Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Dalton Watts on 2016-12-27, 16:18:36

Title: Noise flickering
Post by: Dalton Watts on 2016-12-27, 16:18:36
Hello,

I'm using PT+UHD in a few dollie animations but i'm getting noise flickering no matter if i save uhd cache in 30 frames interval and loading them from file.

In the example in attachment (90frames) i'm only using 40 passes (full denoise amount 0,6), maybe i should raise the passes so the noise isn't perceptible? It was done using "load from file". The .uhd file was saved using only the 1st frame of the animation. But if i use the middle frame the result is the same.

Thank you! :)
Title: Re: Noise flickering
Post by: romullus on 2016-12-27, 16:48:53
That doesn't look like UHD flickering, that's more like undersampled noise "boiling". You can try to make it less visible by locking sampling pattern in render setup>performance>performance settings. Check that box on and see if noise perception is better. It shouldn't boil anymore, but rather stay in place.
Title: Re: Noise flickering
Post by: Dalton Watts on 2016-12-27, 17:18:31
Thank you romullus but it is on by default :)
Title: Re: Noise flickering
Post by: Ludvik Koutny on 2016-12-27, 19:11:49
AFAIK this is some sort of "optimization" that's supposed to make DOF rendering faster. You can sort of see it especially in first few passes, where you see DoF highlights being kind of diagonally stretched.

So far there is no workaround, you just need to render DoF clean in order to get rid of this flicker, so decreasing GI/AA would be your best chance.
Title: Re: Noise flickering
Post by: Dalton Watts on 2016-12-27, 19:37:20
Thank you LudvĂ­k! Will try it and update the thread with the new animation when i can.
Title: Re: Noise flickering
Post by: Ludvik Koutny on 2016-12-28, 19:00:12
It actually seems this problem has been made a lot worse with adaptivity. I have some scenes where adaptivity stops refining those flickering diagonal streaks after first few passes.
Title: Re: Noise flickering
Post by: Dalton Watts on 2016-12-28, 20:56:57
I also realize that, if i use "load from file" and point to an .uhd file generated from any frame of the animation, and then compare any frame with a frame using "calculate from scratch", the latter has much less noise.
Title: Re: Noise flickering
Post by: Dalton Watts on 2016-12-29, 15:45:26
Ok, i'll probably be better off animating DOF in post.
Title: Re: Noise flickering
Post by: Ondra on 2016-12-29, 22:16:57
interesting... can I get the scene? I would love to look at what exactly is causing it
Title: Re: Noise flickering
Post by: Dalton Watts on 2016-12-30, 18:49:28
Sure thing Ondra! Just give me a few more days to send it to you since i've been quite busy lately.
Title: Re: Noise flickering
Post by: Eszter Kallai on 2017-02-20, 11:58:50
Hello,

I'm using PT+UHD in a few dollie animations but i'm getting noise flickering no matter if i save uhd cache in 30 frames interval and loading them from file.

In the example in attachment (90frames) i'm only using 40 passes (full denoise amount 0,6), maybe i should raise the passes so the noise isn't perceptible? It was done using "load from file". The .uhd file was saved using only the 1st frame of the animation. But if i use the middle frame the result is the same.

Thank you! :)

Hey,

has this been solved for you in the meantime?

I'm experiencing the same problem when I use PT+PT for animation.
It was other type of GI flickering when I rendered the same scene with PT+UHD
Title: Re: Noise flickering
Post by: Dalton Watts on 2017-02-20, 17:20:15
I haven't tried rendering this scene but i tried other scenes and haven't had any noise flickering problem. Probably i missed something in my workflow back then. I always precalculate cache prior to rendering and i haven't noticed any noise flickering.

I'll try this scene again with the new workflow and see if it solves it.
Title: Re: Noise flickering
Post by: maru on 2017-02-21, 19:00:26
Just a random guess, but flickering even when using PT+PT is typical for scenes where Vray HDRI was used as environment lighting.
Title: Re: Noise flickering
Post by: tolgahan on 2017-02-21, 19:22:19
I think main problem is precompution hdc file.

Title: Re: Noise flickering
Post by: Eszter Kallai on 2017-02-26, 21:44:33
Here are some tests with PT+ PT
I think the reason for the flickering is that I rendered only 2-3 passes to keep the render time low and my frames were still noisy. Despite I used the full denoise, I got the noise flickering effect.

Here is what I got with Pass limit 2

Here is what I got with Noise level limit 6
Title: Re: Noise flickering
Post by: Ludvik Koutny on 2017-02-27, 10:08:13
2-3 passes are way too low to get any meaningful result. You may want to decrease GI/AA balance to something like 4-6 to get more AA rays (passes) within similar rendertime.
Title: Re: Noise flickering
Post by: Eszter Kallai on 2017-02-27, 11:44:18
2-3 passes are way too low to get any meaningful result. You may want to decrease GI/AA balance to something like 4-6 to get more AA rays (passes) within similar rendertime.
Thanks! I'll try it out!