noise in shadows with LWF

[plastic_]

when i use LWF (max gamma 2.2), there is visible noise in shadows, compared to using vray with color mapping to gamma 2.2.
i would like to raise the noise-in-shadows threshold but i'm not sure where it is...
what would be the best way to deal with that?

[panthon]

I found out the same using linear instead of gamma correction in Colormapping rollout. No matter what u do, u wont get rid of the noise using linear in the shadows, it's like vray decides not to sample there in that dark corner and therefore noise pops up.

[plastic_]

yeah, which sounds logical. but there should be a way to tell vray that it should shift the shadow-threshold for calculations?
i can't believe it isn't possible, with all the obscure noise settings in the render dialog?

[studioDIM]

Lowering the rQMC noise threshold (or if GI is fine, just the AA threshold)helps.
Just make sure your max subdivs (QMC AA) value isn't too high, as lowering the noise threshold will ensure you're very likely to hit it everywhere else as well.

Lele

[plastic_]

man this QMC stuff...
i'll be damned if i ever get it.

[studioDIM]

There's a good chance also the adaptive amount has to be set to < 0.5.
If QMC gi is set as primary, that too has to be raised fairly high.

A very clean setup here is as follows:
QMC AA 1-12 / use rQMC thresh
no image filter
QMC GI 32-48 subdivs
LC whatever setting is preferred (low is fine)
Adaptive amount : 0.45
Noise threshold : 0.002

This cleans scenes at the expense of rendertime, but noise isn't visible in the darkest of places even at 400% zoom.

Lele

[vlado]

yeah, which sounds logical. but there should be a way to tell vray that it should shift the shadow-threshold for calculations?
i can't believe it isn't possible, with all the obscure noise settings in the render dialog?

In newer versions, you can tell V-Ray to use color mapping only internally to guide the number of samples, but to produce a linear color image in the end. So, for example, you set the color mapping gamma to 2.2 and V-Ray will calculate as though gamma 2.2 is applied to the result, but without actually applying it. To a very large extent this solves the whole issue.

Best regards,
Vlado

[studioDIM]

Aaaaah, lovely to hear...

Lele

[Sushidelic]

yeah, which sounds logical. but there should be a way to tell vray that it should shift the shadow-threshold for calculations?
i can't believe it isn't possible, with all the obscure noise settings in the render dialog?

In newer versions, you can tell V-Ray to use color mapping only internally to guide the number of samples, but to produce a linear color image in the end. So, for example, you set the color mapping gamma to 2.2 and V-Ray will calculate as though gamma 2.2 is applied to the result, but without actually applying it. To a very large extent this solves the whole issue.

Best regards,
Vlado

Yeah, this was a point on the changelog that made me smile! Cool implementation!