A DGR METHOD FOR EXTRACTING THE TOPOLOGY OF AN UPPER-HALF PROFILE OF A TURNED PART FROM CAD DATA

For a symmetrical turned part, a 2D upper-half profile is usually the input for planning functions such as turning feature extraction, process planning, and NC code generation. Current approaches to extract the topology of an upper-half profile from 2D CAD engineering drawings are heuristic and have limitations. In this paper, the drawing view cluster method and Drawing Graph Representation (DGR) method are proposed. The former has been developed to cluster front view entities into groups if the input to the activity is more than one view. Using the DGR, rules are developed to identify internal entities, external entities, types of internal profile and possible redundant entities. An example is evaluated to demonstrate the methods.