R15 Humanoids Gain Large Amounts of Velocity When Their HumanoidRootPart Touches the Ground

When a Humanoid in R15’s HumanoidRootPart touches the ground, it freaks out massively and slide off into the distance. No, seriously:

It slides like that until it falls off the BasePlate. Presumably it would be forever if it didn’t fall.

The model that contains these four lovely humanoids is located here:
humanoid-touching-ground-glitch.rbxm (4.2 KB)

To repo this, you can either set the HipHeight of an R15 model to 0 as I did above or you can cause a bug to occur that makes the HipHeight property not be respected. Either one will cause it to happen, which is why I explicitly say it’s a problem with it touching the ground and not a problem with a HipHeight of 0.

The expected behavior here is that it performs like the R6 example, where it just sits there sadly on the ground instead of zooming off.


For better or worse this is intentional behavior. This “my butt is caught on a corner” panic mode.

Humanoid floor sensor is currently based on a cluster of raycasts. Of course it’s possible for part the character to get caught on a corner and none of the raycasts hit it. So to avoid a player getting stuck like this, if the bottom of any of the Humanoid’s parts contacts anything, it will try to slide away from it.