Particle separation flip fluids

[vishalvfx]

Hey everyone, 

Trying to wrap my head around flip simulations in Houdini, any help is much appreciated. 

so here is a animation of the sark i downloaded from the very talented Carlos Parmentier, (thank you)

My container is 50x25x55, 

The rest of the setting are explicitely mentioned in the attached QT,  please do take a look. 

 

So here are my questions, 

 

1) as we reduce the particle separation, (increase resolution) the simulation changes quite drastically, so say if i were to test a sim at .2 separation, how do you know what you are going to get at say .075, 

 

2) Is there any way to up rez these simulations without such a drastic change in the look of the sim. 

 

3) I'm sure some of you masters in flip sim, could critique my simulation, and guide me to better them . 

 

4) Other than the shelf tool for a white water sim, what would be the best way to get some white water? 

 

 

Thank you.

 

 

 

[rolfcoppter]

Hey,

 

One thing that is for sure is when you up res your simulation the look is always changing. 

That applies for any solver i have ever worked with in Houdini and any other package as well.

[vishalvfx]

Hey thanks 

So basically this is what you would expect?, Any ideas on how to make it more predictable. 

[pbarua]

Use PointReplicate SOP or Wedge ROP.  

[sebkaine]

one classical approach is to divide in 2 steps.

you make a low rez sim where you devise the global behavior , then you use this low rez sim to drive an high rez one.

 

this is the global principle

http://www.cs.ubc.ca/~rbridson/docs/nielsen-siggraph2011-guidedfluid.pdf

 

i have never done that myself in H but i'm quite sure the workflow can work smoothly in H.

of course you will have to burn some brain cell to make it work ...

 

maybe it has already been done here ? 

Edited June 28, 2015 by sebkaine