Subject name
Department of Clothing Engineering, Department of Clothing Industry, Famous Fashion Institute
Name of class students
The urgent problems to be solved are:
Interface between style design module and structure design module. The style design and structure design of almost all existing clothing CAD systems are relatively out of touch, and the renderings completed in the style design module can only be used for reference by structure designers, and the structure design is carried out entirely by looking at pictures and people's experience. Therefore, the interface between renderings and patterns is developed, and the garment CAD system is integrated internally, so that the output of the former becomes the input of the latter, that is, the garment renderings will be (or partially) automatically transformed into plane patterns or three-dimensional garment structures.
The development of CAD technology has a history of more than 30 years. In the development of CAD, new technologies and algorithms are constantly emerging, mainly in the research and development of modeling, data management and standardization technology. The development and application of CAD system in China has achieved initial results, but there are still some problems.
The development of CAD technology is closely related to the practical application and demand of the industry. With the need of practical application, some new computer application technologies and some new algorithms appear and develop in CAD, which are mainly manifested in: the research and development of modeling technology; Research and development of data management technology; Research and development of standardization technology.
Modeling technology is the core technology of CAD. The research, development and application of modeling technology represent the research, development and application of CAD technology.
Two-dimensional modeling is the initial CAD technology to solve two-dimensional drawing problems, and later developed into three-dimensional geometric modeling technology. Three-dimensional geometric modeling is divided into wireframe modeling, surface modeling and solid modeling. Wireframe modeling is to construct three-dimensional objects with lines, and its main algorithm is that the fitting and expression of spatial free curves are relatively simple. Surface modeling is to construct three-dimensional objects from surfaces, and its main algorithm is the generation algorithm of free-form surfaces or sculpture surfaces, which is more complicated. Entity modeling is to form a real entity, and the algorithm is complex. With the development of geometric modeling technology and the need of practical application, parametric and variable modeling technology appeared in the late 1980 s.
Feature modeling is a new development of CAD modeling method. Feature modeling is to better express the complete function and production management information of products, and to serve the establishment of integrated information model of products. Features include the specific geometric shape, topological relationship, typical functions, drawing representation, manufacturing process and tolerance requirements of the product. The reference of features directly reflects the design intention, making the established product model easier for people to understand and organize production.
Product integration modeling is the concept of relational product model oriented to product life cycle. This concept solves the problem of information sharing in design, manufacturing, inspection and assembly, describes various attributes and relationships of products in the whole process of conceptual design, assembly design and part design, and realizes the product integrated modeling technology of internal description information (such as product design, planning, processing and inspection) and external process information (such as the environment on which internal description information depends), which is still under study.
In the research and application of CAD technology, data management technology is another important technology, especially in CAD integrated system.
Before 1970s, data was mainly managed by file system. By 1968, IBM developed the first generation database management system-hierarchical database management system IMS；; From 65438 to 0969, CODASYL, an American database research group, published the DBTG report and established the second generation database management system-network database management system. By 1970s, the research and development of the third generation database technology focused on the relational database technology. In the late 1970s and early 1980s, a commercialized relational database management system appeared, which is still very popular. In the late 1980s, the research of the fourth generation database technology began, that is, the research and development of engineering database and object-oriented database.
In recent years, China has made some achievements in the development and application of CAD system. A two-dimensional CAD commercial software market has initially formed in China, and some enterprises have introduced CAD systems and achieved certain benefits. But compared with foreign countries, the gap is still very big.
1. At present, China's CAD system is only used as a drawing tool, lacking the guidance of design methods and design theories.
2. The 3D CAD system in China is still immature, so it must be developed quickly.
The real solution to the product design problem is the 3D CAD system, but at present, the 3D CAD system independently developed in China has not really formed commercial software.
3. There is little development and innovation of CAD technology in China, and there are many imitations.
Without innovation, there is no competitiveness, and only imitation can not develop competitive products. This problem exists from two-dimensional CAD in China to three-dimensional CAD currently developed.
4. The development of CAD software in China lacks theoretical research and algorithm research.
CAD technology is a comprehensive high-tech, involving a wide range and complexity, with rapid technological changes and fierce competition. As far as modeling technology is concerned, it will involve many modeling theories and algorithms, which are developed to meet the needs of users. Every theory and algorithm used in CAD system will produce new CAD software. For example, the famous CSG, B-rep, NURBS and so on. However, China's CAD software developers lack this research, and have not seen the famous theories and algorithms used in CAD for many years. You can only quote others, and of course you can only follow others.
5. The information integration technology is backward.
6. The format and standardization of data exchange in 6.CAD are backward.
teacher
completion date