Computers are being used increasingly in the process planning function. The starting point of this function involves interpreting design data from a CAD model of the designed component. Feature-based technology is becoming an important tool for this. Automatic recognition of features and extraction of feature information from CAD data can be used to drive a process planning system. In this paper a new approach to automatic feature extraction called the 'blank-surface concave-edge' (BS-CE) approach is illustrated. This approach attempts to remove as much of the blank material within a given machine setup as possible. Hence intuitively one can say that the manufacturing cost of material removal may be minimized if this technique is employed. This feature extraction method is explained along with examples of its implementation. An analysis of alternate feature extraction results is performed and the cost of manufacture is compared to demonstrate the near optimal performance of this technique. Then a rule-bas...