@raigan Right, yes that makes sense. Thanks for the great information.

Dirk Gregorius said:
SPRING_ZETA = 0.0; → This does not make any sense

Okay so my assumption is wrong that the box would oscillate forever if zeta is 0. I was trying to use that as a way to verify the correctness of the solver. It is behaving correctly though if I compare zeta to 1. When zeta is less…

@Dirk Gregorius @Aressera  Thank you for the help that all makes sense. I was also reading Allen Chou's Contact Constraints article and he touches on this topic.

He says “You might notice that this clamping method is not perfect. We can end up with clamping the magnitude of total tangential imp…

I just implemented a very rough version of warm starting (using absolute contact positions) - just as a test. The box stack is stable now. But I'm still interested in knowing whether it was supposed to be stable even without warm starting, to exclude the possibility I have bugs.

EDIT: a 15-box stack…