When a Sphere Part is rolling over Unions or MeshParts with collision geometry, it will clip inside the union on edge of two vertices. This does not seem to occur with wheels (Cylinders). In a game I’m trying to develop that relies on balls and slopes, this bug causes my ball to behave erratically on slopes, making some bumps very difficult or impossible to pass over.
To get this to work, use a Part and turn it into a Sphere. Make the sphere roll using any method. For the example, I used BodyAngularVelocity. Watch the sphere roll over a few slopes created with Unions or a MeshPart and every so often, the sphere will appear to clip into the geometry. The ball appears to be trying to move along a collision vertex it was previously on before colliding with any others.
Happens often, but not every time as seen in the video, the ball rolls over three humps that are same exact copies. Ball behaves this way against other Union surfaces I’ve tested.
This bug still happens both Server and the Client sided.
I have also created a game that showcases the issue:
The game’s file here:
Collision bug.rbxl (121.9 KB)
I first noticed this bug shortly before 7/25/2019, which is when I recorded the video.
(Workaround)
A Union sphere will not have this behavior. Unions aren’t smooth and don’t roll as well as a Sphere Part, so I just made a Union sphere that’s slightly smaller than the sphere Part and welded it inside.