I tried to manipulate a cube with the Boolean modifier. I tried to cut out an edge of the cube with a cylinder. Also, the shading result looks awful in FLAT SHADING mode, so I turned on SMOOTH SHADING.
Has anyone an idea how to achieve a better result. (I also cut out a Sphere first, this made the result less awful).
I used Blender Internal and rendered with smooth shading for smoothness. Using flat shading looks okay, except the "round" cutouts :/ Face normals are okay.
First image is smooth shading.
EDIT: User Pisurquatre suggested the EdgeSplit modifier, works perfect to me (Maybe a little tweaking here and there):