Advantages:

• Predicting interaction between objects requires that the arrangement of features around the object boundary be explicit. Lists of features in order around the boundary were extensively used for this purpose. An explicit neighbourhood pointer for each feature would have been even more useful.
• Contact between objects can be easily represented by simply listing all features on the objects which touch each other.
• Hiding detail by the use of imples allows gross motions of objects to be planned without considering small details of the object shape.
• Convex subparts provide a simple and consistent method for dividing two dimensional shape into simpler shapes. In addition to providing a computationally feasible technique for acquisition of shape description from visual data, it is close enough to design techniques such as constructive solid geometry that the representation is clear to humans.
• The use of object axes as the basis for a representation can provide some degree of functional information about the object. This is evident in the ``Mechanic's Mate'' project [BA84a], where shape axes are used as cues to mechanical function; they can indicate possible rotational motion, linear motion, or direction of force application.
• Overall, the ASSF shape description method seems reasonably close to human techniques for describing shape; it is possible for a person to reconstruct the shape of an object given a description in this form.