Boiling water

[henning]

Hello!

I want to create boiling water using Phoenix FD 3.
I'm aware of the bubble example scene but I'm more interested in moving the fluid instead of creating bubbles.
My approach is to simulate Bubbles of air using a smoke simulator and then using the resulting velocity field to move the Liquid Simulator.
Do you see any problems with this workflow? What is the correct way to set this up?
I'm working in a 15cm x 15cm Liquid Grid but its scene scale scale is set to 5.
How high would the smoke velocity have to be to properly excite the fluid?
Does the smoke sim has to have "solid object" enabled?
Does the Motion velocity Effect value on the smoke sim simply multiply its velocity field?

[joshclos]

That will be a super fun effect to create. I think you're main idea is good - to have a secondary sim drive the fluid sim. But I'm not sure how to use a smoke sim as a force for a liquid sim in Phoenix. You could do something like this example that was done in Realflow: https://vimeo.com/11046292 - the resulting render: https://vimeo.com/10772406

If that is your desired effect, you could do something similar by creating a small "patchy" sim of some fluid moving upward like in the example, then mesh it and use that mesh as a collision for the main sim. Then those meshed collision objects would be rendered as refractive geometry, creating bubble-looking things. Or something like that.

[Svetlin.Nikolov]

One of the things we need to add in the near future is a force helper much like the body force or the path follow, which takes a cache sequence and allows you to drive the simulation using velocity from thise cache sequence...

[henning]

Oh in my mind "simple" sampling of another sims velocity field would already exist, but the only way to transfer the velocity is via meshing (or just enabling meshing on smoke sim and enablig solid object)?
What about using PhoenixFDTexmap? This already does sample any wanted value that you hopefully could map to the fluid sim using a PHXMapper. Would that work? I'm going to try that.

[Svetlin.Nikolov]

Good idea! Maybe this would do the trick as well.

[henning]

Good idea! Maybe this would do the trick as well.

can you confirm that the liquid sim can be mapped with a PhoenixFDTexmap in a PHXMapper? I'm not getting any effect and I'm wondering whats missing.

[henning]

That will be a super fun effect to create. I think you're main idea is good - to have a secondary sim drive the fluid sim. But I'm not sure how to use a smoke sim as a force for a liquid sim in Phoenix. You could do something like this example that was done in Realflow: https://vimeo.com/11046292 - the resulting render: https://vimeo.com/10772406

If that is your desired effect, you could do something similar by creating a small "patchy" sim of some fluid moving upward like in the example, then mesh it and use that mesh as a collision for the main sim. Then those meshed collision objects would be rendered as refractive geometry, creating bubble-looking things. Or something like that.

Thank you!
But I tried that and the way I'm doing it seems to eat the liquid. Volume loss occurs.

[Svetlin.Nikolov]

can you confirm that the liquid sim can be mapped with a PhoenixFDTexmap in a PHXMapper? I'm not getting any effect and I'm wondering whats missing.

Dang, this really won't work with FLIP liquids because they are particle-based. I hope I can get to the cached-velocity force soon, but there's a lot of other tasks before that...

[henning]

Just for my understanding. I suspected the velocity is being stored in the voxel grid and the particles sample this grid. I just thought I could add external velocity to this grid by sampling another overlapping grid.

[Svetlin.Nikolov]

Actually it turns out it's possible, but I needed to do some modifications to the FLIP solver. I hope in a couple of days this will be in the nightlies and I'll attach a scene as well

[Svetlin.Nikolov]

Hey,

The changes are in the nightlies. You can check this scene as a reference: test_mapper_2014.zip

Hope this helps

[henning]

Thank you very much! I'm currently requesting access to the nightlies...