A plane is segmented into a plurality of regions whose vertexes are points which include the terminals, and a route search graph is generated. The route search graph expresses a connection relationship between the plurality of regions. A line connecting two objects in a shortest distance is recorded...http://www.google.de/patents/US6219823?utm_source=gb-gplus-sharePatent US6219823 - Method and apparatus for deciding a wiring route and for detecting a critical cut
