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Fireflies in Rendering

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Fireflies in Rendering

Unread postby machieb » Tue Jul 21, 2020 11:28 am

Hello,

in recent rendered images I get fireflies. I don´t know why?!
I have only an environment light set to white, no hdri, no lights.
The fireflies filtering option in pathtracer material sampling does nothing. The only way to get rid of the fireflies is to set the clamping mode from path level to the old deprecated intergration level.

I am using Clarisse 4.0 SP8.
I testet also with Clarisse 4.0 SP3 and there are no fireflies with the same scene no changes. But Clarisse 4.0 SP3 uses for clamping the old deprecated intergration level.

Is that a problem that was introduced with one Service Pack after SP3?
Is this a bug!
What do you think?

Cheers
Attachments
Fireflies_SP8.jpg
Fireflies rendered image SP8
Fireflies_SP8.jpg (61.55 KiB) Viewed 782 times
Fireflies_Rendersettings_SP8.jpg
Path Tracer Settings SP8
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Re: Fireflies in Rendering

Unread postby machieb » Tue Jul 21, 2020 11:50 am

So I tested further and found the problem.
There is an object in the scene that has a shader on it that should mimic a transparent plastic.
So good so far, in the geometry tab of the shader the automatic sideness was checked.
And when this option is checked fireflies are introduced in the scene.
Very weired!
Attachments
Fireflies_Shader_sideness.jpg
Automatic Sideness on in one shader introduces fireflies to the scene
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Re: Fireflies in Rendering

Unread postby machieb » Tue Jul 21, 2020 4:22 pm

What does that "Automatic Sideness" option do exactly? I can´t find anything about it in the wiki.
Why is it introducing fireflies into the scene, when it is checked?
Is that a bug?
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Re: Fireflies in Rendering

Unread postby KevinC » Tue Jul 21, 2020 4:49 pm

Hello,

The automatic Sideness attribute appears when you are opening an old scene before the attribute sidedness was introduced. So when this attribute is here it uses the old behavior regarding the sidedness, maybe the fireflies come from this. I don't recall exactly what the old behavior was but I think it was a mix between double and single sided.

Hope this help,
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Re: Fireflies in Rendering

Unread postby esmith » Wed Jul 22, 2020 5:14 pm

machieb wrote:What does that "Automatic Sideness" option do exactly? I can´t find anything about it in the wiki.
Why is it introducing fireflies into the scene, when it is checked?
Is that a bug?


That's an attribute on a very old version of the Standard Shader, make sure you are on the latest version. I don't recommend to have the attribute turned on if you find your scene with a legacy version of the Standard Shader.
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Re: Fireflies in Rendering

Unread postby machieb » Wed Jul 22, 2020 6:26 pm

Thanks, that´s good to know!
I have a shader library with lots of materials, that I created in the last year. So maybe there are a few shader that were created with an "older" clarisse 4.0 version. I will check all shader so that I´m sure the automatic sideness option is not turned on!

Cheers
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Re: Fireflies in Rendering

Unread postby machieb » Wed Jul 22, 2020 6:45 pm

I have to say, that it is a bit sad, that I can´t have a real clarisse shader library because shader that I created a few month ago are not useable anymore or produce rendering problems with higher clarisse service pack versions! :-(
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Re: Fireflies in Rendering

Unread postby esmith » Wed Jul 22, 2020 8:06 pm

Well it's one attribute, that you can easily change. I too have shader libraries, when the new auto desk standard comes out, or material X..or I have to move to Disney Principle or make my maps all streaming, OR NOT...I'm in the middle of moving to ACES I think...color space on hundreds of textures need to change.....

Libraries require work to maintain, and it's why almost no studio on Earth has one even though it's every studio on Earths dream to make one.

Use the search function to find all your standard materials Shit+Select them all, and turn off that value.

I just did it for an old scene of mine, the resulting render required 3 individual shaders to be turned to Double Sided and problem solved. The entire process minus the rest render, including the 2nd fix took 1 minute or maybe 4. :-)
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