How to adjust the direction and trajectory in AE？

[chineseboy]

i love the effect of “T&P Intro”
i feel it very cool
but i don‘t know how to adjust fog's direction and trajectory in AE，
i’m a chinese
can you help me?
if you help me,i will happy !

Cheers

chinese-boy

[jascha]

You can use velocity inputs to blow the fluid into several directions. See the manual for a detailed description of how these work.
You can also use gravity and buoyancy settings to let the density and heat move the fluid up or down. But the velocity inputs are more flexible.

[chineseboy]

Thank you very much
You are a good person
I know used gravity and buoyancy settings to let the density and heat move the fluid up or down
but i mean is not only let the density and heat move the fluid up or down
i want to let the density and heat move the left or right
the density and heat move the fluid left or right in effect of “T&P Intro” video
can you help me？
jascha

[jascha]

Check out the velocity inputs. They allow you to blow the fluid into any direction. See the manual for details.

[feniks]

A tip on how to use velocities I found is

- create a new comp the size of your original composition, call it "velocity"
- create a layer like 250x250pixels in your comp,
- apply a 4-color gradient to it
- place the sources at the corners
- change the colors to

upleft -> R 0 G 255 B 128
upright -> R 255 G 255 B 128
downleft -> R 0 G 0 B 128
downright -> R 255 G 0 B 128



- create a layer the size of your comp
- apply Generate > Fill and use the picker to pick a color from your 250x250 pixel layer
whereas the middle point of the layer is your x/y velocity 0,
if you pick a color more to the left your source will blow to the left, more to the right your source will blow to the right etc for up and down
- hide your 250x250 pixel layer once you start simulating.
- go back to your original comp, put the velocity comp inside it, turn it invisible
- on your smokelayer choose the velocity comp as velocity source.

You can play around with gradientmaps, fractals, turbulent displace etc. inside your velocity comp to make more randomness to your velocities.
Or use the velocity output of another smokesimulation to drive a secondary smokesimulation.

Another tip I found to give your simulations more detail is using animated fractals on your source so you get more random emission.