Something bad happened when I upgraded project from UE5EA2 to UE5. All my actor blueprints that was containing physical constraints not working anymore. Even if I am trying to create new ones they act unpredictable. Like regular constraints acts like soft ones, constrained mesh collides with base mesh even if set not to. Constrained object sticks to random rotations for some reason even if axis set to free… Still works perfectly in previous version. Did something changed in properties of constraints? Or is it just a bug that will be fixed in the next version?
Same for us, also a simple constraint that rotates on Z is wobbling and inputs that were using the angular drive motor to rotate clockwise or counter-clockwise just work clockwise. We hope that there’s a solution for this since the physic constraint are in UE5 and they are unusable at the moment.
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Have you found a way to sort this issue? I am kind of desperate. My project have so much going on with constraints. Or should we just hope it will be fixed?
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Does anyone have a solution ??.
Same goes for me and some models with physical constraints.
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Bump!
Got the same issue after moving my project to the released UE5 version. Haven’t had time to investigate the code yet, but could it have something to do with large world coordinates? 
I am not sure about that. My assets are real life sized furniture with 1,1,1 scale and still dont work. Please tell us if you manage to find a solution.
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I’m having the same problem. Brick walled the entire project. All my rigid sticks become noodles unless I tick parent dominates for every constraint, which breaks the PHATs in other ways. I would go pretty far to fix it as Chaos is very worthwhile when things aren’t broken, but I don’t even know where to start.
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constraint motors dont seem to be working at all for me
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I had to update my Loading Robot to 5.0. But the Constraints no longer worked at all.
The only solution that worked was:
I import the pincers, which open and close via constraint, into your own skeleton. It didn’t work in the same skeleton.
Also with every movement of the robot I had to wake up the physics. As soon as the robot stood still, the gripping tongs stopped working and got stuck in the air.
Maybe this approach will help some
I wonder what you mean by ‘no longer worked at all’, as in did you, by using a new skeleton, get basic constraint functionality to work or fix all the problems OP mentioned?
Asking because it would take so much time for me to retarget everything 
I meant that it does not work with the normal described migration. (Sorry for the Google translator.)
In my case, I managed to get the pliers working again using just physics.
I also read here somewhere about using a tick event to keep repositioning the parts.
Maybe not such a good solution, but it works :).
I hope there will be an improvement soon, maybe with a new version.
setting the attached static mesh to simulate physics (every tick) wakes up the motors.
angular drive motors only rotate clockwise.
the slightest outside force causes supposedly locked axes to move as if they are free.
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Any updates on this? Or reliable workarounds until they fix this? I cannot believe something this basic made it through UE5 pre-release without being tested if it works.
Alright, I am decided to code my own physics for constrained objects. With blackjack and better control. I am going to apply signed float value of impulse via interface and then apply movement and reduce it by stiffness value while looking on constraint values every tick. Or something like this. I did not find a way to make constraints work as they did in UE4 and UE5 EA versions. And I found out you need to pay to talk about it with UE developers. And I did not found issue in a current issues list.
Just tested on 5.0.2, still not working properly 
Guess we gotta report the thing for it to get fixed?
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Ok so apparently the default setting for chaos physics iterations is very low and not fit for a physics-centric project. Changing that solved almost everything for me and I feel very stupid rn.
Sadly this also means the performance gain I saw over Physx is fake.
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Do you mind saying what you did to solve it please? How did you change the physics iterations? Thanks.
Thanks guys for the tip! I went to “Edit->Project Settings”, searched for “Iterations” (it’s under Chaos Physics, Solver Options) and doubled it from 8 to 16 which fixed the physics issues in my game.
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@Manim8 this. Only 16 tho?? I had to bump it all the way to like 200 and I’m still not entirely happy with the accuracy 
I also added an Execute Console Command blueprint node on that calls “p.Chaos.Solver.SleepEnabled 0” on BeginPlay. That seemed to fix my other physics problems. (I’m not even sure Iterations needed to be increased.)
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