how to correct topology after boolean operation? So I have used the boolean operation to create a spherical hole inside a cube and was wondering how I could correct the topology. The result of this was: 
So I was wondering how I can edit the topology so I can use subsurface modifier or if it is better if I Use a different method to create the hole. If I should recreate it a different way than what would be a good way keeping in mind that this is from a cube.
Thanks!
First triangulate the model.
After that, add a subdivison modifier, with simple and one with Catmull-Clark selected. Then do loopcuts, where you want to have sharp edges. Slide the loopcuts till the edges, but not on them, just a little bit before.
You have to play a little bit with the strengt of the modfiere.