volumetric noise falloff not acting they way I want

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I'm currently experimenting with volumetrics and falloff. In this specific example I made a simple falloff on the Z-axis and added basic noise. Whatever solution I come up with, I can't actually get what I want. I want to basically have no noise affecting the density when density is 1 (or higher). Is there a way to get this right?

Edited by rove - 2021年10月2日 06:45:35

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noise_faloff.png (554.6 KB)

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Try the min function instead:

f@density = min(z, n);
https://procegen.konstantinmagnus.de/ [procegen.konstantinmagnus.de]
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you are trying to multiply with noised values, even if you add your ramp to the noise, its still gonna vary using the noise values
like 0.1 + 1 = 1.1
0.5 + 1 = 1.5
...

so instead you can blend the noise and density using your ramp, which will make sure that where the ramp is 1 you get clean input density and where its 0 you'll get full noise values:
f@density = lerp(basicNoise, f@density, zDensity);
Edited by tamte - 2021年10月2日 12:44:28
Tomas Slancik
FX Supervisor
Method Studios, NY
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tamte
you are trying to multiply with noised values, even if you add your ramp to the noise, its still gonna vary using the noise values
like 0.1 + 1 = 1.1
0.5 + 1 = 1.5
...

so instead you can blend the noise and density using your ramp, which will make sure that where the ramp is 1 you get clean input density and where its 0 you'll get full noise values:
f@density = lerp(basicNoise, f@density, zDensity);

Thanks for the clarification! This makes me feel like I should have just paid more attention during math classes way back at school. It's never too late though ;-).
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Konstantin Magnus
Try the min function instead:

f@density = min(z, n);

I'll give it a try!
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