CylindricalConstraints Cause Humanoids to Apply Random Velocity

Bug Reports Engine Bugs
#1

Issue

When a character with a Humanoid is placed on a CylindricalConstraint joint with no network ownership, the character is applied with a small velocity in a random direction. This small velocity is powerful enough to move the player / NPC in random directions. This only happens when the humanoid rig does not have the same network ownership as the CylindricalConstraint joint.

Reproduction Steps

  1. In a studio file, create two parts.
  2. Attach a CylindricalConstraint to the two parts.
  3. Using a script, set the network ownership of one of the parts to nil. script.Parent:SetNetworkOwnership(nil).
  4. With your character or a rig with network ownership set to you, stand on one of the two parts.
  5. You will notice the character and/or rig is moving in a random direction.

This only applies to Humanoid rigs, not other parts that are owned by the Player. This leads me to believe it is a Humanoid-specific issue.

Here is a reproduction studio file:
CylindricalConstraintReproduction.rbxl (83.3 KB)

Example Videos



Expected Behavior
The character should not be applied with a random velocity.

Actual Behavior
The character is applied with a velocity in a random direction.

Workaround
For my situation, I have to have the same network ownership for the joint and player. This is not optimal, as there are other players in a session.

Issue Area: Engine
Issue Type: Physics
Impact: Low
Frequency: Often
Date First Experienced: 2023-01-29

4 Likes
#2

We’ve filed a ticket into our internal database for this issue, and we will update you when we have further information!

Thanks for the report!

4 Likes
#3

The Physics team has looked into this report, and it seems like this isn’t a physics issue but rather one that involves networking. We are still looking into how one might go about fixing or circumventing this issue, and will report back when we have more information.

Thanks for your patience!

2 Likes
#4

Upon more investigation, we’ve realized that the behavior you’re experiencing can be circumvented with the new character controller, see Releasing Character Physics Controllers for more details.