Abstract
This thesis proposes a new method of computer input for capturing engineering workpiece profiles in the geometry creation stage of a computer-aided part programming (CAPP) environment. It represents an alternative approach differing from the (existing) input methods that rely on: a) sets of commands made at the keyboard &/or through selection of iconic / text menus which are on-screen or tablet-based; b) the building up of the profile on a piecewise line by line and arc by arc basis. This unique method employs pattern analysis /recognition techniques to capture directly the basic profile of the engineering component as it is drawn on the digitizer tablet in a flexible manner akin to draughting at the drawing board. A profile analysis algorithm deduces the topological relationship between the straight line and arc segments making up the profile. An on-line symbol recognition package is then invoked to give dimensional information to the newly-drawn profile. The entire operation of hand-drawing the profile and hand-writing the dimensions (radius, horizontal and vertical dimensions, angles between lines, etc.) reduces the geometry entry procedure to that of traditional draughting. This more flexible method imposes on the designer relatively few rules to remember and thus may present a unique solution to the description of two-and-a-half dimensioned geometrical objects such as in the initial geometry definition stage of CNC machining.