Hello! The title almost covers it. My game has humanoid ragdolls, among other physics things. I can also go into 1/10th speed slomo at any time, using time dilation.
So my issue is that the ragdoll is on the ground crumpled up, and if it hasn’t fully gone to sleep yet, when I enter slomo, the ragdoll starts ‘unfolding’!
Visually, it looks as if the effect of gravity is weaker in slomo, since hinges that are ‘sagging’ due to gravity will ‘pop up’. Or it could be that the constraints are stronger/tighter in slomo.
My theory is that lower time deltas have lower ‘error tolerances’ in slomo. So for swing constraints at their limits due to a chain of bodies under gravitational pull, suddenly decreasing time delta now means that the constraint must be resolved more precisely, therefore ‘pulling in’ in constraints that were at the limits, and adding energy to the system.
I’ve done a lot of attempts to hackily fix or patch the behavior, with not much success. I’ve tried temporarily increasing the constraint angle limits, altering global gravity, and massaging the delta time passed to the engine. I dug into the constraint math in the engine a bit… Looks like my best bet is applying dampening of some kind. I’ve also done some searching, and usually the responses are “yeah the physics engine is buggy” or something. Someone said “don’t change dt more than 3% each time”-- I tried that, even 1%, but the constraints still ‘unfold’ and make the ragdolls move around.
Another option that COULD work is substepping, but I don’t really want to tick physics 10x in normal time all the time…
Appreciate any insights! Thanks!