1. Overview of 3D CAD technology
1. 1 Market demand analysis of 3D CAD technology
1. 1. 1 international manufacturing informatization trend
At present, in the field of international manufacturing, manufacturing technology is developing from traditional manufacturing methods to advanced manufacturing technologies, and manufacturing informatization has become an important trend of manufacturing development.
The core of digital construction of manufacturing enterprises is the digital design and manufacture of products and the integration of related digital technologies. Three-dimensional digital design technology is gradually becoming the focus of enterprise design and application, and it is also a necessary tool for enterprises to deepen their application. As an important part of information technology, CAD combines the high-speed mass data storage and processing of computers with people's comprehensive analysis and creative thinking ability, and plays an important role in accelerating engineering and product development, shortening the design and manufacturing cycle, improving quality, reducing costs, and enhancing the market competitiveness and innovation ability of enterprises. Whether it is military or civil industry, whether it is construction industry or manufacturing and processing industry, whether it is machinery, electronics, textile products, or culture and sports, the production of film and television advertisements is inseparable from three-dimensional digital design technology. Three-dimensional digital design technology is an important technical foundation of enterprise informatization, and it is also a ticket for enterprises to enter the international market.
1. 1.2 Great advantages of 3D CAD technology
The application of 3D CAD technology can greatly improve the design efficiency and quality of products and projects, improve working conditions and enhance the market competitiveness of products and projects. Foreign statistics show that the application of three-dimensional CAD design technology can reduce the engineering design cost 13 ~ 30%. It can shorten the time from design to production by 30-60%; Improve product quality by 5 ~ 15 times; Increase the breadth and depth of analysis problems by 3 ~ 35 times; Product productivity increased by 40-70%: input equipment productivity increased by 2-3 times; The processing procedures are reduced by 30-60%; Reduce labor costs by 5-20%. With the research, development and wide application of three-dimensional digital design technology, it can promote the development of China's software industry, especially the application software industry. This will not only accelerate the technological transformation of traditional industries and products, but also promote the rapid development of traditional disciplines. The resulting direct and indirect economic benefits are enormous, and its social benefits are immeasurable.
1. 1.3 New opportunities for the development of 3D CAD technology in China.
In China, the three-dimensional digital design market is almost monopolized by the products of foreign companies. Some enterprises spend a lot of foreign exchange to introduce foreign three-dimensional digital design systems, but due to many factors such as the mastery of technology and the gap of industry standards, they are either idle or inefficient, which makes it difficult to popularize and apply them. Under the new situation of respecting intellectual property rights and joining WTO, domestic enterprises are increasingly calling for domestic software with appropriate functions and moderate prices.
In recent years, the development of computer-centered related technical fields, such as network technology, e-commerce and database, has had a profound impact on CAD technology. New manufacturing methods, such as decentralized networked manufacturing and customer-oriented mass customization, also put forward new requirements for CAD system, which makes the design and manufacturing resources of industrial products more widely used. Through WEB technology and ASP technology, the collaboration between industrial product design and manufacturing is realized, and the software service system of the whole industry is established. In addition, due to the individualization of industry-oriented CAD systems, the competitiveness of foreign technologies is relatively weak, which is a good opportunity to shorten the gap in China's CAD field. With the leap-forward development of digitalization, networking and integration in the whole life cycle of enterprise products, CAD itself will also face an all-round upgrade. Therefore, China's CAD software technology has great development space.
1.2 development of 3d CAD technology in China.
The Great Development of CAD Technology in China
CAD technology has a history of more than 30 years since its birth. It has experienced two-dimensional drawing, wireframe modeling, surface modeling, solid modeling, feature modeling and other important development stages. , but also accompanied by the integration of parameterization, variation, size drive and other technologies. After more than 30 years' efforts, CAD technology has become more and more mature in the basic theory and software industry, and many excellent CAD systems have emerged, such as Proffingineer, UGll, IDEAS CATM, Solidworks, SolidEdse and so on. It has been widely used in aerospace, machinery and electronics, construction engineering, textile and clothing and other manufacturing industries, greatly improving the product design level of manufacturing industry.
1.2.2 Overview of major national 3D CAD projects
According to the national demand and the development trend of software technology/industry, the research, development and application of 3D CAD technology and product innovative design system are listed as major software projects in the 863 Program. Focusing on operating system, database management system and major application software, we will strive to master the strategic, cutting-edge and forward-looking key technologies related to system software, greatly increase the ownership of independent intellectual property rights through innovation, improve China's independent software system, and support the national economic and social informationization and national information security construction.
During the Tenth Five-Year Plan period, the three-dimensional digital design system oriented to industry and design process has been widely concerned. The application practice proves that its design efficiency and intelligence are incomparable with general CAD software. The three major 3D CAD projects of "863 Plan" have made great progress and great comprehensive benefits, and basically reached the level of commercialization.
