FLIP Velocity by Normal

[ParticleSkull]

Hey guys,

Is there a way to control the FLIP's particles velocity based on the normals of a scene object?

 

To be more specific:

I have this grid and as soon as the particles get closer to it's surface, the particles start flowing on this grid's normals direction.



Thx,
Alvaro

 

FLIP normal vel.rar

[Navneet Arora]

Yes, just plug this into fluid source , select source flip as default source and under velocity volumes tab just replace v with N and your are good to go.

[mestela]

not sure if its the best way for flip, but I took your grid, created a vel field from @N with a vdb-from-polygons, and used a 'source volume' to bring that into the sim. seems to do what you're after.

 

FLIP_normal_vel_fix.hipnc

Edited April 5, 2016 by mestela

[loopyllama]

Yet another solution: flip is just particles so you can create your vel field in sops and advect the flip particles by the volume.

FLIP normal vel_popadvectbyvolumes.hipnc

[ParticleSkull]

Guys, you're awesome. I'll check it right now 

[ParticleSkull]

Matt, thank you very much, your example is exactly what I was looking for.

Jim, thx! It's an excellent example but the volume advection works as a noise, right? In fact I need the particles go in the direction of some pre defined normals. I've painted those normals using the Comb sop.

Navneet, thx! I just don't know how to plug this into fluid force. I've tried to find how to do it but could only find it interacting with wires.

Cheers,
Alvaro

[loopyllama]

Hi Alvaro, You can use any points and any normals with my setup. Just throw in a wrangle with @v = @N; before the fluid configure and turn off that curl noise. easy!

[ParticleSkull]

True, easy busy. Thx!!

[nigelgardiner]

Hi All

 

This is really helpful thanks.

 

Just a quick question.

Matt, in the grid object why do you need to do the attribute transfer routine?  Couldn't you just go Grid to Comb to  AttribVop?

 

cheers

Nigel.

[mestela]

Yep.

 

That was in Alvaro's original setup, I just tried to do the minimum changes possible to make it work. I'm sure he has his reasons for all that other stuff.

Edited April 10, 2016 by mestela

[ParticleSkull]

Hey Nigel, that's to blend the the old normals (pointing upwards) with the new ones (painted with the comb sop). There's no need to use that, I just did it to be able to get a good Print Screen of the normals and show you on which direction it was pointing.

[nigelgardiner]

Oh right,thanks Alvaro, wasn't sure if i was missing something.

Does anyone know if it's possible to use a similar technique to direct an emitting fluid source?

I know the source volume has a velocity volume in it which gives an initial velocity value which is useful but i was trying to figure out if I could use Matt's technique in a similar way to drive the emitted fluid rather than using forces?