Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: lupaz on 2019-01-11, 16:20:17

Title: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: lupaz on 2019-01-11, 16:20:17
Hi there,

I feel that the color bleeding is too strong in general. How can I reduce it globally and not with rayswitch?

Thanks.
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: sprayer on 2019-01-11, 16:30:19
I was have similar task in some product render and find what you may reduce it with light, make light less strong but with more area light just experiments and you will see how it will be less visible bounce color. Would help to use light from HDR Light Studio
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: lupaz on 2019-01-11, 17:56:00
Thanks, but I was hoping to control it globally by reducing the intensity of the secondary GI.
Is this possible to do?
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: Ondra on 2019-01-12, 00:16:33
Only solution now would be to render in elements and darken the CESSENTIAL_INDIRECT pass in post...
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: maru on 2019-01-14, 11:25:46
Or you can reduce Max Sample Intensity in the Performance tab to lower the overall GI intensity (it's not really bleeding color, but more like brightness).
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: lupaz on 2019-01-14, 16:03:47
Thanks Maru, Ondra.

I like the contrast when I lower the MSI value.
But it does something strange with 1 or lower values though:
All textures in reflections are blurred to their average color.
For example if I have the camera pointing to a mirror, and I have MSI in 0.1, all textures reflected in the mirror are blurred to an average (or clamped?).
The same textures visible outside the mirror remain ok.

I read this https://coronarenderer.freshdesk.com/support/solutions/articles/5000515636-what-is-max-sample-intensity-msi- (https://coronarenderer.freshdesk.com/support/solutions/articles/5000515636-what-is-max-sample-intensity-msi-)
but it doesn't seem to say anything about that; only about reflection caustics. No?

Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: maru on 2019-01-18, 13:12:12
For example if I have the camera pointing to a mirror, and I have MSI in 0.1, all textures reflected in the mirror are blurred to an average (or clamped?).
The same textures visible outside the mirror remain ok.
Strange. Can you post an example of this?
I guess it's because reflections are basically GI, so they get clamped by MSI too.
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: lupaz on 2019-01-18, 16:38:26
Sure.
Here you go.

Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: TomG on 2019-01-18, 16:51:59
Probably a strong argument for not using such a low value of MSI (which is not recommended - the default should be fine in most cases).
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: lupaz on 2019-01-18, 18:05:22
Ok. Thank you.
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: maru on 2019-01-23, 11:14:17
Yeah, that's clamping. Definitely expected.
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: lupaz on 2020-02-19, 17:16:08
Yeah, that's clamping. Definitely expected.

Hi.
Any chance to have  in a future version Max Sample Intensity lower than one without clamping?
I feel that by lowering that value I get more realistic results.

Thanks.
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: maru on 2020-02-19, 17:35:15
Yeah, that's clamping. Definitely expected.

Hi.
Any chance to have  in a future version Max Sample Intensity lower than one without clamping?
I feel that by lowering that value I get more realistic results.

Thanks.

What you are saying is extremely unexpected. Can you please share some example images?
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: lupaz on 2020-02-19, 22:11:13
Hi Maru.
A while back I posted some images. You'd need to scroll up in this same thread.
I believe the clamping is only in reflections.
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: maru on 2020-05-11, 17:16:45
In reality there is no GI clamping = realistic.
In Corona there is small GI clamping by default = less realistic, but acceptable
Setting heavy GI clamping makes GI darker = unrealistic.

I do not see how using heavy GI clamping can make the image more realistic. If you are expecting darker shadows, lower the materials' albedo instead.
Title: Re: How do I reduce the strength of secondary bounces (color bleed) globally?
Post by: lupaz on 2020-05-11, 20:49:40
Understood.
No worries.
Thanks Maru.