Owe ( ) Complete Study On The Algorithm Of Constrained Geometric Constraint Solving Problems

Computer Aided Design technology is a kind of technology that use hardware and software of computer to do modeling, modify, analyze or optimize work. It widely applies to all kinds of field of scientific research and living life, the application level of CAD technology has already become one of the most important symbols to estimate the science and technology and the industry modernization of a country.The development of CAD technology has gone through four significant technology innovations, the last innovation is the appearance of variable technology. Geometric constraint solving is the core of parametric technology and variable technology, it means that once the demention constraints and topological constraints are given, the system will produce the design graph automatically. At present, there are four basic approaches to geometric constraint solving: numerical approach, symbolic approach, rule-based approach and graph-based approach.At the beginning of the design, designer always adds constraints to the sketch continuously. It makes the sketch not always complete constraint,but from under constraint to over constraint. The arithmetic is always used to solve complete constraint problems. Therefore it is important to distinguish the problem is under, over or complete constraint and put under and over constraint problem to complete constraint problem before solving the problem. The arithmetic, which based on the DM decomposition of bigraph, could distinguish the problem is under, over or complete constraint and find the position, where under or over constraint happens. Based on this arithmetic, the thesis gives a method that transforms under and over constraint problems to complete constraint problems. For the under constraint problem, the thesis presents the PRI of the constraint, the means and arithmetic of adding constraints. For over constraint problem, we judge the problem coherence or not firstly, then transform it to complete constraint problem. The thesis gives some examples to validate the correctness of the arithmetic.