SOLVING GEOMETRIC CONSTRAINT SYSTEMS - I - A GLOBAL PROPAGATION APPROACH

We describe a geometric constraint solving method/system that takes th e declarative description of geometric diagrams or engineering drawing s as input and outputs a sequence of steps to construct the diagram wi th ruler and compass if it succeeds. We extend the local propagation t o a global one. Like the local propagation, the global propagation tri es to determine the position of a geometric object from the set of geo metric objects whose positions are already known. However, our global propagation uses not only the constraints involving this object but al so implicit information derived from other constraints. The algorithm can be used to build intelligent CAD and interactive computer graphic systems. (C) 1998 Elsevier Science Ltd. All rights reserved.