Velocity tries to snap to 0, 0, 0 if close to it

I am working on a spaceship combat game, the ships use physics and the thrusters increase velocity in their given direction, in UE4 this worked fine, but since upgraded to UE5, when the ship is stationary with velocity 0, 0, 0 some force tries to keep it there, if I try to thrust the ship forwards it takes considerable force to get the ship moving, if it gets to 1,0,0 velocity then i release the thrust it will snap back to 0, it needs to get past maybe 5 velocity on any axis then there is no issues and the velocity can freely and accurately be changed.

Hi CodeNil,

I just came across a post that seems related to your problem.

Were you using Chaos Physics in your UE4 project? I think you used to be able to choose between Chaos and PhysX (with PhysX being the default) Now Chaos is the default, which might explain any differences.

Please take a look at his sample project and let me know what you think!

Welcome to the forums.

This issue sounds like it’s unrelated to my problem, it sounds more like a physics object sleep sensitivity issue, try turning the sensitivity modifier to 0 to disable sleeping on your object and see if you still get the same problem.

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I believe this is indeed related to the physics sleeping, I have it printing on tick if the physics mesh is awake, and it goes to false after a couple seconds, then when I try to thrust to move it it rapidly toggles between true and false, I have tried setting “Sleep Family” to Custom and “Custom Sleep Threshold Multiplier” to 0 but that has not solved this.
I believe I was using PhysX when it was in UE4 too yes.

Thank you.

Thanks @Neros . Since Chaos is ‘newish’ both issues might just be some rough edges. (or fundamental problems lol) It may be a good path forward to submit a bug report . Creating an example project in 4.27 might be helpful in proving that it’s definitely a regression. At very least it’s another step towards getting these problems on the engine devs radar.

I have managed to find a way to reliably reproduce this on a new project and submitted a bug report, thank you for your assistance.
Seems to be when a physics object has very large mass and has small impulses added to it, it forces it to go to sleep and stop moving.

So all we can do now is wait? I gave up on three projects because of physics, one of them being a space game with a spaceship just like yours.

Does that mean UE5 has no useable physics but still they go around making updates that fix minor issues?

This is huge, the new engine does not support physics. Any real news on it? I know the usual answer is to keep working on 4.27 but I don’t want that, the new engine changed its physics engine so I feel like I have to jump on it.

How are they transferring Fortnite to UE5 without physics? How are all those people making games without physics? This is really frustrating.