Processing Software Based On Autocad Limited

The thesis studies the development about the FEM pre-processing software which achieves the non-slot integration between drawing software CAD and FEM pre-processing, which is based upon the AutoCAD platform. it makes enough use of the characteristic of the object-oriented character of C++ including encapsulation, inheritance and polymorphism. The basic train of thought is that extracting data from the geometry model produced by AutoCAD (two-dimension or three-dimension), then carrying out topology, transferring data to mesh generation module, achieving mesh auto-generation and illustrating the mesh, adding boundary information. This paper builds several specific classes and defines both the attribute and methods, which achieve FEM pre-processing. Chapter 1 shows the development and actuality of FEM pre-processing in advance, and emphases the development and front study on modeling and FEM mesh auto-generation technology. It also discusses the research background, main content and aim. Chapter 2 introduces the structure of AutoCAD and the development method of ObjectARX. Based upon the analysis of AutoCAD structure, discusses the common method of re-exploitation of AutoCAD, and then comes to the conclusion that the ObjectARX has the greatest prospect. The thesis analyses the frame of ObjectARX class library and method of deriving new class. The next chapter discusses the development of FEM pre-processing by C++ under ObjectARX. Commencing from the geometry model, it gives the thought on extract data from the AutoCAD database and adopts different methods for 2D and 3D models. The data are preparation of FEM meshing. The paper discusses the achievement of FEM meshing in 2D arid 3D with mapping and the generation of relational information. The specific mesh class, the element class, the node class, the load class etc. are all set up by object-orient and the result is illustrated after mesh generation. The paper develops the method of transfinite interpolation. Problems, solution and some techniques encountered in the process of meshing are also discussed in this chapter. In order to make the command performance and the data input more convenient, in chapter 4, it provides a design of the interface. The menu simplii~iing commands performance is developed. The inputting dialog box with the same style as AutoCAD II ABSTRACT is developed by making use of MFC associating with AdUi and AcUi. Chapter 5 gives several examples. Finally, conclusions and prospects are given.