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View Full Version : ground Fog using Fluids/ Particles: Please help!


decadeone
09-01-2004, 09:19 AM
Hi,

I want to make a ground fog (with a small heigth) which flows through a forest towards the cam. Later when the fog on the ground has reached it it should rise up and cover the whole forest with fog.

The problem with the fluids is that i can't hold them down on the ground. The collissions of the ground and the trees push the fog up too much.

I also tried to make the fog with a surface flow and particles but there i wasn't able to create collissions with the trees.
Moreover i can't make a good looking collision with normal particles because i don't know how i could let the particles collide like fog on the trees. They have to flow around it. Any idea?

You could download the fluid scene here to see what i mean.

http://www.decadeone.com/groundFog.mb (http://www.decadeone.com/groundFog.mb)

Thanks for help.
Chris

lubiya
09-01-2004, 10:52 PM
at the place of each tree, put a small field (radial, volume axis, etc.), and by using the Max Distance of each field make the particles to flow around the trees.
this way, you don't have to collide the particles with trees and you'll have much more control over them.

decadeone
09-02-2004, 08:34 AM
thank you so far.
If I solve it like this the problem is that the particles indeed are pushed away from the trees but behind the trees they do not flow together again. How could I solve this?

Beside that, is there another possibility to let the particles flow along the surface than "surface flow" because this feature controls the whole particle movement....?
I don't want the particles to jump from one collision of the ground to the next..

lubiya
09-02-2004, 02:34 PM
ok. maybe you can use Curve Flow. just create curves that flow along the surface and go around the trees. and assign the same particle to all the emitters in the curves.

this way you don't have to deal with stupid particle collision jumpings and you can take your particles wherever you want :)

Duncan
09-08-2004, 08:20 PM
To keep the fluids more on the ground, you could try making the density buoyancy strongly negative, as well as thresholding the the opacity a bit( move the left indice a little to the right ).

Another option is to use the fluids as a force on your particles ( i.e. don't render the fluid ).
Make the particle conserve value low when doing this so the particles closely follow the fluid flow. You can add gravity and ground collisions to the particles to keep them from flowing up.


Duncan

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