Flow along the surface

[Thein Win]

Hi 

 

Can anyone help me on how to drive fluid to flow along a surface and also direct fluid to where we want it to flow?

 

I want it smooth with no splash like water.

 

Example, just like from the tv show Daredevil intro scene.

 

Please 

 

Thank you.

Edited March 21, 2016 by Thein Win

[Thein Win]

Picture below is the problem I am getting. I want it to flow down to the torso, arms and hands. How can I control?

[Farmfield]

There's a couple of different ways to do that, the simplest way is probably creating a velocity field from a point cloud and use that to guide the FLIP particles. Add a scatter to your object, make sure it inherits the object normals. Then use a VOP and in that you'll invert the normals and blend them with a downward vector. Use a bind export to pipe the value into a custom attribute. Now you can use that point cloud with the custom attribute as a force for directing the FLIP particles, use a POP VOP connected to the particle velocity input in your FLIP solver and import the point cloud and pipe your custom attribute into the force for the geometry VOP output.

 

It would look something similar to this, and this is showing the force as normals...

 

 

You could use volumes similarly, converting your model to a volume then using the volume gradient as a force, though using a point cloud it's just easier to control the direction of the velocities as well as it's nice to be able to set these things up as normals and then just pipe them into a custom attribute, that way you can use the show normals flag for guidance in the viewport, no need to set up custom guides for your custom attribute, keep it as normals to the point where you shift it into a bind export with a custom attribute name.

Edited March 21, 2016 by Farmfield

[sebkaine]

if you want to get nice and clean liquid flow without any splash exactly like the daredevil stuff ,

my xp tell me that it is extremely hard to do with FLIP because Houdini FLIP miss the surface tension feature 

 

The concept is describe here

http://dl.acm.org/citation.cfm?id=2019408

 

The shot you mention was done in realflow and realflow does support this.

 

If i had to do this in houdini i would go the cheating way 

i would sculpt reference mesh , generate their SDF and propagate POP along that SDF  

Basically what johnny describe with the volume gradient would be my first choice , but only with POP no FLIP.

 

You could try to go the hard way with FLIP and if you suceed don't hesitate to share your tricks !

 

Cheers 

 

E

Edited March 21, 2016 by sebkaine

[Thein Win]

Can anyone please help create a hip file of what Johnny has suggested, on a simple geometry. I am sorry is my bad for not being able to fully understand.

[sebkaine]

Check those one by christianW as a starting point

http://forums.odforce.net/topic/23278-what-are-signed-distance-field-sdf-and-isooffset/?p=137246

http://forums.odforce.net/topic/17154-are-there-any-resources-on-volumes-alone/?p=104274

 

i will try to assemble a hip when i have some time (not in the next 24h ... )

 

Cheers 

 

E

Edited March 21, 2016 by sebkaine