ObiRope 3.2 Crane - Prevent Rope from passing through spool

[tbookout]

Nope, there's no general, better solution for this (not just in Obi, but in the whole realm of iterative solvers, which pretty much encompasses all realtime physics solvers). You have to either increase the amount of solver iterations or cap the mass ratios.

Try an experiment: take two cubes in unity (w/ rigidbody components) and put one on top of the other. The bottom one should weight 1 kg, the top one 100 kg. This is equivalent to having ten 10kg cubes on top of the 1kg one, as 10x10 = 100. This setup will cause both cubes to immediately start jittering and go trough each other, or cause the top cube to jump off the bottom one. The highest ratio that ensures no artifacts and little/no penetration between the cubes 1/10 (a 10kg cube on top of a 1kg cube), using the default amount of iterations used by Unity (which is 6).

The above cube-based setup is also numerically equivalent to having a 10 kg load hanging from a rope made out of ten 0.1kg particles each. You could see the behaviour is roughly the same for both systems, because both PhysX and Obi have iterative solvers at their core. They both behave in similar ways, except for the jittering behavior, to which Obi is virtually immune.

Thanks for the information!

I am trying to understand the baseline rules.  In order to design scenes in Unity, that prevent the 'clipping' issue from occurring.  Without having to spend an inordinate time play-testing all the various interactions.