Gravity Strength

[superrune]

Hi,

I'm playing around with FumeFX again, doing dry ice (again). I got the feel of the smoke hammered now, and it flows and renders quite nice. However, there's one little thing I'm curious about...

Am I right in assuming that gravity is what pulls smoke upwards, so heavier smoke moves faster? And that buoyancy is a force that stops the smoke from moving too fast (kind of like air resistance). With that in mind I created a gravity helper object, and rotated that upside down, so that the smoke would fall downwards. That worked great. I then wanted the smoke to billow more out/expand, and not necessary rush downwards, so I dropped the gravity to 0.1, and I set the buoyancy to 0.1 as well. However, the smoke keeps going downwards at quite a speed. I could reduce the speed by lowering the Time Scale, but I want the smoke to be expand fast - only not downwards.

Could anybody give me a hint on this, something else I could do to keep the smoke from moving in a direction, just expanding?

Thanks,
Rune

[superrune]

Isn't it weird how posting at a forum sometimes can trigger a solution in the brain - even though you had no clue before posting.

I remember reading about the temperature, and that high temperatures cause the smoke to rise faster. Of course, setting the temp to half it value solved things for me. Problem solved

Rune

[sitnisati]

Hello,

Those two parameters - gravity and buoyancy have the same effect as they do in the nature.
Buoyancy is caused by a hot gas, so to affect it, you basically need to affect the temperature.

Regards,

Kresimir