Non-mixing but interacting fluids

[henning]

Hi!

I'm trying to find out how to simulate two different kinds of fluids that interact but won't mix. I've seen the tutorials and examples, but they are about mixing two fluids (milk and chocolcate for example).
Can two simulators depend on each other? I need two different fluiuds colliding with completely separate meshes.

Can it be done?

[slavina.nikolova]

Hey,

In Phoenix, a Simulator sees other Simulators in the scene just like any other deforming mesh geometry. The loaded cache data into a Simulator represents the Isosurface of the Simulator that the other Simulators see.
When you simulate overlapping Simulators, you would often need to run the Simulators in a certain order. For example, you could have two Liquid Simulators, where "Sim1" would be a heavy liquid that would fill the bottom of a container first, and then "Sim2" would be a lighter liquid that will not blend with the liquid from Sim1, but instead will spill over it and float on top of it. In this case you need to run Sim1 first, and then when you run Sim2 it would by default see the liquid of Sim1 as an obstacle. This way the new liquid would spill over Sim1's Isosurface. Once you already have a cached simulation for Sim2, you must consider that Sim1 now would also see the liquid from Sim2 as a Solid obstacle by default, so if you run Sim1 for a second time, without changing any settings, it would produce a different simulation from the first time it was run. In order to avoid this, you have to make Sim1 ignore Sim2's Isosurface - so you could exclude Sim2 from the Interaction rollout of Sim1. So then, when you want to change how Sim1 behaves, you would need to first run Sim1 and then also run Sim2 after that, so Sim2 would interact with the new Isosurface of Sim1.
You can find more info about this approach here - https://docs.chaos.com/display/PHX4M...een+Simulators

If you don't necessary need to use two different Simulators, but only one instead, you can try the method explained in this video - https://youtu.be/jfE66K-vqYE


Hope this helps!

[henning]

Thank you for the video Slavina!
But how would I send my two fluids along individual paths (using FollowPath), sometimes passing the other very close, when I have them in one single simulator?

[Svetlin.Nikolov]

Hey, would this help?

[henning]

Thanks, nice to know!