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[Request] Cascade 'Noise' Modules, or 'InterpUniformDistribution'

Currently there is no way to simulate randomized noise values into velocity, colour, acceleration, over time. I have discovered a use for these sorts of modules recently while tinkering with Particle Lights and more.

Do demonstrate what I mean, this is an example of a 'Velocity Noise' operator in source engine, into which you input a maximum and minimum velocity, and the engine adds (or subtracts) this 'noise' to the current velocity of the particles. While we currently have Uniform Distributions, there is no value to determine the interpolation time between the values that the distribution generates, nor what the max differences between the old and current values can be at any one time. Here is the example:


Currently, you can use a 'ConstantCurve' distribution on an 'Initial Velocity' modifier (which works in 'emitter' lifetime rather than 'particle' lifetime), and animate velocity to whatever you want over the length of the Emitter's lifespan. However, this results in very predictable results which are not truly 'random'.

Using a 'Velocity Noise' module, would allow you to change the current velocity value of a particle completely randomly, but with some more finite control. Not only this but as the Cascade modules are stackable, you can combine this with Init Velocity, Acceleration etc, which in turn could also have it's own Noise module (Acceleration Noise).


This could also be applied to Colour, which would be especially useful for particle lights in particular. If you want to achieve a 'flickering orb' effect for example, you can either animate the colour of your particle over time as before, which will update the 'Light' module respectively, or you can animate the material itself, which will NOT update the light. If you want to have light that corresponds to the 'flickering' material of the orb, you would have to animate everything manually, which would still produce a predictable result.

I hope this explains what I'm looking for :)

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asked Mar 11 '14 at 01:57 AM in Rendering

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ue4-archive ♦♦ STAFF
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avatar image ue4-archive ♦♦ STAFF Mar 11 '14 at 01:57 AM

Expanding on this, having a separate distribution for 'Interpolation Speed' and 'Maximum/Minimum Value Difference' would allow you to speed up or slow down the noises effect, or make it more or less apparent over time.

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Hi James,

Thank you for your feedback. I have entered a report into our feature request database based on this post and assigned it to a rendering developer. Please let us know if there is anything else that would improve your editor experience.



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answered Mar 11 '14 at 01:57 AM

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ue4-archive ♦♦ STAFF
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