Physics issues since Update 571, only on Live Servers


Since the release of the new update 571 for studio & live games, one especially critical issue has appeared, that makes my game absolutely and utterly unplayable. Frontline: Karelia, whose players count usually revolves around 80-120 players has tanked and now has only 27 players.

Your character can rotate his shoulders/head up & down to aim the weapon currently being held. This has always used to work smoothly and flawlessly, but since 571, suddenly whenever the joint’s CFrame properties are updated, it seems to me what I could only describe as an opposite reaction force happening: The weapon is brought up, and as a result the character is pushed backward. The weapon is brought back down and the character is pushed forward. Worse, whenever the player enters first person view, the code which handles the weapon aiming & updating of the CFrame applies lateral changes, which in turn causes a bunch of sideway forces.

This to me seems absolutely unintended as this change only ever happens in live instances and never in studio. I’ve tried finding workarounds, by changing the player’s mass, fiddling with RootPrioritiy, setting all of the parts of the weapon to massless, but to no avail.
As a result, players are unable to aim properly, to set-up machine gun position, to move & crawl properly, to sneak behind other players, and as a result to even just play the game and enjoy the experience.

Here’s a few GIFs, taken with Gyazo, demonstrating the issue:

Aiming in a live instance: (WRONG)

Aiming in studio: (EXPECTED)

Entering a crawl in live instance: (WRONG)

Entering a crawl in studio: (EXPECTED)

I checked the version number of both the game & the studio and both are the same. There is something incredibly frustrating with this, as I am absolutely clueless on what may have caused the issue and as such I can not try to pinpoint a workaround. I’ve read through the recent patch-notes on the DevHub, looking through all of the recent improvements & fixes to make sure something somewhat related to physics has not been changed, and indeed none of them explicitly describe an obvious change to physics solving.

One of my developer has fiddled with the “PhysicsSteppingMethod” property in the Workspace, and the game right now has it set to “Fixed”.

However, switching to “Adaptative” in Studio seems to reproduce the issue, wherein the character starts gliding sideways & forward/backward when moving the gun & entering crawl. Most likely, either the game has the PhysicsSteppingMethod reset/defaulting to Adaptative in Live game no matter what is selected in studio, or Fixed/Default values have been entirely overriden by mistake after the recent 571 update.

There are a lot of other developers who are experiencing a somewhat related issue, which only happens during live instances & since 571. Some of them report issues with animation, other meshes, other collision group, but what I can reliably say is that the issue does not exist in studio unless switching to Adaptative PhysicsSteppingMethod, but no matter the method selected in live game, the method always seem to be or act Adaptative.

This is Critical & we need an urgent fix or revert until the issue has been addressed !
Game: [ALPHA 1.3.2D] Frontline: Karelia 40 - 44 - Roblox


Yeah whatever happened in this update is messing everyone up.
I hope they fix it real quick so you have your player count back up.


Reposting this recording along with info from the original post in case the og post was somehow overlooked:

video recorded @ 120fps

in my case:
occurs on R15, not R6
consistently replicatable when using a script that modifies the CFrame of an R15’s LowerTorso CFrame/Motor6D
does not occur in when playing in Roblox Windows store app
using default Animate script for the R15 clip (no animations are being overridden)
only happens in live servers, and not in studio
noticable at lower fps, worsens at high fps
worsens when humanoid is walking on a slope

1 Like

A similar-sounding issue was reported before, and that had a staff member stating that some fixes had been applied. Is this issue this occurring?

Fortunately it looks like the issue has been fixed thanks to this recent change !

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.