Constraint Based On Geometric Model Solving System

In the real world,"constraints"are widely existed in all kinds of field of scientific research and living life. Computer Aided Design Technology (CAD) is a kind of technology that use computer to do modeling, modify, analyze or optimize work by adding the geometric constraint technology. In this way, not only the efficiency and the quality of product design can but significantly improved, but also the cost and the developing period of product can be decreased. The development and application level of CAD technology have already become one of the most important symbols to estimate the science and technology and the industry modernization of a country, it has given an impetus to almost every area's designing revolution. The traditional CAD technology is very effective in producing project diagram and 3D modeling. But at the design phase, we need to do some changes in order to satisfy the ultimate requirements, as this kind of"Conception"design, the rational CAD can no longer fit anymore. Parametric design (also called Dimension-Drive) is the topic which is brought up by CAD technology when applied in actual application. It not only adds the mutual charting function to CAD system, but also the automatic charting function. In that way, people try to develop the parametric CAD system with better mutual performance. In recent years, parameterization design technique has become an effective way of the product initial design, product model, revision and multi-scheme comparison and dynamical design in the design process with its powerful sketch design and revision on the graphs by size-driven. And it has got people's more and more attention. Presently, it is an important and for further researching topic of CAD application area. The special system designed by using the parametric design method can free the design staff from a lot of heavy and trivial charting work, thereby to accelerate the design speed, and reduce the memory storage. Some foreign advanced CAD systems have had the functions of parameterization to a certain degree. It has already become one of the important symbols in modern CAD systemthat has a strong parameterization design capacity.The constraint solving is the first important problem based on constraint system. But it is not come to perfection until nowadays. It mainly contains the aspects listed below:1. The design of the solving algorithm. Some common algorithms contain several classic algorithms, such as optimization algorithm and mix algorithm contains many optimization algorithms.2. Establish the problem model. We abstract the actual problems in the real world in order to get the problem model. So as to improve the solving efficiency, sometime need to reconstruct the problem model to form a highly efficient model with equal value.3. The expansion of methods class. Need to realize some diversiform mix methods, such as some method in mix calculate overall planning theory, combine elicitation method with constraint regulations methodically, in order to achieve the aim of fast solving. Further more, we need to import some knowledge of special area simultaneously to reach the method that is more efficient in solving some problems, in this way, afterwards, in the solving system, we can use different highly efficient methods to solve the different problems according to the type. Moreover, there are usually come out the condition to demand the most optimum in real world, so it must increase quantity of the most optimum methods.4. The realization of modeling language. It is a final aim of constraint system, the realization modeling language. In this way, the user need not to comprehend the specific program design language, they only need to know the much easier modeling language and then they can model the problems and solve it.5. The realization of visible interface. Presently, a lot of systems are invisible; the mutual performance with use is some kind of inconvenient. In order to realize the visible interface, from now on, need to do more work in the programming language.This thesis is sponsored by China Natural Science Foundation, aim to study and analyze the present solving methods, and link it up with the characters of geometric constraint, then try to model the system ofGeometric Constraint Solver with the parametric theory, complete the design of the whole system.First: section: The theory part:The geometric solving problems can be converted to algebraic equations solving problems; every constraint of the constraint set reflects one or more non-linear equations, all in depended geometric parameters of geometric element set form the variable set of non-linear equations. Non-linear equations can be solved by using the Newton-Raphson iteration algorithm, so, the optimum solving problem in geometric can be converted to the optimum solving problem of algebraic equation. But when the geometric constraint problem is very complicated, the amount of equation and variable in non-linear equation is large, the efficiency and stability of iteration can not fit the requirement of mutual design. What is more, when using the iteration theory to solve the equations, can not utilize the geometric information in the geometric constraint system, can not handle the lack-constraint and the over-constraint. So we are about to use the new methods below to do the geometric constraint solving problem, and deal with the lack-constraint and over-constraint in a better way.The optimum algorithms which are about to uses are:Use the particle optimum algorithm to solve the geometric constraint problem. Second section: The practical part:To begin with, with the thoroughly study of common constraint satisfying problems, to establish the problem model of constraint satisfaction, and to modeling the constraint Based on geometric model solving system, to ensure the reliability and security of the whole system, and to enhance the expansibility of system.Then, the key point of this thesis, with analyzing the code of other constraint solving model, flow the path of software engineering strictly, start with the analysis on practicability, design the system step by step, add the OO theory and UML to the design process to attain the aim of designing the Java parameter Based on constraint solving model.Above all, it is better to add various optimum algorithms Based ontactic to the prototype of solving model, and import some mix algorithm, realize the solving problem of constraint satisfaction, fulfill the expected function of system.The system is designed by using the parametric method, integrate the constraint into the programming language Java, define the graphic variable,constraint,solving system as class, the constraint Based on method use the constraint set and use the solving system to solve various constraint satisfaction problem efficiently. The system can be used in the reality, can be expanded, system also provide instructional,directive ways to describe problems, easy to maintain. System is designed by using the departure principle of question modeling and question solving, in this way, user can benefit by searching the most efficient way by testing various search attics freely, not have to worry about changing the constraint of problem; the system not only using parametric technology in the charting model, but also add the technology into the database design, First, it can make the project designer needn't consider the details and draw up the product model as soon as possible. The accurate figure is produced automatically by the system; second, it can update the design by changing some constraint parameters instead of operating the whole course of product design. The system can solve the constraint satisfaction problem quickly and appropriately, increase the efficiency of development and application.There is some work remained to improve and implement, such as variable type expansion, constraint type expansion, solving methods expansion, optimum algorithm expansion, mix algorithm imported, and so on. We will improve on those problems in our future work.