MAXON CINEMA 4D: Cinema 4D Forum Adobe After Effects Forum

Splotchy IR GI in low light

COW Forums : Maxon Cinema 4D

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Jareb CoupeSplotchy IR GI in low light
by on May 4, 2015 at 3:48:45 am
Last Edited By Jareb Coupe on May 10, 2015 at 12:25:00 pm

Usually, if I have an issue with IR Cache, I just switch over to QMC. This particular scene, however, I'm experiencing a different issue with each GI method.

With IR Cache, I get really splotchy areas in low light regions of an interior. Even when I crank the samples/accuracy way up.

That wall mat is just flat white. Looks burned all over and snotty around edges - reminiscent of a JPG at 0% quality. How can I get the shading more uniform? I have the settings cranked already!

I was using QMC earlier in the scene, which didn't have the issue - but it suffers from something else. Some cracks/crevices seem to pick up some GI from somewhere, even though opaque objects are obstructing the way. It creates an unrealistic/buggy glow in these cracks. I get the sense that this is a pretty typical bug in QMC.

Has anyone experienced either of these issues? I'm open to suggestions!

Here's a shot of the GI settings. If I bump the light up a little, the artifacts lessen. But I can't light this area, it needs to be realistic & dark.

Return to posts index

Brian JonesRe: Splotchy IR GI in low light
by on May 4, 2015 at 9:06:39 pm

the Help on Global Illumination has a lot of good info. I'd start looking in there as the Samples/Accuray in the general tab can't do everything, I think you'll have to dig into the Irradiance Cache tab of the GI settings (and whatever you are using for your Secondary, if you are) - first guess is that Record Density there would have to go up, either as a preset value or open it up and tweak due to what your scene contains. That's just a guess though.

Return to posts index

Jareb CoupeRe: Splotchy IR GI in low light
by on May 9, 2015 at 5:41:36 pm

I've scoured the Help, reviewed all settings, and watched a few vids. But have been unable to get rid of this issue in my scene (lit by IR). The record density in the example above was already using the High preset. I also didn't realize until recently that it's not just low light renders - it also affects medium light areas. It's just blotchy/burned all over.

It's quite a dilemma - I do like QMC as an alternative to IR, but then I get the weird random light/leaking. I'll post a pic of that as well, if this thread picks up.

Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 All Rights Reserved