How to do the physics of buoyancy in Isaac Sim?

[w.correa02]

Isaac Sim Version
[ ] 5.0.0

Operating System
[ ] Windows 11

GPU Information

• Driver Version:

Topic Description

Hi everyone — I’ve progressed well on the robotics/control side, but I’m stuck on buoyancy. To isolate the problem, I’m trying the simplest possible case: make a 1×1×1 cube float. After ~2 weeks of reading docs, forum posts, and experiments (plus some ChatGPT help 😅), I still can’t get it to float.

I suspect my Python script is correct (code link below), and that I’m likely missing a critical setup step on the cube (e.g., physics/rigid body/collider/material/water setup). If someone who has successfully implemented buoyancy in Isaac 5.0 on Windows could point out what I’m overlooking, I’d be very grateful.

• Code link: GitHub - WandersondaSC/Isaac_Sim_5.0_Floating_in_water: Project that makes a cube float on water in Isaac Sim 5.0

• What I expected: cube floating stably at the water surface

• What happens: cube sinks / doesn’t respond to buoyancy forces

• What I’ve tried: enabling rigid body & collider, checking extension load (omni.physx), different mass/density, different backends, timeline run/pause, etc.

• GPU & driver: (add model + driver version)

Thanks in advance for any guidance!

[w.correa02]

Well, after 2 days of working straight, I "activated Hyperfocus" and managed to get it working.

[PeterNV]

Thanks for the update! Let us know if your need further help.