Research And Implement On The Technologies Of Region Searching And Pattern Sewing Based On GCAD

It is an inevitable trend for GCAD system to convert from 2D to 3D due to 3D computer technology's maturity and the necessity of customized garment. Although related research has vigorously expanded, a lot of work needs to do to achieve the practical level. In this thesis, we researched the technologies of cutting region searching and 2D pattern sewing, and also elaborated the essential process about the prototype of 3D garment flattened to cuttable and sewable 2D patterns as well as 2D patterns sewed to 3D garment for demonstrating garment modeling effect.3D cutting of garment is completely based on the manikin; hence garment made by patterns which were obtained from 3D cutting conforms to the human body. Automatic region searching is a key problem of 3D cutting. In chapter 2, started from surface trimming, things about automatical region searching are defined with details. In addition, a searching algorithm for normal cutting region is presented, which considers searching speed and accuracy. A new searching algorithm for cutting region with Darts or Super-lines is proposed, which solved the problem about region searching with special cutting lines in garment or joy design. Finally, several examples are gived to compare the efficiency and the precision of the algorithm.2D pattern pretreatment is the foundation of pattern sewing. In chapter 3, surface flattening algorithms have been introduced briefly. Based on the mass-spring model and geometrical flattening algorithm, surface mapping from 3D to 2D are implemented. Also method of building boundary of patterns is presented. Algorithm gets the information of boundary lines from 3D cutting line and creates the boundary lines using cubic B-spline. In the end, method of getting sewing information is depicted. Boundary lines are discretized into point set in the precondition of searching common cutting line.2D pattern sewing is an available method for inspection the garment design effect. In chapter 4, regular Delaunay triangulation methods are introduced and compared through several instances. In view of the mesh is not top-quality after re-triangulated, edge exchange and edge energy optimization as the mesh optimization methods are proposed. Meantime, mesh vertices are mapped from 2D to 3D by using barycenter coordinates and dispersive patterns are sewed to manikin by using information of shared boundary line among meshes. The entire process flow is simple, effective and easy to implement. It also guarantees the accuracy of sewing result.