Abstract: The present invention is a system that takes a drawing definition produced by a CAD/CAM system 10 and produces a debugged part program. The drawing definition is used to produce a sequence of processes which will produce the part. The drawing definition is a list of the surfaces which create the part. The list is scanned by a process planner 14 and a list of primitive shapes and transition points in each shape is created. The transition points are used to create a process tree defining regions for machining. The tree is populated with region boundaries that are used to designate machining operations. The boundaries are then used to select particular processes based on the shape to be machined during the operation by traversing a shape tree looking for a match. The process selection also specifies tools, feeds and speeds necessary for rough machining the part.