A while ago I had an idea of a man made planet that consist of a thick, incredibly strong, outer crust, and at the core there is an antigravity/antimatter device that also produces consistent heat and light constantly. The crust is just at the point where the antigravity is about equal to earths gravity, and the people would live on the inside of the crust. It would have large shallow oceans, and a few continents. The flora and fauna is pretty standard, but because the entire planet is man made, there wouldn't be any large predators. Probably no mountains either, because the layer of liveable antigravity is small.
My question again is what would the weather be like in this sort of situation? There is no day/night heat change to cause pressure differences and therefore wind, and there's no rotation of the planet to cause wind or coriolis effect.
This idea isn't very well thought out yet, but I wondered if anyone had any thoughts on it.