Low light render in cycles, with emission light of Mantaflow's fire (only) | Polyfjord Viewport Community | Page 1

ashen crystal Sep 23, 2022, 5:59 PM

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Hey there, I want to make an animation of a mystery dark castle tunnel with a lot of torches in it. Ofc the torches need a flame and I want to use only the light of the torches in the scene. But unfortunately the results in cycles are horrible. The most annoying point is, higher samples are ending in more horrible results because of the denoise. But without denoising is not really an option, because there would be orange particles everywhere. So- does anyone know a good way how to make a low light scene with fire in it? Or is it just 10.000 samples and render the frames for 2 days?

warm widget Sep 23, 2022, 6:03 PM

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a 1000 samples should do it

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and denoising is garbage for darker scenes

ashen crystal Sep 23, 2022, 6:05 PM

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alright, thanks. I'll try it

ashen crystal Sep 23, 2022, 6:23 PM

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@warm widget any tips for the amount of light paths? Btw tried 1000 samples without denoising but it's to less. Have to go higer

tall rampart Sep 23, 2022, 6:27 PM

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Maybe add an area light of the same colour as the fire

ashen crystal Sep 23, 2022, 6:28 PM

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Yeah, I did that already- also in the rendering, you can see here. But that doesn't really helped the result

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Alright, so here we have 1024 samples without denoise

warm widget Sep 23, 2022, 6:32 PM

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omg

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increase the fire brightness

ashen crystal Sep 23, 2022, 6:33 PM

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and here we have 64 samples with denoise

ashen crystal Sep 23, 2022, 6:34 PM

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warm widget increase the fire brightness

any specific value? I'm going with the emission of mantaflows fire

warm widget Sep 23, 2022, 6:34 PM

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1000?

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whatever works

ashen crystal Sep 23, 2022, 6:35 PM

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Checked some tuts for setting up fire emission

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having 30.000 atm...

void agate Sep 23, 2022, 6:44 PM

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Try to use Fast Gi and 4 Total light bounces should be good enough

void agate Sep 23, 2022, 6:46 PM

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ashen crystal Checked some tuts for setting up fire emission

And I dont know if you even need a volume for the underground emission, Try to replace the top principle volume with an emission node. It might look less accurate but It´ll be faster. Just compare the 2 settings and see whats the better trade off

ashen crystal Sep 23, 2022, 6:48 PM

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I'll try. Thanks! 🙏🏼

warm widget Sep 23, 2022, 6:59 PM

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tbvh you can get away with using stock footage of fire

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ive gotten away with it many times

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and it often looks much better in camera

ashen crystal Sep 23, 2022, 7:00 PM

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Here we go. I raplaced the upper volume node with an emission, increased it to 100.000, checked GI fast Approximation and increased the samples to 4096... still not satisfied

ashen crystal Sep 23, 2022, 7:01 PM

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warm widget tbvh you can get away with using stock footage of fire

What do you mean? Are you changing the flame with an image plane?

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I mean... I could just delete the upper emission node, so the fire does not create light around it and simply just add a light with some noise modifyer on the power. Not that satisfying but I guess that should work. But I hoped there is a better, simpler solution of this

warm widget Sep 23, 2022, 7:04 PM

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ashen crystal What do you mean? Are you changing the flame with an image plane?

yes

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use fire stock footage in place of the fire volume

ashen crystal Sep 23, 2022, 7:07 PM

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what does it do then? Does it use the rgb + luminance value of the image plane (stock footage) for the light shader of the flame?

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so you think the problem here is the emission light? Which seems to be difficult to handle for cycles

warm widget Sep 23, 2022, 7:08 PM

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yes

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especially in dark scenarios when you specifically want only the fire to light the scene

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use this as reference

#Low light render in cycles, with emission light of Mantaflow's fire (only)