关键词: 全成形毛衫, 花式结构, 几何模型, 网格模型, 三维结构仿真, 服装虚拟展示

Abstract:

Objective Whole garment formation technology has been an attention hotspot in the sweater industry because of the integral manufacturing and wear comfort of the product. With the fast development of the computer-aided design technology, fashion computer aided drafting(CAD) software has made the design and manufacture of textiles easier and more accurate. In order to represent the whole garment more realistically, more quickly and more conveniently using knitwear CAD software, this research focuses on the three-dimensional simulation of whole garment with fancy structures.
Method Loop models were established based on the classical Pierce loop model for knitted fabrics. By drawing loop grids and comparing the offset of loop grid mass point between undeformed loops and transformed loops, the transformed loop value of physical fabrics with fancy structures for whole garment was represented. Coordinates of control points of loops were calculated by combining the offset value of transformed loops with theory of vectors transformation in the two-dimensional space. Three-dimensional simulation of fancy structure was achieved by using JavaScript programming language.
Results Characteristics of all fancy structures used for whole garment was analyzed. The geometric model and grid-based model of plain stitch loop were built separately as shown in Fig. 1 and 2, and those of closed tuck loop were built separately as illustrated in Fig. 3 and 4. The deformation process of loops is showed in Fig. 5. The deformation was represented by loop grids according to the methods explained in Fig.6. The loop grid was transformed firstly, leading to the transformed of loops. In order to create the three-dimensional effect of the fabric, loop grids shown in Fig. 7 were drawn based on loop height and width, and the offset value of grid mass points was measured by comparing with the position of grid mass points of undeformed loop grid. Then, the average proportion of grid mass points was calculated and listed in Tab. 1. The control point coordinates of every transformed loop listed in Tab. 2 were calculated by the relation between offset proportion and control points as illustrated in Fig. 9. The transformation matrix was obtained, and related formulas of the calculation were established. The simulation tool was created by using Visual Studio Code software, as well as three-dimensional graphics engine library based on WebGL. The loop path was created by calling function CatmullRomCurve3 in the graphics engine library, which uses Catmull-Rom interpolation algorithm for path generation. The loops were created by calling function TubeBufferGeometry. Finally, three-dimensional simulation of whole garment with fancy structures with features such as fabric narrowing, fabric widening and partial knitting was completed, and it was illustrated in Fig. 10.
Conclusion Three-dimensional simulation of multiple types of fancy structures and whole garments could be completed by the methods introduced in this paper. The models of fancy structures are realistic with clear structures, with the correct relationship between loops. The simulated fancy structures could be applied in three-dimensional virtual display of whole garment. In the future, three-dimensional simulation of other forms of whole garment could be achieved using the methods.

Key words: whole garment, fancy structure, geometric model, grid-based model, three-dimensional structural simulation, garment virtual display