SSS flickering

[Mr.Schorsch]

Hi Guys

I have a Problem with flickering sss mat in Animation. UHD Cache is set up to aniamtion flicker free. I use the 1.4 corona build with denoise. The gif is created with the  translucency pass.
I give the Image 10 passes to render and then the denoise is doing it's Magic to the Image. (awesome btw)

is 10 passes not enough for accurate sss calculation?
Is sss all in all hard to animate?
Am i doing something wrong?

Please help me. Would be a shame to get rid of this cool sss look in my Animation.

regards!

[FrostKiwi]

Set secondary GI to path tracing and disable denoise.
Rerender. If flicker persists it's a setup problem, and we will dig into the details, if it goes away it's a bug and should be reported.

[maru]

Yep, I would say either:
1. Test with no denoising, but with UHD - if it flickers, go to 2, else - it's denoising problem (probably due to insufficient passes)
2. Test with no denoising and no UHD - if it flickers - may be a bug, else - it was an UHD problem (which should be reported too)

Increasing GIvsAA without increasing the number of passes might also help.
And I'm curious if you really need a material setup like this - you have diffuse color, translucency, and glossy refraction. Also, the color values are very bright. What kind of material is this supposed to be?

[Mr.Schorsch]

Thanks for the fast reply. Great customerservice as usual!

The material is a plastic with very high sss. It is Close to wax in ist appearance. hard to describe. But what you see is realy close to the original.

I did some tests according to your advices. I found out, that it might be the denoising. With path tracing and uhd cache and NO denoise it seems to be flicker free.
10 passes seems to be absolotely enough for the rest of the Image (it is all brushed metal, water, and White tiles).

Unfortunately now it Looks like i need to let the sss go.
Rendering the Animation without denoise all in all would cost to much time to come to a grain free result. Increase the amount of passes would also just help the sss without giving the rest big benefits in Quality.

or is there a way to let corona safe the result before and after denoising as several renderelements. This would be awesome. Because i could keep everything as it is. Than mask the flickering denoise sss use de noisy one instead an denoise this one in AE with neat Video. this could work.... a bit of fiddeling ... but maybe an way.

Maybe i need to find a way to achieve a fake sss look using corona ao with inverted normals on my White plastic.

[maru]

Actually using just translucency with a very high value sometimes produces nice sss-looking results.

[Mr.Schorsch]

I will try that.

 Maybe you have not read my last post's edit. Is there a way to save both Images after render? Before and after denoising.

[maru]

That should be possible by adding a CShading_Components with all checkboxes checked.

[Mr.Schorsch]

What should i say... you guys are the best!! Thanks for your help.

[sevecek]

Maybe you have not read my last post's edit. Is there a way to save both Images after render? Before and after denoising.

hi,
in the newest daily build there is a dedicated "Beauty" render element that won't get denoised, so you can save both noisy and denoised image.

[Ondra]

Maybe you have not read my last post's edit. Is there a way to save both Images after render? Before and after denoising.

hi,
in the newest daily build there is a dedicated "Beauty" render element that won't get denoised, so you can save both noisy and denoised image.

actually it has separate denoising controls, so you can save it both denoised, non-denoised, and everything inbetween

[FrostKiwi]

actually it has separate denoising controls, so you can save it both denoised, non-denoised, and everything inbetween

[Off topic]
Just out of curiosity:
On what algorithm is the denoiser based?
 Is there any paper I can peek into, like the one on Random parameter filtering by advanced graphics lab or robust denoising using feature and color information by disney?
[/Off Topic]

[Ondra]

random parameter filtering is unusable in any production work AFAIK. We are using come home-brew solution mixed from multiple papers AFAIK, hacked together so it works.

[selant]

Denoising reminds me one of my favorite plugins "neat image" in PS, but it always needs the plain and at least 128x128pc area to analyse.. Of course it was a pain in complex scenes without plain area  now corona takeovers for me.

[Mr.Schorsch]

Hi... Little edit on my Problem.

I must admit that all in all i set up a  sss material where a absorbtion with translucency would have been enough. I Keep you updated how the results of the new material worked out in the Animation.

The tutorials on yout Youtube channel are awesome and help a lot to dig deeper in shader builds. Thanks again.