Modulating an animated volume


so, as mentioned in my previous post I have a simple soft body sim of a sphere hitting the ground and I need it to emit steam. I got it all working but I’d like to module the surface a bit to break things up.
If the volume were static I’d multiply a PerlinNoise node with it, but since it’s moving, the volume (ball) would be moving through the noise.
I’d like it to stick to the surface though (which is deforming).
So in other words, I have an animated sphere emitting steam, but I only want it to emit from random areas on it’s surface not everywhere.
Can I texture it with a noise and use the texture values to drive where steam is emitted?
Now that I’m writing up the question I feel like Matt or Ronnie showed me how to do this in the past - but I can’t remember.


Hi frank!
In some situations you can link the transform of a perlin noise to the animation and have it ‘stick’ but in your case as its soft you would need texture emission.
Until the UV/Texture emission is upgraded in Eddy, i would suggest emitting particles through your noise, and then use particleToVolume to do the eddy emmision. This is how i’m doing almost all moving emitters these days, as there’s more control over velocity, and also correct substeps for fast stuff if there is a Particle Settings node in there.
Happy to help you build up a script if you want to email me the data.

Thanks Matt,
you mean texture the animated geo with noise, then let that emit particles, which in turn emit an Eddy volume?! Clever, I will give that a go.


Heres a particle setup that uses noise if you need for reference.