I don't see any contoured surface in the picture - it looks like a prismatic part.
There are many ways to cut the green face. If the part and blank are selected in the workpiece, the easiet is probably to create a floor_wall operation, and pick the green face as floor. The system should find all the walls and material.
I can't promise a way to mill the sharp corners ;*)
Mark Rief
Retired Siemens
