I'm starting to look into physics for the first time, and since I've ventured out of the familiar territory of platformers, I've reverted back to newb status.
The first thing I tried to do is make a half-pipe shape, like a bowl, and have a ball roll along the inside. However, in the example I posted below, it doesn't roll smoothly. Its collision mask is set to circle, so I assume the problem is with the half-pipe itself.
Speaking of which, I ignored the "You should only have 8 points in the collision polygon!" rule and bumped it up to... *cough*... 19, just to see if that would make it roll smoother. It sort of did, but it's still not quite there. I assume I shouldn't be adding even more points.
You'll also notice the ball kind of goes through the half-pipe on the right side, I have no idea why that happens either.