Humanoid "bounces" or floats up when standing still [only in-game, can't replicate in Studio]

Reproduction Steps
Affected Game Link:: [FASTER RESPAWN!] FLASHPOINT - Roblox

Minimal System Information:

  • Windows 10
  • AMD Ryzen 5 1600X Six-Core Processor
  • 16.0 GB RAM
  • NVIDIA GeForce GTX 1060 3GB

Expected Behavior
If everything were to work correctly, there should be no issues moving around the map and standing still.

Actual Behavior
The issue seems to happen when there is another collidable object detected underneath the one that the player is standing on. This becomes very prevalent when there are stairs or when there is a slope that goes underneath another part that a player should be able to just step off of the slope and onto the next part. As said in the post title, this problem cannot be replicated in Studio that I’ve been able to achieve.

Issue Area: Engine
Issue Type: Other
Impact: Very High
Frequency: Constantly
Date First Experienced: 2021-08-16 00:08:00 (-06:00)
A private message is associated with this bug report


It may be helpful to note as well that we started experiencing this bug around the same time that changes to raycasting were announced (see Upgraded, Improved, and Faster Raycasts). I believe it’s directly related to Humanoid floor detection, as that’s mentioned as one of the affected areas.


Additional note - while this is still happening in the regular client, the Microsoft Store client does not appear to have this behavior.


Can you please confirm whether this also happens with default Avatars?

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I wonder if this is related to welds at all, given that it seems like a similar issue to this one? Changing the size of welded Part1 causes weird collision on players standing on Part0

Sorry for the late reply, I have been away all week. This doesn’t happen with default avatars, it has something to do with the custom avatars in unison with humanoids and only shows up in-game, studio is immune to the issue.

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Another data point. I can replicate this behavior in studio. See below. This was taken right after starting up the game. Obviously a custom avatar.

To me, this looks like force is being applied to the character after movement is complete. I only get the bounce and float issues after stopping upward momentum.

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Hey all, I was wondering if any of you have adaptive timestepping enabled on your game.

PhysicsSteppingMethod? I switched mine to default, thinking that was the cause of various momentum glitches. That’s what is in my video. I switched it a while ago.

We temporarily disabled some flags, which should take care of this issue.


@TactBacon and I do not have the beta feature enabled in Studio, and naturally it’s not enabled in the live game either.

Moving forward - is this an issue that we will need to change our character implementation for, or is this a bug that will eventually be fixed by you guys? If it’s going to be a change on our end, would you mind sharing what flags were disabled so we can get a better idea of what to change?

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Problem still going on in my game.

We believe this issue was fixed with our latest release. Let us know if you are still facing any issues!


Something looks better, like the custom stands on its feet better.

Now it seems that jumping straight in the air results in a running in place when I land. Almost like the landing speed is not 0 before the state switches to Running. Walking in any direction fixes this.

I do use a custom animate script from the server(not client) . I’ll see if I can trick it to stop by throwing in some freefall code.

Edit: I figured this out. The humanoid states have changed slightly, and I adjusted my code to fit the change. Apparently, now “Landed” is immediately followed by “Running,” without triggering “Humanoid:Running.” I do not know which part changed. I suppose it’s also possible that the Running event is now called before StateChanged. Not sure if that is intentional, but I have adjusted my code to ignore the Running state in absence of the Running event connection (which is how I capture speed).

Everything is looking good on my game now!

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