OTOY Forums

Holla,

read the manual about "Direct Light Importance" in PMC. Yet question(s) came up.

Direct Light Importance influences the sampling of Direct Light.
a. Is light refracted while travelling eg. through glass still direct light?
b. Is light reflected by glass on its surface still direct light?

optional c.: Consider an "extreme scene" where like 99% of the scene is lit by a blackbody through glass. How to set such a render up properly?

TIA
ms

Hi heretic,

c) this depends on what you need the light to do through the glass.
If it's a window or something like that, where you don't really need the light to properly be refracted through it, then you can enable "fake shadows" on the glass material.

If you need all the proper caustics of the glass, then PMC is usually the best, and use some caustic blur (too much and the caustics will not be crisp, but just a little and it will work well without too much effect on the caustics quality). The default of 0.01 is usually quite good.
If you want accurate caustics, then there is not really any trick to get them fast. They are computationally intensive and therefore will take time to clean up. With experience you can tweak things to help but this is usually very scene specific.

Thanks
Chris.

Thank you a lot.

Seems in this scene as if PT is the best shot, since at later times during render only the "problematic paths" are rendered.