Hey everyone,

My overall goal is to simulate liquid poured into a glass with ice cubes inside, with the ice cubes floating.

Everything works pretty normally until I enable feedback forces:

• Normal: https://gfycat.com/LameCarelessIzuthrush [gfycat.com]
  
• With feedback: https://gfycat.com/FlashySolidFreshwatereel [gfycat.com]
  

There's a ton of particle loss. For these sims, particle separation is 0.004, grid scale is 2, feedback force is 1, and max FLIP substeps is 10.

The best I got was to maintain volume with 1.75 grid scale, but with overreacting ice cubes: https://gfycat.com/MiserlyEmbarrassedAfricanbushviper [gfycat.com]
I've attached the Houdini file for this below.

Anything related to this problem would be helpful. Why is there particle loss, even without reseeding or with many substeps (I've tried using 20)? Is there a problem with how I'm using feedback? Why does changing grid size cause volume to increase or decrease?

Thanks!

Funny, I have encountered the exact same problem. Sorry that I am not able to provide you any answers, but I will monitor the responses to this thread closely.

Do you use RBD Hero Object for the ice cubes? RBD packed object have a lot of problems with FLIPs.

Sorry but I don't have Houdini in this machine and I don't open your scene.

http://forums.odforce.net/topic/30618-drastic-flip-volume-change-with-feedback-on-rigid-bodies/ [forums.odforce.net]

Thank you very much! I owe you for all the time you've saved me.

I thought I could make it work with an accurate scene scale, but this still looks realistic. For others, sepu had bumped up my cup size from 25cm to 750cm and lowered feedback scale from 1 to 0.75.

I did use RBD Hero objects. I wasn't aware of that problem with packed objects, so thank you!

I tried only lowering the feedback scale [gfycat.com], but it seems like the root cause was the scene scale.

Again, thank you!

Edit: Actually, the sloshing around in the cup gives away the scene scale, but I imagine playing with the forces and velocity smoothing will fix that.