Liquid particles number constantly decreasing

[Svetlin.Nikolov]

This means that as the simulation goes, the liquid constantly spills out of the grid as there is no bottom to hold it.

I believe once this geometry is moved up, to the inside of the Simulator, the scene would behave much better.

Cheers!

[Oleg_Budeanu]

Hey folks,

I am dropping in on this issue as well.

Please notice that the bottom of the fountain is OUTSIDE of the simulation grid:

edit - you already answered

I've started the simulation again and I see the particles declining - from 2m (after removing using the Particle Tuner) after ~130 frames of simulation I'm already left with 1.1M of particles.
I will try to do the "real life" scenario. I did not expect this to be so complicated, I might have to search for another solution for simple cases like this tbh.

[Svetlin.Nikolov]

Ah, so in your original scene all sides of the Simulator are jammed, so the particles would be contained inside.

However, you are using the Tuner to kill the particles exiting the "exclude particles" geometry. So as the simulation goes, all particles that spill to the sides get killed and the liquid level subsides.

So why don't you animate the Tuner's ON option to be enabled only for the 1st frame of the simulation (frame -150)? This way it would remove the excess particles from the fillup and then it would let the remaining liquid do its thing?


A completely different approach to the entire setup would be to use the Confine Geom in the Grid rollout - you could use the "exclude particles" as confine geometry there. This way this geometry would act like the jammed walls of the simulator.


The difference between both approaches is:
- Using an animated Tuner to kill outside particles would shape the liquid at the first frame of the simulation and then let it run. Any flying liquid or foam particles that hit the jammed simulator walls would bounce back. If you don't want this effect, you could set the side and top walls to Open, so liquid particles exiting the grid would just disappear, while foam particles could continue living outside if they have the Max Outside Age option set.
- Using Confine Geom would constantly contain all particles inside the shape so any flying liquid or foam particles would bounce back from this tighter shape. If you don't want this effect and want to have the foam particles exit the shape, you won't be able to do that. You could kill the particles near the borders with Tuners or Geometries with Clear Inside enabled in their right-click Phoenix properties.

[Svetlin.Nikolov]

My last sentence brings me to a 3rd approach for this scene - instead of a tuner, you could use non-renderable geometries with "Clear Inside" and disabled "Solid Obstacle" to delete particles that enter them.

This could even speed up the simulation as the tuners might be slower to compute as they are more universal and allow you to control things such as the distance inside or outside of the object, while geometries with Clear Inside would simply kill particles as they cross their surface.

[Oleg_Budeanu]

Thanks so much for the information, that sounds interesting.
I will try all the options and will let you know which one works.
Regards