How to increase grid resolution

[Dragonian2]

Hi all,
I'm currently working on a large complex ocean scene, and have over 300 frames of pre-roll simulation in-order to build up the wave motion.
Is it possible to pre-roll the simulation at quarter grid resolution, then up-res grid resolution from frame zero and onward maintaining the wave shape/motion generated by the pre-roll simulation, in-order to reduce simulation times.

Thanks in advanced.

[Adam Walker]

I am from the same team as Dragonian2, I thought I should chip in and help clarify his question.

This is not about increasing the grid resolution in the UI of Phoenix, it is about post-processing an .AUR file to up-res the fluid simulation.

The idea behind this is that a 1/4 resolution sim is used for the pre-pre-roll, the last frame .AUR file in this pre-pre-roll is then doubled in resolution and used as the seed frame for the next pre-roll stage, and subsequently the last frame of this pre-roll is doubled again to form the seed frame for the full resolution simulation. It would allow for large scale wave motion without the need for 400+ frames of full resolution pre-roll.

Another way to illustrate this:
Stage 1 - Pre-pre-roll (frames -400 to -150) @ 1/4 resolution
Stage 2 - Pre-roll (frames -149 to -50) @ 1/2 resolution (using the up-res'ed frame -150 from Stage 1 as the seed)
Stage 3 - Main sim (frames -49 to whatever frame) @ full resolution (using the up-res'ed frame -50 from Stage 2 as the seed)

[Svetlin.Nikolov]

Nope, sorry guys - load & start from a liquid cache does not work yet and neither does resimulation with resolution change for liquids. Both should work for fire/smoke, but for liquids they are not implemented yet. I hope I can find time for these soon.

Cheers!

[Adam Walker]

Just to check, we are not really expecting this is be a robust / accurate approach, this is very much a hack work around to make the pre-roll less time expensive.

Our idea was to just to do a linear interpolation between each cell value on the lower res grid and populate that in a larger grid.

We had a look at the SDK, and saw there were group/particle channel "getter" methods, but we couldn't track down any "setter" methods. Is this an option?

[Svetlin.Nikolov]

Unfortunately no, not yet at least - only way you could manually populate a cache is through maxscript right now, but again - this would work only for grid channels and not liquid particles... I have to think about any other alternatives. I guess Load&Start with a liquid sim would be what you need, but this needs to be implemented for FLIP liquids and I won't be able to get there in the coming weeks.