2. The development and application status of 3D CAD software for clothing.
2. 1 Development Status of 3D CAD for Clothing
With the development of computer technology and social economy in China, people have higher and higher requirements for the quality, fit and personalization of clothing. The existing two-dimensional garment CAD technology can no longer meet the CAD application requirements of textile and garment industry, and garment CAD urgently needs to develop from the current graphic design to three-dimensional design. Therefore, in recent years, theoretical research and practical application have been carried out in three-dimensional clothing CAD and virtual reality clothing design at home and abroad.
According to Autodesk's statistics on the overall application of CAD, at present, about 30% of users in the world use 3D CAD for product design, and the remaining 70% still use 2D CAD for design. In fact, 3D CAD has been widely used in the world, but in the field of clothing, the development and application of 3D CAD is relatively backward. This is because clothing is not like solid products in mechanical and electronic industries. Its texture is elastic and will change with different external conditions, so the simulation is very difficult. In particular, to realize the transformation from 2D to 3D in garment CAD, it is necessary to solve the technical problems such as fabric texture and dynamic expression, 3D reconstruction, vivid and flexible surface modeling and so on. These problems lead to a long development cycle and great technical difficulty in 3D garment CAD.
Clothing 3D CAD is different from 2D CAD. It is an interactive 3D design based on 3D anthropometric data model, and then generates 2D clothing samples. It mainly solves the problems such as the establishment and partial modification of three-dimensional human body size model, the prototype design of three-dimensional clothing, the covering and shading of three-dimensional clothing, the display of three-dimensional clothing effect, especially the dynamic display, and the reversible conversion between three-dimensional clothing and 2D clothing.
The basis of 3D garment CAD is 3D anthropometry. At present, the three-dimensional anthropometric system has been commercialized and the technology is mature abroad. Among them, France, the United States, Japan and other countries can complete the measurement of three-dimensional human body data in 40 milliseconds, 10 seconds and 1.8 seconds respectively by using the principle of natural light grating. The commonly used three-dimensional anthropometry technology in the world is generally non-contact, which captures the image of the human body formed by the light projected on the human body surface through photosensitive equipment, and then describes the three-dimensional characteristics of the human body through computer image processing. Compared with traditional measurement technology, three-dimensional human body measurement system has the advantages of short measurement time and large amount of data obtained.
Clothing size based on mass production of clothing can not accurately reflect the body characteristics of the crowd. At present, the establishment of human database of various groups of people is being carried out at home and abroad. Through the targeted three-dimensional anthropometry of a large number of people with different skin colors, different regions, different ages and different heights, the data of various human bodies are collected and a database is established to provide basic data for formulating clothing specifications and sizes.
Three-dimensional anthropometry generates a virtual three-dimensional human body by obtaining key geometric parameters of the human body, establishes static and dynamic human body models, and forms a set of system with virtual human body display and dynamic simulation functions. On this basis, 3D clothing CAD generates the three-dimensional effect of clothing cloth, vividly displays the 3D color image of wearing effect on the screen, and expands the three-dimensional design into a plane piece approximately.
Three-dimensional design based on two-dimensional CAD is gradually developing in the direction of intelligence, physical analysis and dynamic simulation, and parametric design is developing in the direction of variable and super-variable; 3D wireframe modeling, surface modeling and solid modeling are developing to feature modeling and semantic feature modeling. The research and application of component development technology also provides a foundation for the opening of CAD system and the realization of free assembly of functions.
Transforming a three-dimensional garment design model into a two-dimensional planar garment piece involves the technology of developing a complex spatial curved surface into a plane, which is determined by the elasticity and flatness of garment materials and the difficulty of three-dimensional garment CAD. Scholars at home and abroad have done a lot of research work and obtained many methods of complex surface expansion, and many methods have also been applied in practice.
2.2 3D clothing CAD application status
At present, there are two main types of 3D garment CAD applications in foreign markets:
First, it is used for tailoring: according to the measurement of body parameters of specific customers and their specific requirements for clothing styles (such as looseness, length, width and other preferences), clothing design is carried out, and then corresponding flat clothing samples are generated. This kind of products can be remotely controlled through the Internet, among which the systems in the United States, Britain, France, Germany, Japan and Switzerland are more advanced.
Second, it is used to simulate the fitting system: through the three-dimensional measurement of the customer's body shape, interactive clothing design is carried out, and then the corresponding plane clothing sample clothes are generated. This application can also be realized by remote control of e-commerce through the Internet. For example, Land'send Company in the United States can build a virtual model of the customer's body on the Internet, and try on the clothes introduced by the company through the simple operation of the customer, and carry out three-dimensional interactive design until the customer is satisfied.
