This problem has been occuring for many people I know. It started happening at least 2 weeks ago.
Constraints seem to have gotten screwed up in an unexplained physics update. Sometimes the trucks can just completely disappear and fling themselves upon getting into the truck, or sometimes need to be driven at a certain speed to be flung, or a constraint needs to be moved to trigger the flinging. A person I know who has created a constrainted chassis has had the truck fling whenever the truck leans too much in one direction and had the same disappearing behavior. In any case, this needs to be fixed and I’m wondering if anyone has experienced the same thing. Thanks.
Here’s a demonstration of the new behavior. Notice how the truck slides to the left before disappearing.(warning: volume may be loud)
This is somewhat a big problem for me & my players. I have a train that is supposed to go around the map & it just vanishes because of this bug.
I’ve also noticed that when this bug happens, sounds just randomly stop working. Resulting in players having to rejoin to get sounds working again.
I was experimenting a few days ago for the cause of it, thinking it was a problem on my end and all I could figure out is that small part sizes can cause this to happen? (but I’m not entirely sure if thats the cause, it looks like physics get overloaded…)
This also causes other physics based objects to just “delete” themselves for no reason. I think this issue started appearing sometime during November.
Reproduction File where other physics related objects disappear: Physics Bug.rbxl (64.1 KB)
THIS. This glitch is what happens in my game every once in a while. Back in 2021, the game would disconnect me, but now I re-appear, followed by having desynced controls due to changed network ownership for a few seconds, and then things return to normal…Or at least, what’s considered “normal” in the game.
This seems to be happening on many other games, this issue has occurred many times in my game but I thought it might’ve just been my computer or something and didn’t think much of it until I also started seeing it happen to other people and I also have experienced it on other games like ERLC (Emergency Response Liberty County), the only fix to this is just to rejoin the game
If there is a nan value in any of the velocity parameters , with MaxForce/MaxTorque/etc values being extremely high (or inf, in my case.) then this issue will happen constantly without fail. I believe this didn’t even cause parts to delete themselves in the past.
Here is a script to reproduce this issue.
local OriginPosition = script.Parent.Position
local LookAt = script.Parent.Position
local MyVelocity = CFrame.new(OriginPosition,LookAt).LookVector
local bv = Instance.new("BodyVelocity")
bv.Parent = script.Parent
bv.MaxForce = Vector3.new(math.huge,math.huge,math.huge)
bv.Velocity = MyVelocity
print(MyVelocity) -- What is the velocity result?
game.Debris:AddItem(bv,.2)
I kind of resolved this issue by checking if the origin position is identical to the “lookat” position, then apply a tiny offset, like .001 so I don’t get nan values.
i think this may also caused other physics objects to just disappear as seen in my reproduction file. (or is another separate issue)
I noticed this behavior didn’t carry over to constraint builds with lower torque. I constantly use high or inf torque/accel on my builds just for the sake of stability. Those builds never had this issue before though. I even lowered the torque on some of my builds to only about 5000 and they still created the same issue. Happened less often, but still not good.
We’re investigating this currently, could you please provide an rbxl with the trucks that experience this crash?
UPDATE: This was indeed caused by a change in the physics engine made late last year. A fix for these types of issues was enabled about a month ago, please feel free to send me a DM if you notice similar issues!
