Camera Influences Humanoid Movement Speed

Bug Reports Engine Bugs
#1

Reproduction Steps
I cannot reproduce this bug outside of one of my games, so I have stripped all scripts out of it and can DM it upon request to any Roblox Engineer. This started happening at approximately 1PM EST, but the offending change could’ve happened before or after. I tried stripping out all scripts other than a simple debug script that tracks the distance moved per second, and it still occurs. You can find both the main game and the stripped out version linked below.

EDIT: This appears to be related to the Physics Stepping Mode. When set to Fixed, it no longer occurs. Adaptive mode causes the issues to reappear.

Reproduction Steps:

  1. Join one of the following games below.
  2. Zoom into first person as shift lock is disabled temporarily.
  3. Continue to zoom in while you walk. You will notice that you move faster than the default Humanoid WalkSpeed value of 16. I found it’s around ~137.5% of the expected value, usually about 22 studs per second.

Main Game

Game Without Scripts

Here are some videos taken by players showing the increased movement speed and odd jump behavior.

https://cdn.discordapp.com/attachments/776175409250566154/879825450573103155/Roblox_VR_2021.08.24_-_15.29.46.04.DVR_Trim.mp4
https://i.gyazo.com/31a1ec787441dc93c6ca133066d526ea.mp4

Expected Behavior
When you use Mouse Lock or continuously zoom your camera in while already in first person, it should not affect Humanoid movement.

Actual Behavior
Using Mouse Lock or continuously zooming in while in first person will increase movement speed on certain parts. These parts are anchored and have no associated velocity.

Issue Area: Engine
Issue Type: Other
Impact: High
Frequency: Constantly
Date First Experienced: 2021-08-24 13:08:00 (-04:00)
Date Last Experienced: 2021-08-24 19:08:00 (-04:00)

4 Likes
#2

I can confirm this started happening recently on my own game. My players have started reporting that using shift lock on PC can allow users to walk faster than intended.

Game Link

https://i.gyazo.com/833391240794b1778b2084d2ee364c00.mp4

3 Likes
#3

I traced it back to Workspace.PhysicsSteppingMethod being set to Adaptive. Setting it to Fixed corrected all issues on my end so far. If someone could update the title to “Adaptive Physics Stepping Mode Incorrectly Influences Humanoid Movement” I’d appreciate it.

#4

Thanks for reporting. I’ll look into this issue related to adaptive timestepping.

3 Likes
#5

I was wondering if you have any special player scripts on the humanoid. If so, can you share a stripped out place for me to debug?

2 Likes
#6

I do not, it was broken in the completely script free map. I’ll DM you a copy of the place though!

1 Like