Underwater Bubbles

[arcana_oblivium]

Hello everyone,

I'm new here and I'm also new in Houdini and procedural workflows in general, I have experience with 3D in general but not so much with simulations and those kind of stuff. Now, I decided to start my Houdini journey with a small project of mine that involves a rising bubble simulation from underwater. I'm currently on the process of binge watching several tutorials on Flip Fluid simulations inside Houdini but I need your guidance on how you would approach such a task.

Thank you all! (please be patient with my lack of knowledge)

[Vinz]

Hello

I am new to Houdini too and I am also bearing the cross of total lack of knowledge BUT I am currently working on a raising bubbles/fluid simulation as well and it works.

The approach that worked for me was pretty straightforward and is as follow:

Create 1 simple Flip simulation (Flip fluid in a container of your choice)

Create 1 separate Pop particle system (without gravity) to emit particles from a geo such as a curve circle located inside the actual fluid. Attach ('copy to points' node) a simple sphere to your particles. Set your birth rate and sphere size according to something realistic. Set the initial Y axis velocity of the spheres so they raise up to the surface of the liquid at a reasonable pace and balance their life expectancy so they die right at the fluid surface. Turn off their visibility (display off at obj level).

Source the fluid container as a collider for the particles inside the Pop network (static object).

Back to the Flip sim Dop network. Create a 'deforming' collider object, that are the SPHERES. The sheres will deform naturally in the fluid (won't stay perfeclty round).

Play it

Depending on the scale of your scene, your particle resolution and your pop particle velocity it will likely explode at first. The first fix is to dampen the velocity at Flip level by lowering the 'velocity scale' param in the collision tab of the flipsolver.

 

Let me know if this turned out ok for you and if anyone else has any tips as to this matter please feel free.

V

 

 

Edited June 30, 2020 by Vinz

[ziconic]

If you are looking for something out of the box, you can try the "enable air incompressibility" option in the FLIP solver, as described here: https://www.sidefx.com/docs/houdini/fluid/bubbles.html

Note that I had to turn on viscosity and surface tension to prevent the air bubbles from collapsing right after they are born.

[evanrudefx]

Hello friend! I have a hip file available [for free of course] here:

hopefully this can help you get started
 

 

[ziconic]

Thanks for sharing your setup! One thing it made me realized was that, in addition to having a sufficiently small particle separation, turning *off* "Solve Pressure With Adaptivity" can help prevent air bubbles from collapsing.

Btw what was your motivation for using the gas vortex confinement DOP? Was it to help break up the bubbles even more?

Edited July 8, 2020 by ziconic

[bjzhangzhe]

this one.

https://www.youtube.com/watch?v=17z5oZCpPeA&t=8s

[evanrudefx]

it makes the water swirl more like if you use that on smoke.

[arcana_oblivium]

Hello everyone, I was away for a week and couldn't reply to your beautiful answers! Thank you all so much for sharing your ideas and knowledge. What I ended up doing is following John's tutorial shared by bjzhangzhe but I'll try all the suggestions as well as it will help me improve vastly! Again, you are all amazing, thanks!

Edited July 7, 2020 by arcana_oblivium