The ball rolls fine, but as it gets speed, it seems to hitch/glitch on the geometry. Sometimes it can even completely stop the ball from rolling all together. In the video, each time you hear the bump sound is when it’s hitting(what I think) are the edges of the geometry, and this happens even on perfectly flat surfaces.
In Blender the geometry is perfectly smoothed, and there are no hidden polygons inside of the object, so I’m unsure why the physics are catching on what seems like the edges of polygons.
It is already is a simplified sphere collision. What I’m having issues with is; some times(randomly), the ball will hit an edge of a poly and bounce. This means unless every part of a map is flat and has no edges, the ball will randomly bounce. It goes over other edges in objects smoothly in most cases, but the random bounces are an issue.
The rolling ball instability that you’re experiencing is a common issue with physics engines. In your case, it’s probably due to the default settings of Unreal Physics Engine and your surface mesh’ quad size (they’re probably too small). You need to tune some parameters of the Physics Engine to reduce such issues. In project settings, start by lowering these values: Min Contact Offset, Max Contact Offset. You can also try increasing Contact Offset Multiplier. Note that changing these values will increase the stability but at a cost of performance!
I’m sorry that your issue has not been fixed yet. I suggest you bump this post again or post a new one here or in the forums with a “bug report” tag so that Epic staff can take a look it. You can also report this directly to Epic and provide them with materials and exact steps so that they can reproduce this on their own machines.