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lewkiw
11-30-2006, 11:23 AM
Hi,

I am animating a character's breath in a cold environment and using Maya Fluids. I would like to vary the initial velocity of the particles at birth depending on what the character is doing. I don't see any simple way to set the initial velocity on a frame-by-frame basis.

Right now I'm faking it by animating the buoyancy, but this is lame because obviously it's not the same as initial velocity, and of course it affects already born particles not just the newly born.

I've already tried putting a fan behind the emitter, but I'm having trouble controlling it. I would prefer to just animate an "inital velocity".

Thanks,
Sean
Pyrokinesis
12-02-2006, 08:24 AM
Remember fluids are not particles, though you can use flluids to drive particle motion, and shade them.

Using fields with fluids is great, but you must remember flluids are sensitive. I would reccomend using fields at high magnitudes, in quick spurts.

To gain greater control over the fluids using fields, you can also use volume fields, which will limit the effect the field has to only, say the initial creation of the fluid. You can then key the field, or fields, and the emitters density pending the characters phrasing.

But if you still are having trouble getting control, and time is not on your side. Then I would use sprites with a smoke image sequence.
AndersEgleus
12-06-2006, 06:39 AM
Motion fields are great for transfering velocity from objects to fluids (they're basically just drag fields with customized settings for the purpose).

But remember also that if you add temperature to the fluid, either in the form of heat, or fuel which is then converted to heat, you can use temperature buoyancy to make the fluid move fast when emitted but then stop as the temperature dissipates. Same thing with temperature turbulence - you can make it turbulent when its emitted but then calm down as it cools off.
lewkiw
12-06-2006, 10:59 AM
Thanks for the tips guys... I have tried a sprite approach, and it just isn't working for the kind of wispyness we need. I'll try the small field with high drop-off and/or the temperature idea.

Sean
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12-06-2006, 10:59 AM
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