Can re-simulation be used to improve a loop blend?

[sam_large]

Hey, I mentioned in another sub that I'm trying to match the amount of liquid being drained/taken out of a sim with the amount of liquid being injected in.
I managed to get it fairly close but unfortunately I'm still getting a lot of turbulence on the surface of the fluid when it loops despite trying various different loop overlaps, grid blend modes and different parts of the sim.

Would setting the input controls to loop and then re-simulating offer up any better a result?

Cheers

[georgi.zhekov]

Hey,

No need for resimulation when doing a loop. The important thing when looping liquids is to have the ID particle channel exported.
You can find more about the loop options here - https://docs.chaos.com/display/PHX4M...meBendControls

When blending liquids it's important that you have a similar frames for the start and end, otherwise the blending won't be that good.

Can you show us what result you're getting?

[sam_large]

Hi Georgi,

I can confirm that the ID channel is being exported with the sim.

The sim itself is of a hot tub - multiple jets are in the backs of all the seats pushing water and foam towards the centre of the sim.
As the emitters are continually adding water to the simulation, I have a cube hidden out of sight that is non-solid and set to clear liquid inside to prevent the hot tub from filling up and overflowing.

The first photo is how the fluid looks during the majority of the sequence with the surface water rolling around with a gentle turbulence


The second is how the sim looks at the loop point - the surface becomes incredibly noisy before suddenly snapping back to being smooth like the first image


I've tried several Cache Origin points and loop lengths but due to the nature of the sim, finding something that matches closely is quite tricky. I have also tried all 3 grid blends as well as a variety of overlap lengths (5, 15, 30 frames).

Apologies for the heavy cropping but this project is still confidential.

Cheers

[georgi.zhekov]

Hmm, can you show us how it looks with the mesh preview disabled and with the particle preview enabled?

Мaybe as the particles loop, each particle from the end of the loop tries to jump very quickly to its position in the start of the loop. Since your liquid is quite turbulent, maybe this is the case.

Can you send over the scene so that we can check it out? You can submit it via the submit a request button from the top right via this link https://support.chaos.com/hc/en-us

Thanks!

[sam_large]

Sure, see attached. I'm assuming you're wanting to see the velocity of the particles?
I've included a version with and without foam just in case. Again, sorry for the heavy cropping.

I'll see what I can do about uploading a scene. Would you require the entire scene or just the sim object & cache?

Cheers

[georgi.zhekov]

It's a bit difficult to say what is going on from the screenshots, can you show us a video?

As for the scene, just the assets needed for the sim along with the caches, you can strip everything else - if the geometry is confidential maybe you can replace it with a simple one - like a box or something similar.