Steps to reduce foam.

[fingerindustries]

Hi all.

Following on from my previous thread about a flushing toilet, I ran a 15 hour simulation over the weekend. While the water has come out great and I'm happy with it, there is FAR too much foam.

How can I reduce this? I'm aware of the Re-Simulation feature but I'm quite certain of how to use it.

What would the exact procedure be to keep the water but reduce foam amount?

Thanks!

Chris.

[Ivaylo Katev]

the foam does not produce impact on the water, you can resimulate with no worries.
you are using the default foam birth, arn't you? in this case to decrease the foam decrease the birth rate, for example if you foam is 5 times more than you need, decrease the birth rate 5 times.
i would recommend to use full simulation, instead the resimulate option. if your foam is really big in count (2-3M or more) almost all the simulation time was spent for it, there will be no significant difference between simulation and resimulation.
in other hand, the resimulation may produce different foam count than the one from normal simulation.

[fingerindustries]

Thanks for the help, I decided it would just be easier to redo the entire sim in the end like you said, with half the foam.

...So in what situations would the re-simulation feature be useful?

[Svetlozar Draganov]

One of the benefits is that you could use it to generate a completely new Foam/Splash particles without having to recalculate the entire simulation.
And another one is that you could increase the grid resolution if case you are happy with the actual simulation but you want to add more details.

Here you could find more information on that matter:
http://help.chaosgroup.com/phoenix21/resim.htm

[ivaylo.ivanov]

The resolution can be increased only with fire/smoke simulations. With fire/smoke you can do also other stuff like changing the discharge parameters of the source without full simulation. But for liquids, it's limited to foam/splahses resimulation.

[Ivaylo Katev]

...So in what situations would the re-simulation feature be useful?

i suppose you ask about the particle resimulation?
it is useful when the particle count is low and the foam simulates much faster than the liquid.
even assuming that it is always more or less faster, you have to make one base resimulation to measure the foam birth, and after that second simulation with birth rate targeted to the desired particle count.