ZOZO's Contact Solver for physics-based simulations

Is your comment here to refute a claim you saw somewhere, or to simply point this out? I wouldn’t expect this to be real-time, given the complexity, nor do I believe it needs to be in order to be useful.

Re: ZOZO's Contact Solver for physics-based simulations

#6

Post by erwincoumans » Thu, Oct 30, 2025, 4:36 PM UTC

totallymike wrote: post #5

ivanjermakov wrote: post #3

Not realtime, seconds-minutes per frame.

Is your comment here to refute a claim you saw somewhere, or to simply point this out? I wouldn’t expect this to be real-time, given the complexity, nor do I believe it needs to be in order to be useful.

It is good to point it out it is for offline simulations. There is some related recent work, Offset Geometric Contact that is suitable for interactive use: https://ankachan.github.io/Projects/OGC/index.html

Re: ZOZO's Contact Solver for physics-based simulations

#7

Post by SecretDreams » Thu, Oct 30, 2025, 4:37 PM UTC

Contact is a hard problem to solve and there's some tangential softwares that do it well within the FEA space. I'd be curious to know how this does with materials/geometries of vastly different stiffnessess and if it produces realistic reaction/contact forces (one cheap way to manage contact is to jack up the contact stiffness, which will prevent penetration, but drive some unrealistic forces at those interfaces).

Re: ZOZO's Contact Solver for physics-based simulations

#8

Post by suioir » Thu, Oct 30, 2025, 4:52 PM UTC

What value do all the emojis provide?

Re: ZOZO's Contact Solver for physics-based simulations

#9

Post by zokier » Thu, Oct 30, 2025, 4:54 PM UTC

If I'm understanding correctly, the same approach was implemented also in IPC Toolkit here: https://github.com/ipc-sim/ipc-toolkit/pull/148

Re: ZOZO's Contact Solver for physics-based simulations

#10

Post by embedding-shape » Thu, Oct 30, 2025, 5:05 PM UTC

totallymike wrote: post #5

ivanjermakov wrote: post #3

Not realtime, seconds-minutes per frame.

Is your comment here to refute a claim you saw somewhere, or to simply point this out? I wouldn’t expect this to be real-time, given the complexity, nor do I believe it needs to be in order to be useful.

Also assumed by default we were talking about real-time, but then I saw Python/juPyter and a rendered videos, got a bit confused, then came across "46.4s/frame" for one of the examples and finally registered it wasn't about real-time.

I agree it doesn't have to be real-time to be valid, I think my mindset just goes to physics in video games which are usually real-time when I see contact solvers or most other things related to simulations.