Warp-knitted Seamless Garment Computer Aided Design

Computer aided design(CAD) is a procedure breaking through the traditional method to achieve the design by utilizing computer or graphic device. CAD system integrates the advantages of improving productivity, decreasing costs, elevating products quality and shortening creation period. The visual display of CAD can help to adjust design, ensure the veracity and reduce errors. The existing data can be applied repeatedly that quickens the design procedure and makes things convenient.Computer aided clothing design is the extended application of computer graphics in textile field. Traditional clothing design process needs a lot of source materials and is time-consuming, while this complicated task can be achieved by using CAD during couple hours even several minutes. The styles and patterns in the system can be reused in serialized creation. CAD gives huge influence onto clothing industry and it will play more significant positive role in the future.Different from the previous production processes, yarns – materials- style design – patterning – sewing – clothes, the manufacturing of warp-knitted seamless garments are on the foundation of modern computer processing equipment, and only dying, sizing and edge disposing are needed in the latter procedure. The advanced devices and matched CAD systems are being perfected, but there are still many things to do in the development of seamless garments design system. The typical CAD system towards seamless garments is lack. At present, the new products are less variety and just focus on sexy lingerie and pantyhose.As the disciplinary with computer graphics, computer aided clothing design gets more attention from textile and clothing fields. There are some problems needed to be solved, for example, how to build up relative models and CAD systems toward different clothing structures, design rules and wearing effects? How to create an interactive tool to achieve real-time, visual and fast design and to synchronize the 2D design display to 3D mode? How to realize the docking between design system and the process realizing system? etc. In this paper, the author focused on the implementation of the CAD system for warp-knitted seamless garments. Based on the analysis of the manufacture technology and process for these garments, parametric modeling and deformation of 3D human body, warp-knitted seamless garment pattern prototype generation and warp-knitted seamless garments virtual display would be studied.1. The parametric modeling and deformation of 3D human were achieved. The main points of this part included human model reconstruction, parametric modeling and parameter-driven deformation of human model. The human body model template was constructed by importing vertices and facets information in an OBJ model file. A parametric model was then established by extracting feature information from the template model using a method combining 3D geometry analysis and human semantic analysis. This information included the template model’s feature points and measurements. By applying a mesh deformation method, based on the Radius Basis Function interpolation, to the template model, different size human bodies were then generated according to user-specific anthropometric measurements.2. The modeling of warp-knitted seamless garment pattern prototype was realized. Based on the parametric human model and analysis of warp-knitted seamless garments structure, triangle boundary representation(B-Rep) data structure was employed to represent the triangle mesh of seamless garments. Besides, a contour model data structure of the garment mesh was set up to simply garment model processing. Horizontal plane was utilized to intersect with the triangle mesh of human body model and the convex hull of crossing points was calculated by applying the Alpha-Shape algorithm. Then a regular triangle mesh was obtained through vertex regular resampling on the convex hull’s contour and connection of the regular vertexes on the adjacent contour. With these techniques, 3D seamless garment model was obtained from 3D human model.3.3D virtual display of warp-knitted seamless garments was achieved. The vertexes of 2D garment pattern were correspondent to the vertexes of 3D garment mesh patch. 3D vertexes and corresponding triangle mesh facets were firstly collected. 3D garment prototype mesh was cut by applying techniques which was based on the cutting plane and boundary remeshing technology. Such vertexes and facets of the 3D garment patch mesh which is corresponding to the 2D pattern can be obtained. Such that, 3D patch prototypes were built up and the mapping relationship between 2D vertexes on pattern and 3D vertexes on garment patch was established by applying the 3D mesh plane parameterizing technology. Then the visual display of the warp-knitted seamless garments was realized through texture mapping technique.The three aspects above were studied closely around the point of building up the warp-knitted seamless garments CAD system. All of them were based on the forming principle and knitting structure of the warp-knitted seamless garments. The CAD system could help the designer to implement the work efficiently and it would be the powerful tool to achieve the development of warp-knitted seamless garments. And the implementation of parameterization technique establishes a foundation for the personalized customization of warp-knitted seamless garments.