System, method, and article of manufacture for generating a CAD model indicating an amount of material added or removed from a part to form a feature in the part

An article of manufacture, comprising:

• a computer storage medium having a computer program encoded therein for generating a CAD model indicating an amount of material added or removed from a part to form a feature in the part, the computer storage medium comprising:
• code for generating a first CAD model of the part;
• code for generating a second CAD model of the part, the second CAD model having at least one additional feature not present in the first CAD model;
• and
• code for generating a third CAD model based on the first and second CAD models indicating the amount of material either added or removed from the first CAD model to form the at least one additional feature in the second CAD model.