Dear All, Does any one know how can i get implementation of the following algorithm for the concave polygon(with holes) operations (union, intersection, difference). Polygon Comparison using a Graph Representation by Kevin Weiler - 1980. Thanks in advance Faisal

Thinking back about 15 years... IIRC, Graphics Principles and Practice by Foley, van Dam, et al. link has a section, and very possibly in-book code for this algorithm. That's the one where the intersecting edges are doubled up (with opposite orientation) to create individual polygons, right?