Fluids: using 2D smoke to form an image

[MaDSheeP]

is it possible to use spline shapes.. and add some kind of gravity to the splines?

[alexx]

it is possible to use fluids as goals for particles..

so create your fluids, and make them goal for a smoke like particle system.. then add a second goal to the particles which they then later are attracted to..

the other way around would be cooler (being able to make the fluids follow a goal) i think but like that it could work.

cheers

alexx

[bjoern]

I think it is possible, but now i only can import Luma and Alpha Channel

Fluid Effects --> Add/Edit Contents --> Paint Fluid Tool (OptionBox )

under the Tap: Attribute Maps --> import
you kann choose your image.

Ask "Duncan" he is a Fluid specialist!!!

bye
bjoern

[tomb]

Thanks for the replies!
Well I checked out the paint fluids tool and I was able to import the image to the color attribute of the smoke and it worked! The catch is it will set the initial state of the fluid to whatever state the fluid is in when you're painting it. So I'm half way to the effect. Maybe I could run the render in reverse :) .

[Duncan]

OK, if I understand correctly this is a tricky problem. Normally one would use the paint fluids tool to set initial state, cache the simulation and then connect a time node with reversed time. To create the new time node:

createNode time
connectAttr -f time2.outTime fluidShape1.currentTime

On the newly created time node key the time value to the desired reversed range.

This is good when you want the simulation to go from
CHAOTIC -> ORDERED

However I think you want the density to evolve from ordered to chaotic while at the same time the color goes from chaotic to ordered. This is quite a bit harder.

One method might be to use 2 fluids. On the first fluid run your simulation forward, cache(no color grid) and reverse as described above. Now on a second fluid( this one with a color grid ) run it forward to the final frame. Use the paint fluids tool to load your texture into the color grid and set initial conditions. Now apply the first(cached+reversed) fluid as a force on this fluid. On the second fluid disable any other forces you had applied, as well as make the buoyancy 0 and the velocity Damp 0.5(play with this to get the motion right). In order to reverse the direction of the applied force make the velocity scale on the second fluid -1,-1,-1. The two fluids should be exactly overlapping so that the force is applied properly.(you could increase the sizeZ of the force fluid to insure it overlaps the second)
Now when you run the simulation the second fluid should roughly match the motion of the first (both moving in reverse motion ). You can now cache the second fluid and reverse it in time( to make it go forwards ).

I'm not sure how good the density animation will look on the second fluid. The simulation tends to diffuse over time, so I doubt you can get it to scrunch up in an exact reversal. You might create the second fluid as a fluidTexture2d planar projection mapped to the color of the first fluid.

Duncan

[tomb]

Wow thank you Duncan you are a genius. :applause: :applause: :applause:

This is the result. The smoke doesn't come from the emitter like before but I like this effect better anyway :) ...

[ThE MaStEr Of DyNaMiX]

it is possible to use fluids as goals for particles..

so create your fluids, and make them goal for a smoke like particle system.. then add a second goal to the particles which they then later are attracted to..

the other way around would be cooler (being able to make the fluids follow a goal) i think but like that it could work.

cheers

alexx i heard that i can attach a particle to a goal, but can i attach a fluid to a goal ??!! besides i cant see a "goal" in the fluid option box !!!

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