Parts shifting ingame


When I play my game, random bricks start to shift randomly. They are not far away from the center, just 100 to 200 studs. It’s occuring whenever I, or other people, join the game. It does not occur when I’m editing in studio, or when I test it in studio. It started happenening a few days ago.

Please note: I’ve seen bugs like these for meshes and unions, but it never seemed to happen with parts. It’s the first time I see this happen.

These pictures should pretty much describe what is going on.
In studio:



Fix parts being offset in online mode by replicating rotations with full precision

Are the parts Anchored? Also, please leave a link to your game.


Yes, all the parts are anchored.

Game is found here:

When everyone is done looking around, any chance you could notify me again? It originally was group-only as it is being tested right now. Made it public for this purpose only.


I have experienced the same bug multiple times.

Everyting is fine in studio but when I play it in game it shifts for some weird reason.


Same thing happening here, extremely frustrating and confusing.


Online: image

Everything except the train are anchored, and there’s no weld scripts whatsoever going on in the game…


Just to be clear - this is expected in general because we currently use a slightly imperfect rotational representation for replication to conserve bandwidth. However, this hasn’t changed in years. So I’m not surprised that this happens at all - I’m surprised that the OP implies this started happening recently (there weren’t any changes in this area for quite some time now).

We’ll take a look at improving the precision here, but I want to understand if there was a regression here recently or not.

The ability to disable FallenPartsDestroyHeight

What kinda annoys me is that this apparently was a known issue for years, and that it hasn’t been fixed. I know there might be a lot of things that require work, but this seems to be a really crucial one to me.



implies that there is nothing to be fixed. It’s a known issue, but it seems Roblox has determined that it is a necessary sacrifice. Most programming decisions have trade-offs in one form or another. Though unfortunate, there’s really nothing to be done.


any update on this? We’re still experiencing this problem at Terminal Railways


Same here. I’m actually seeing the amounts of parts shifting increase while the game hasn’t increased in parts between the posts.


We haven’t worked on this since; again, my understanding is that this is a fundamental issue - it’s not a regression of any kind. Our physics system currently uses intermediate representation that is somewhat different from what is stored in the file, so this is unavoidable. Not sure when this will change…