How do I stop the liquid from disappearing when cup-shaped collision object is moving?

I am trying to have a character lift up a cup with liquid in it and drink it with the Mantaflow simulation in Blender 2.91, but when the cup is lifted, most of the liquid particles outright disappear! It’s not leaking through the cup, it’s just GONE!!!

Yes, I have raised the number of timesteps, increased the fluid resolution count, applied the scale of everything in the fluid simulation, raised the sampling substeps of the cup to 10, parented the flow geometry object to the collision object, made sure that the domain was big enough, lowered the CFL Number of the domain to 0, and even lowered and raised the time scale, but none to any avail!!!

Can somebody please help me on how to keep the liquid from disappearing when the collision cup moves!!! :scream: :scream: :scream: :scream: :scream: :scream:

Maybe follow/post here. When the a poster confirms; He does mention that he did not bake the sim, did you bake the sim?

I tried a mock-up of your situation and found the same outcome.

2.90.0

First tried a cube with the top face removed and solidify modifier,
Resolution Divisions 32

Found that the interior of the cube was not detected until the Resolution Divisions was at 128

Further, tried animating the cube in a tilting motion. with default settings and Resolution Divisions 128 the fluid spilled off the bottom of the cube.

Increased Sampling Substeps on the Effector and the Liquid to 3 and 2… The interior remained intact, but some of the liquid disappeared.

drink drink1

Yes I did bake the sim with “Modular”, and not “Replay”!
Also, I fcking knew just shortly after I made that initial post that this was going to have been a bug! :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob: :sob:

So, to try and remedy that, I am going to do something I thought up of shortly before you finished first replying. I am actually going to change the Z location of everything but the cup, and so far, everything is working as intended!

Hey, good for you.