I want to add velocity to normal direction in smoke sim

[Kobayashi]

Hi guys.

I want to add velocity to normal direction of smoke's source mesh in smoke sim, I tried by "point sop" and "vop force" but I didn't fix it. I can do this for popnet It was so easy.

I need to set key frame that velocity so I'd like to this by vex.

Do someone have idea? help me please!!!

thank you.

Edited August 28, 2016 by Kobayashi

[fencer]

@N = @N; //just in case
@v = @N * ch("anim");

Edited August 28, 2016 by fencer

[Kobayashi]

Thank you for reply me.

I need to ask one more thing, How can I use that expression ?? I think I don't have normal attribute inside dopnet.

sorry I don't really understand Houdini yet.

 

 

[Yon]

Hi, in this file you will see how to bring the N of your geometry into dynamic network and apply it to velocity of pyro sim.

there is also a Mult parm on the wrangle you can keyframe to control normal strength

untitled.hipnc

[Kobayashi]

Thank you so much for your kindness!!!

That is just what I want however, I got some question,, You write advice and something on sticky in Houdini.

You said that "We use the N, but often you can use v, the velocity of a particle system."

is not "Use N" so cool way? so, should I make v attribute in sphere geo what move normal direction? or something? sorry if its stupid question. 

Like this scene what I uploaded

but my scene is not good,,especially moving normal directioin

making_HDA_smoke.hipnc

Edited August 29, 2016 by Kobayashi

[Yon]

Using N of a geometry is good, you do not need to make v for your geo

they are different things, both good - its only a choice

normal is most used as static direction - it does not move.

If your moving your smoke against a wall, pushing it down a path - simply moving your smoke by geometry that does not move, N is good.

But say you animate your sphere, its movement is stored in velocity. Using v will make your smoke move like your animated sphere.

Or you can push your smoke around by a particle system.

all is good and cool  with time it will be familiar to you

[Kobayashi]

ah! okay I got it 

thank you for your help!

sir Yon and Fencer!