.

If I for example use no decay, and a multiplier of 1, you see no caustics. To solve this, simply increase the global caustics multiplier to 1000 in the caustics rollout.




Works with spotlights too.

[Micha_cg]

Caustic usage

Thank you, good workaround.