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How to Up-res FLIP TANK sim?


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Hello!

 

When i try to apply up-res from container tools, i get a error

 

'NoneType' object has no attribute 'set'

 

it occur even on a fresh new scene with shelf created default FLIP TANK!

 

on manual say it is possible to up-res flip liquids..look:

 

 "This solver can scale a low-resolution smoke, file, or even liquid simulation into a higher-resolution container"

 

i´m on H13, windows...

it´s a bug?

(i already deleted HOU user folder to try fix, but has no effect on error!)

 

i´m trying to upres a flip liquid simulation, but i don´t know how to manually wire nodes to up-res FLIP sim. 

 

Does anyone have a solution, or a tip to do it manually?

 

Thanks in advance!

Edited by Malcolm Zaloon
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but the manual page say :

 

up-res gas node

 "This solver can scale a low-resolution smoke, file, or even liquid simulation into a higher-resolution container"

Fluid liquids, not particle liquids like flip is.
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up-res tools are designed for voxel based fluids, as in the smoke/pyro/liquid solvers. FLIP is a particle fluid solver and cannot be up-res'd in the same manner.

yeah.. i see..

 

but there is another way to do? i´m thinking about advect Hires container with lowres pre simulated one...

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The apparent geometric resolution of a FLIP sim is defined by the number of particles, not by the grid resolution.

It is possible to simulate a FLIP sim and later re-advect a larger number of particles using the pre-solved velocity fields, and in certain cases that might be beneficial to do.

 

In most cases I would say it probably wouldn't be though.  The problem is, while you'll get more geometric resolution, having a large number of particles moved around by a low-res grid will give you low motion-resolution, which may not be apparent in a still-frame, but when you see the fluid moving, it's almost as important as geometric resolution.  Generally, having roughly 4-8 particles per grid cell is a good balance, and that's what FLIP fluids are typically set up to run at by default.  Any extra time spent attempting to up-res as a secondary process would usually be better used just increasing the original sim resolution instead.

 

This is mostly because in Houdini FLIP simulations, the actual grid-based part of the solve, while still heavy, is actually pretty fast and scalable compared to the time required to handle the particles themselves.

 

From my experience, I'd say when it comes to FLIP, spend the time working up to the result you want, at the maximum resolution you can afford the time to sim, rather than looking for ways to hack it.  Ultimately you'll end up with better, more natural looking results that way.

Edited by danw
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