CAD Graphic File Data Acquisition And Visualization

With the long-term development of China's manufacturing industry,the completion and commissioning of high-speed rail,large aircraft,aircraft carriers and other countries have fully demonstrated that China's manufacturing technology has made great progress,and some industries are even at the world's leading level.Mechanical manufacturing is inseparable from design drawings and corresponding data files.With the continuous use of computer technology in mechanical manufacturing,the high-speed computing performance of computers can accelerate the full cycle of products in all stages of design,production and testing.CAD graphic files are common documents for machine manufacturing and have become standard documents for modern manufacturing.This type of file contains almost all the data information of the product,including geometric dimensions,geometric tolerances,manufacturing materials,manufacturing processes,color layout,applications,etc.In the whole process of mechanical manufacturing,CAD graphic files are the standard and the core,and all manufacturing behaviors are carried out and unfolded around the graphic files.The CAD graphic files introduced in this paper play an irreplaceable and indispensable role in the whole design and manufacturing process,which runs through the entire design and manufacturing process.From the design and simulation of components(the appropriate file format should be determined according to the subsequent production and testing in the design process),to the processing and manufacturing of components(production and processing according to geometric dimensions in the production process),to the inspection and evaluation of components(testing the process measures whether the product is qualified according to the geometrical tolerance.The CAD graphics link all the links together to form a complete industrial chain.Designing a complete set of industrial software is very complicated.This article only introduces the main problems that need to be studied and solved in the design of industrial software in the relevant aspects of CAD graphics files.It includes the following three problems: 1.reading general 2D and 3D graphic files;2.processing the read data accordingly;3.3D modeling to realize visualization of graphic data.In response to the above three questions,this paper has made specific research and analysis.The main work is as follows:(1)According to a series of 2D and 3D CAD graphic files well known in the world,the file structure and composition of the most representative three graphic files(DXF format file,STL format file)are analyzed.And according to the structure of the graphic file,a method of reading the file and obtaining the data is proposed.(2)The Voronoi diagram and the Delaunay triangulation are studied,and the high-speed and effective triangular patching of the 3D geometric entity is realized according to the Delaunay triangulation;On the basis of the mapping method,combined with the advantages of the mapping method,this paper proposes a cutting method to obtain a geometric mesh quickly and efficiently;Using the principle of matrix transformation,the coordinates of the graph are quickly switched between the two-dimensional coordinate system and the three-dimensional coordinate system;Analyze the transformation relationship between model transformations,and combine them with various model transformations to realize arbitrary transformation of the model.(3)In order to realize visualization,various types of illumination models have been studied,including ambient light,diffuse reflection light,and specular reflection light;The study of the transparent model and the addition of a light attenuation factor;The ray tracing and bidirectional reflection distribution functions are analyzed,visualization based on the above theory.