Noise flickering

[Dalton Watts]

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! :)

[romullus]

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.

[Dalton Watts]

Thank you romullus but it is on by default :)

[Ludvik Koutny]

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.

[Dalton Watts]

Thank you Ludvík! Will try it and update the thread with the new animation when i can.

[Ludvik Koutny]

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.

[Dalton Watts]

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.

[Dalton Watts]

Ok, i'll probably be better off animating DOF in post.

[Ondra]

interesting... can I get the scene? I would love to look at what exactly is causing it

[Dalton Watts]

Sure thing Ondra! Just give me a few more days to send it to you since i've been quite busy lately.

[Eszter Kallai]

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

[Dalton Watts]

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.

[maru]

Just a random guess, but flickering even when using PT+PT is typical for scenes where Vray HDRI was used as environment lighting.

[tolgahan]

I think main problem is precompution hdc file.

[Eszter Kallai]

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