[Game-breaking] Corescript ragdoll system sets avatar limb positions to Vector3(nan,nan,nan) if triggered while an animation is playing

Bug Reports Engine Bugs
#1

Reproduction Steps

Currently, as of 10/24/22, if a player gets ragdolled by Roblox’s built-in ragdoll system (can be found in the corescripts) while an animation with Action priority is running in a loop, various limbs of the player’s avatar are positioned to Vector3(nan,nan,nan). This causes all sorts of wild behaviors with the avatar & the humanoid, consistently breaking game logic.

Steps to reproduce:

  1. Open the attached reproduction file
  2. Enable the “China” test player profile under Test → Player:
    image
  3. Run a playsolo session
  4. Observe the “action” priority animation being ran on the avatar
  5. Reset the avatar (via the escape menu)
  6. Observe that the avatar has had various limbs set to Vector3(nan,nan,nan) and is rapidly blinking, among other odd behaviors.

NaNRagdollIssue.rbxl (36.7 KB)

My production game, Super Skyward Towers has recently started getting odd behaviors around the same time this reported bug started occurring. If players are ragdolled, the run animation now continues playing even if they aren’t walking. This was not happening before. It’s possible some engine change is the root cause of this bug.

EDIT : This is critical. This is literally breaking our production game. If a player is in a fall-scream state in our game and they get ragdolled, the nan position bug occurs. This was not happening before. It’s definitely related to an engine change.

Expected Behavior
It is expected that the corescript ragdoll system would ragdoll the player, regardless of what animations are running.

Actual Behavior
The corescript ragdoll system positions various avatar limbs to Vector3(nan,nan,nan) when triggered if there are “action” priority animations being ran on the avatar. It’s worth noting, both animations & the ragdoll system from the corescripts both modify the joints / motor6Ds internally, so there might be some correlation there.

Workaround
None

Issue Area: Engine
Issue Type: Other
Impact: High
Frequency: Constantly
Date First Experienced: 2022-10-24 00:10:00 (-04:00)

6 Likes
#2

Urgent bump, this is breaking our game in production. A recent engine change is causing this issue.

1 Like
#3

Can replicate, in our game if a player dies they get “flinched”, just a little fling that lasts for 0.18 seconds, (bodyvelocity) however if the player DIES while an animation is playing, they get fling in the void. (This is due to the animation still playing and ragdolls interfering.)

#4

This is still happening as of 10/25/22.

#5

Since I assume you took your own copy of the scripts, can you try commenting out the call to ApplyJointVelocities.

I suspect that function may have been broken during an internal animation runtime rewrite.

1 Like
#6

I’ll give this a try! Will post results here.

#7

Hey @ContextLost! Commenting out ApplyJointVelocities fixed the issue! I’ll leave it commented out as a temporary patch. Hopefully you folks fix the underlying engine issue :slight_smile:

#8

FYI, ApplyJointVelocities has been broken for a while now. I had to fake it.

1 Like