View Full Version : Turbulence field - how exactly does it work???

05 May 2008, 01:44 PM
Hello. :wavey:
I am new to Dynamics in Maya and I am learning, following tutorials, etc., but unfortunatly there is something I just cannot understand.
Can someone pleas explain to me how does turbulance field work?
I know it adds randomness to the particle motion, but I still can't figure out some of it's attributes.
It's frequency, phase, noise level and noise ratio! Even if I change these attributes I can't see what does each of them actually do.
I looked in Maya Help, but it still didn't help me understand. :banghead: I hope you can help me!

Thanks in advance! :thumbsup:

05 May 2008, 04:26 AM
Probably the best way to visualise turbulence is to setup a poly plane with subdivisions of 100 x 100. Then convert your plane to a softbody only and connect a turbulence field to your particles. Set your timeline to say 50 frames and push play. Change the settings, rewind and push play again to see the changes.

A low frequency say 0.1 will give you less detail in the turbulence as if you have scaled the noise up 300% for example. A higher frequncy like 8.0 gives you more noise as if the noise pattern has been scaled down, so more detail in one area.

The phases shifts the noise pattern along in the particular axis. So its quite common to animate these axis in time so that your turbulence appears to move instead of returning the same value over time. For example phaseX=time;

The noise level is the number of lookups (im not 100% sure on this one) The greater the value, the more irregular the turbulence. Noise ratio only kicks in when the noise level is above 0 taking more or less samples depending on its value.

For example if you have a magnitude of 3, no attenuation, freq of 0.1, a noise level of 5, and noise ratio of .75, you will be able to see the added turbulence detail from the noise level kick in.

Hope that helps.

05 May 2008, 09:59 AM
I thing I'm beginning to understand those now. Not as much as I'd want to, but still - thanks!

05 May 2008, 12:18 AM
That is a good tip to visualize turbulance. Another would be to lower your conserve slightly. Particles would start making a trail. You should consider acquiring some of the Gnomon Dynamic DVDs. They cover the basics rather well.

One more thing about turbulance... Think of it as a texture. As far as I know (and someone correct me here), turbulance itself does not deform. You can animate its phase (X Y or Z), which would give you the illusion of an ever changing utrbulance field. Some of the maya shaders and maya fluids have an attribute called "texture time" which varies a look based on time. Turbulance doesnt. When it comes to particles you can also move them controlling their velocity with mel. Some people got great randomity with this approach.

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