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#1 2016-09-12 13:56:10

InvictuS
New member

Noise on char with fur (Yeti)

Hi,

We're currently working on a project that involves working with fur. We've been getting a fair bit of noise on the character (on the environment as well but significantly lesser than the char). We've tried pumping up the sampling to as high as 32 samples x 8 Direct & 8 Indirect sampling with 6 Pixel height & width. So that gives us a total of 256 samples. Doesn't seem like much but our render time has shot up to ~6 to 8 hrs a frame and we're still getting noise, especially on the character.

Any suggestions?

Regards


Aditya Mahapatra

Senior Lighting Artist | Prime Focus World

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#2 2016-09-12 14:57:17

hulud
Guerilla dev, the guy to hug

Re: Noise on char with fur (Yeti)

Hi Invictus,

The noise can come from different reason, I have to check with you what is the source of the noise. I send you a private message.


Cyril 'Hulud' Corvazier
Guerilla developer
http://www.mercs-eng.com

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#3 2016-09-12 14:58:45

InvictuS
New member

Re: Noise on char with fur (Yeti)

Great, let me know what you need smile

Thanks


Aditya Mahapatra

Senior Lighting Artist | Prime Focus World

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#4 2016-09-12 15:20:48

hulud
Guerilla dev, the guy to hug

Re: Noise on char with fur (Yeti)

I sent you an email.


Cyril 'Hulud' Corvazier
Guerilla developer
http://www.mercs-eng.com

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#5 2016-09-12 16:05:44

InvictuS
New member

Re: Noise on char with fur (Yeti)

Hi Cyril,

I've replied to your mail from my official mail address.


Aditya Mahapatra

Senior Lighting Artist | Prime Focus World

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#6 2017-03-07 20:26:52

bonovasitch
Member

Re: Noise on char with fur (Yeti)

Hey guys,

Was there a solution here that you would be able to share?  I'm noticing the same result as described by Invictus.   The fur being rendered is very noisey especially in the indDiffuse and DiffuseEnv on furry characters.  Much more than the non-fur assets.  Lifting indirect and direct sampling helps a little while adding a lot to the render time.

I went as high as 36 samples x 20 Direct x 20 Indirect and Occlusion 128.

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#7 2017-03-08 11:40:22

hulud
Guerilla dev, the guy to hug

Re: Noise on char with fur (Yeti)

In the Invictus case, it was small meshes with incandescance used as lights. They turned them into mesh lights and it solved the problem.

You may try this to solve noise issues in the hair shader :

- Make sure you use the Hair shader and not the Surface nor the Curve shaders.
- Make sure you don't have incandescant meshes lighting the scene, turn them in mesh lights.
- Use "Separate Sampling" on your lights, some pathological lights may generate noise if not separated.
- Avoid to use the Diffuse layer of the Hair shader (it is deprecated, slow and noisy, prefer the multi scatter layer)
- During your test, try to increase first the global "Samples" settings and let the camera samples to 0x0 (automatic). When you are fine with the noise, reduce the camera samples to optimize the render time. Let the Occlusion node at 1 sample in this case. The optimal settings in GR 1.4 are a square number of camera samples and a multiple of that number in direct samples and indirect samples.

If you can, send me a sample of your problem, I'll give you more advises.

Best !


Cyril 'Hulud' Corvazier
Guerilla developer
http://www.mercs-eng.com

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#8 2017-03-08 17:20:42

bonovasitch
Member

Re: Noise on char with fur (Yeti)

Thanks, Cyril.

Can you clarify further about optimal sample values?

1) is the global "samples" best to be of 2 to the power of n?  or powers of 2?  or any integer?  Does the same go for separate samples on lights?
2) you mentioned camera samples are a square number so, nxn.  Then, a multiple of that number in direct and indirect?  Does this mean if I need 8x8 camera samples then I should use 8, 16, 24... for direct and indirect samples?

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#9 2017-03-28 22:27:06

bonovasitch
Member

Re: Noise on char with fur (Yeti)

Hey Cyril, another question about the hair shader...

You mention avoiding the use of the diffuse layer because it is deprecated.  However, I struggle to get the look I'm trying to achieve without the diffuse layer.  I'm trying to achieve something more like a plush teddy bear look. 

Maybe this is something that the hair shader was not intended for?  It seems to be designed for human hair.  Do you suggest developing a different shader for fur?  it would be great to get some roughness controls like those described in this paper,
https://benedikt-bitterli.me/pchfm/pchfm.pdf

Am I missing something?

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