Research On Method And Technology Of Flexible Parameterization For Garment Design

GCAD (Garment computer aided design) field has attracted great interesting in recent years. Traditional GCAD was based on 2D pattern operations and so called 2D GCAD. 2D GCAD is growing into autumn. Along with 3D design technology development, 3D GCAD turns into hotspot and mainstream, but it faces many difficulties.Based on analysis of the history and problems of parameterization method, this thesis puts forward FPM( Flexible Parameterization Method), a innovative concept which is never advanced by others. FPM is a method which is based on free curve and surface as basic element, aims to satisfy constraints between basic elements, utilizes all kinds of constraint solving methods, then gains a object model expressed by non-accurate sizes. FPM is different with traditional parameterization method in three aspects including expression flexibility, constraint flexibility and solving flexibility.Based on FPM, the thesis presents GFPDM(Garment Flexible Parameterization Design Method). GFPDM is a parameterization method for garment parameterized model by all kinds of drive and united deformation operations. GFPDM includes construction, drive and united deformation for garment model. Garment model can be divided into four layers which include basic geometric layer, style layer, patch layer and pattern layer. The parameterization emphasis is put on the basic geometric layer and pattern layer. Garment model is constructed as a layered model which is expressed by non-accurate dimensions using feature information. Garment model drive changes model with multifactor by usin/g hybrid dimension input information and non-accurate constraint solving. Garment model united deformation gets a series of product based on hybrid dimension product information by deforming multi-layer functional model based on multi layer and hybrid dimension. Modeling as basis, model drive as kernel and model united deformation as trait, features including multilayer, hybrid dimension, non-accurateness run through the whole process of garment design.Advances garment component modeling technology based on hybrid dimension feature elements. Parameterized human body model provides rich semantic information of hybrid dimension feature for garment parameterization. Acquire garment feature points from body feature points and construct topology for the garment feature points, then a coarse triangle mesh will turn up, which will turn into garment mesh through surface subdivision. Utilize human feature line information to get the garment feature curve network, exert constraints on the feature curve network, then the garment feature curve frame will be formed, and then garment surface will be got by surface interpolation through 3D curves and hybrid dimension curves as surface boundary curves. Garment surface model can be produced directly by a series of operation on garment basic surface which is generated from body feature surface. These three kinds of methods each have pluses and minuses. A parameteric garment model can be got from the models modelled by the three ways through standardized treatment. The modeling way based feature lines can get parameterized garment directly, but modeling ways based on feature points and feature surfaces need further treatment.They can be used alone or can be integrated to use. After aftertreatment to the garment surface model and multi-layered integration modeling, the construction of the garment model will finish.Advances multifactor drive parameterization technology for garment parameterization. The garment model has three kinds of drive ways including size drive, sketch drive and human body drive. The human body drive also can be divided into human body's whole drive and human body's partial drive. In the way of the size drive, size value urges the relevant feature curves to deform directly. In the way of the sketch drive, after turning the 2D mutual sketch input information into the size value and constraints of the relevant curves, the goal elements can be deformed further. In the way of human body drive, human body's whole drive utilizes constraints code of curves, which encodes garment feature frame elements referred to a human body and decodes the garment feature elements referred to another human body. Human body's partial drive utilizes collision detection to adjust local part of garment mesh. To face with model dirve the garment model is also divided into two levels: The feature frame and surface. Size drive, sketch drive and human body's whole drive all act on garment feature frame directly, so the constraint validity of the garment feature frame must be maintained. Utilize graph theory, construct weight scale matrix for the garment constraint graph, after some relative treatment on the matrix, a solving route will be gained, and flexible drive of the garment model will also finish continuously. Human body's partial drive utilizes collision detection with surface subdivision to meet the precision request for garment interactive design and technology of dispart and divisional collision detection meets the speed request for garment interactive design.Advances model united deformation technology for garment parameterization. Advances model united deformation technology for garment parameterization. Utilize mesh development technology to construct map relation on hybrid dimension between patch and pattern, use pattern mapping technology to build map relation between pattern and body, then links with garment design modeling process, the design technology named united deformation technology to change garment model forwardly and conversely is formed. Based on this technology, a new grading method based on hybrid dimension is put forward. Making use of information of edge and angle of pattern polygon, two object functions are made out along with two ways including Descartes coordinate and local frame to express polygon. Through solving two ways of object functions, numerical solving robustness can be got.A 3D garment parameterized design software has been developed by exploiting the algorithms presented in this thesis and has been integrated into a garment design system named LookstailorX(LSX). LSX includes four functional modules, which includes mannequin module, garment module, pattern module, sewing and grading module. Using the LSX, many examples including the technologies for body parameterized deformation, modeling, multifactor drive and garment multi dimension united deformation for representative garment component.