# Pop Noise Amplification More On Slower Particles [SOLVED]

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The following expression on a popwind dop node will make the faster moving particles have more amplitude according to the noise settings:

`amp = length(v@v);`

But how can I go about making only the slower moving particles be more affected by the pop noise?

Instead of just using a general if statement to say if particle speed is less than a certain amount, then have noise applied.. I'd rather the amplification of noise be more apparent as the particle speed gets lower.

Thinking back on this, maybe it does not make sense at all.. If a slow moving particle is then pushed around faster by the noise, is it then considered as moving too fast and therefore the noise should not be applied? Have I thought up an impossible noise equation here?

Edited by GlennimusPrime
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if(length(@v)<ch(“threshold”)) amp *= ch(“scale”);

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amp *= fit(length(@v),.5,2,3,1);

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Both of these are yielding good results. I initially thought an if statement wouldn't quite do it for the sim, but it seems to be going in the direction I'm after.

Thank you!

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• 2 weeks later...

If you're afraid having an if statement, you can also try with a lerp, which will do this way more gradually.

float speed = length(@v);

float normSpeed = fit(speed, 0, chf("max_speed"), 0, 1);

amp = lerp(amp, 0, normSpeed);

If you feel like the results are a bit too linear, you can always run your normSpeed through a power function, wich will make it more interesing in many cases i think.

Still new to this, I might say some bs, and would love to get corrected if so.

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