Design into 3D: box: fitted
Fitted boxes are the easiest to make on a CNC --- just two pocket cuts, one rabbet, and two profile cuts.
For a round box, the needed parameters may be as simple as:
- thickness of the box bottom and lid
- thickness of the wall of the box
- width of the rabbet cut
Note that that last determines the size of the pocket of the lid, and should be adjusted by the tolerance needed to allow the lid to fit properly.