Phoenix Fd - low res liquid Proxy sim for initial state hi res sim?

[Mirko.Binyan]

Hi Everyone.
I'm new to Phoenix but i know that in fluid sim there is a technique where you can simulate, let's say, the first 100 frames until the liquid settles to a movement, in low res.
Then you can use the final frame of that low res sim as an initial state for a higher res simulation, to save time on the pre roll part.
I've been looking for a while but i can't find any info about it, as i may be using the wrong terms too
Any suggestion/link would be very appreciated!

[georgi.zhekov]

Hey,

There are two ways you can approach that. The first one is what you mentioned - for it to work you need to load the cache with the Load & Start button in the Simulator.
You can find more about it here - https://docs.chaosgroup.com/display/...lation-Actions

The second option of doing it is to fill the simulator at the start - here is a tutorial on how this works - https://docs.chaosgroup.com/display/...ith+Containers

Cheers!

[Mirko.Binyan]

Thank you Georgi
I've seen that initial fill tutorial, but in this case we are having an object moving in the ocean.
Since we have many different cameras looking at different parts of the animation, i was thinking of caching the first frames at low res (say, cell size 0.2) , and then, at a higher resolution, cache ONLY the frames i need (cell size 0.1 or smaller).
My issue is that, if i try to cache 0->100 at grid size 0.2, and then "load & start" frame 100->200 with grid size at 0.1, the simulation seem to be starting again from scratch.
Here is a comparison of the lo res grid size 0.2 at the 99th frame, and the same fluid cached using "load & start" at the 100th frame with grid size 0.1.
you can see the water movement is present in the lower res version but not in the hi res one




Not sure if i'm doing this right. Load & Start seems to work only with same size grid

[georgi.zhekov]

Ah, the Load and Start button starts simulating from the Start Frame the same way the Start action works. So if you wish to start your sim from Frame 100, sim your low res from frame 0 to 100.
Then change your start frame to 100, change your grid resolution and then use the load and start button to load the cache.

[Mirko.Binyan]

Yep that's exactly what i did.
I'll give it a go again in a simplified scene and see if that works