Softbody-based Crawling

[wenhao_zheng]

Hi,

It's not possible to rely solely on friction to grab objects this way. The reason is that friction calculations are a simplified model (Coulomb with a 4-sided friction cone) that does not take into account contact manifold area, does not behave equally in all directions, does not consider torsional friction, and overall prioritizes performance over correctness.

Furthermore both Unity's rigidbody engine an Obi are iterative solvers, which do not guarantee convergence. So it's not possible to do this using rigidbodies either.

To my knowledge, there's no game-ready/realtime physics engine that can ensure perfect grabbing behavior based solely on contact friction. Grabbing objects in games typically involves some kind of specialized joint or constraint that latches the object to the manipulator grabbing it. Even simple cases like a character standing on a moving platform are generally achieved by parenting transforms, instead of relying on friction.

In Obi's case, you can use pin constraints or dynamic attachments + collision callbacks to achieve something similar.

kind regards

Thanks!
By the way, I saw a component called Obi Stitcher, and there is also a constraint called Stitcher in Ik Solver.
But I didn't see this concept in the documentation. Is it deprecated?