At present, some foreign products can basically realize three-dimensional clothing wearing, collocation design and modification, reflect the animation effect of clothing wearing comfort, simulate the three-dimensional drape effect of different fabrics, and realize 360-degree rotation and other functions. Among them, the 3D garment CAD software developed by the United States, Japan, Switzerland and other countries is relatively advanced, such as the CONCEPT 3D garment design system introduced by CDI Company of the United States, the 3D system of Lectra Company of France, the AM-EE-SW 3D system of Gerber Company of the United States, the 3D system of PAD Company of Canada, and the 3D system of Toyo Textile Company of Japan.
China is a big country in clothing, but it started late in the advanced technology of clothing. Although the research in this field in China has made initial progress and achieved 3D-like CAD design, there is still a big gap with the foreign technical level. At present, only Hong Kong Science and Technology, Beijing Changfeng Science and Technology Company, Beijing Institute of Fashion Technology, Sun Yat-sen University, Hangzhou Echo Company, Shenzhen Ying Ning Company, etc. In recent years, the garment three-dimensional covering model fitting system has been developed, and only some software has entered the commercialization stage.
3. Development trend of garment CAD technology
3. 1 CAD technology is facing a new trend of deepening application.
In recent years, CAD technology has achieved rapid development, but at the same time, it has exposed some problems in development, which are mainly manifested in over-emphasizing the development of unit technology, over-emphasizing the universality of the system, ignoring the product life cycle design oriented to the design process, ignoring the application of network technology, ignoring the development of database and feature library, and so on. In order to solve these problems, combined with the latest development of manufacturing information technology, the developers of CAD technology put forward a three-dimensional digital design system for industry and process (product life cycle). This system has become a hot spot of research and development at home and abroad in recent years, and is regarded as the only way to deepen the application and leapfrog development of CAD technology.
3.2 Integration of industry-oriented and design processes
The original self-contained CAD system and its supporting technologies have been and are being integrated into CIMS (Computer Integrated Manufacturing System), and interfaces and integrations have been established with CAM, MIS, PDM and ERP. It is another development trend of clothing CAD system.
3.3 clothing design networking based on network technology
With the rapid development of Internet in recent years, it is expected that online fashion design will gradually become the mainstream. Under the increasingly specialized and global production and operation mode, the enterprise's network-based CAD system can realize data sharing and standardization, and the concurrent design of products will also provide support for efficient and fast CAD systems. In order to effectively improve the market scale and product profits, the integration of clothing CAD and e-commerce is also an inevitable trend. An Internet-based remote data transmission and monitoring system for clothing enterprises will soon come out, which also provides effective technical support for the networking of clothing design and the informationization of clothing enterprises.
3.4 Fashion design automation based on virtual reality design technology
In recent years, the United States, France, Germany, Japan and Switzerland have also carried out the research and development of virtual clothing CAD, and started the application research of ultra-dimensional clothing design. The so-called super-dimensional fashion design is super-dimensional visual design, which requires fashion designers to consider not only design elements such as one-dimensional lines, two-dimensional curved surfaces, three-dimensional shapes, four-dimensional time and five-dimensional meanings, but also many factors such as human psychology, human vision, human aesthetics and human taste, and pay attention to the application of environmental psychology and decorative psychology. Fashion designers use virtual reality design technology to design clothes in a computer-displayed virtual reality environment through vision, hearing and touch.
This virtual clothing CAD technology uses network transmission and virtual reality design technology to enable designers to design clothing in virtual environment. In addition to the computer, the required hardware devices include digital human body sensors such as data gloves and data coats, stereoscopic display devices such as helmet monitors and shutter glasses, and other related supporting devices. This virtual reality design technology realizes the automation of fashion design.
3.5 Intelligent Clothing Design Based on Intelligent Support
At present, all clothing CAD products are complicated, and it takes a long time for professional and technical personnel to fully master the application, which is also an important reason for the slow popularization of CAD products. Therefore, looking forward to the future, it is expected that the future clothing CAD products will develop in the direction of high intelligence, and provide intelligent support for designers by establishing more clothing model modules and design guides. These intelligent supports include self-learning, self-organization, self-adaptation, self-correction, parallel search, associative memory, pattern recognition, automatic knowledge acquisition and other intelligent technologies. Gradually transition to an operating software as simple and easy to learn as WINDOWS. In the future, with the development of hardware technology, it will become a reality to become a highly intelligent "fashion design fool" by embedding software in anthropometric instruments.
4. The idea of developing garment 3D CAD engineering.
According to China's garment CAD technology and its industrialization development level, combined with the development status of China's 3D CAD technology and its technical support for industry CAD, we put forward the idea of developing garment 3D CAD engineering, aiming at accelerating the development of garment 3D CAD engineering which conforms to national conditions, takes garment 3D CAD as the core and faces the whole life cycle of industries and products on the basis of existing garment CAD technology. This project includes three-dimensional anthropometry technology, three-dimensional clothing CAD design software, clothing CAM system and clothing design technology in virtual reality environment.