SEOUL NATIONAL UNIVERSITY

Transcription

1 Fashion Technology 6. 3D Garment CAD-2 Sungmin Kim SEOUL NATIONAL UNIVERSITY Design Process Overview Concept Design Fabric Design Scalable vector graphics Feature-based design Weave CAD 2.5D Mapping Design Process Pattern Design 2D Parametric design 3D pattern design Garment Design Body modeling 3D draping simulation 2

2 Surface Peeling Parametric Body Surface Model Parametrically Deformable Body Surface Model Cross Section Initial Solid Model Refined Model Parametric Surface 3 Surface Peeling Parametric Body Surface Model Cylindrical Approximation of Body Parts Parametric Surface Deformable Body Model 4

3 Parametric Body Surface Model Intuitive Definition of Pattern Outline using Landmarks Surface Peeling 5 Parametric Body Surface Model Garment Surface Generation Formation of mesh structure on the parametric surface model Surface Peeling 6

4 Surface Peeling Parametric Body Surface Model 2D Projection Method Basic method Project 3D elements one by one May result in irregular darts Automatic dart location According to Gaussian curvature Curvature evaluation is difficult for polyhedral surface 7 Surface Peeling Parametric Body Surface Model 2D Projection with Predefined Darts Projection Center P Mass Center C Surface Normal Direction V Target Plane Initial projection with distortion 8

5 Surface Peeling Parametric Body Surface Model Physics based projection U=5%, V=0% U=5%, V=5% Stretch tolerance along UV axis 9 Surface Peeling Body Surface Analysis Automatic Landmark Location Trimmed Data Landmark location on 3D scan data 10

6 Surface Peeling Body Surface Analysis Isoparametric 2D-3D Mapping Back Front 3D Mesh Structure Corresponding 2D Grid 2D-3D Analogy 11 Surface Peeling Body Surface Analysis 12

7 Garment Modeling Modeling of Ideal Garment Fit zone Fashion zone 13 Garment Modeling Modeling of Ideal Garment Preparation of Fit Zone From body scan data Body Scan Data Mesh Generation using Digitized Points Zebra Striping for Verification 14

8 Garment Modeling Modeling of Ideal Garment Preparation of Fit Zone Convert into deformable parametric surface Bodice Skirt Slacks 15 Garment Modeling Modeling of Ideal Garment Formation of Fashion Zone Parametric representation of fashion features 16

9 Garment Modeling Modeling of Ideal Garment Examples of Synthesized Garments 17 Garment Modeling Modeling of Ideal Garment Definition of Darts Horizontal and vertical darts can be defined along structural mesh Multiple darts can be placed on a pattern guided by curvature map 18

10 Garment Modeling Modeling of Ideal Garment Flat Pattern Development User defined darts or automatic dart generation User-defined darts Automatic Darts 19 3D Textile Design Technical Textile Interior Design Automotive Aircraft Watercraft 20

11 3D Textile Design Technical Textile 21 3D Textile Design Technical Textile Intuitive Design Optimum Marking 22

12 Interdisciplinary Nature of Textile Engineering Garment Engineering Electronics Drape Simulation Anthropometry Computer Science Electro-optics 23 FEM (Finite Element Method) Based Approach Principles Approximation of the region of interest and subdivision into a number of meshes Good for small deformation problem 24

13 Particle System Approach Principles Fabric is divided into small elements with concentrated mass Interconnected spring system 25 Particle System Approach Principles Numerical integration based on particle-spring system Gravitational Contribution d 2x dx C 2 = g damping dt Pmass dt dx dt Tensile Contribution C l l0 d 2x 2 = PQ tensile dt Pmass l0 d 2x F = ma = m 2 dt Bending & Shearing Contribution γ = POQ POQ0, l1 = OP, l2 = OQ l 1 C 1 C v1 = OP bending γ, v2 = OQ bending γ 2 2 Pmass 2 Pmass l1 Collision Detection and Resolution Particle System 26

14 Mesh Generation Triangular Mesh Subdivision of arbitrary domain into triangular elements Basic technology for drape simulation Darts and internal openings must be considered 27 Mesh Generation Automatic Mesh Generation Node connection approach Node generation» Cavendish s method (1974)» Shimada s method (1992) Element generation» Delaunay triangulation (1981)» Lee s method (1983) 28

15 Mesh Generation Automatic Mesh Generation Grid-based approach Rectangular grid and triangles Quadtree representation 29 Mesh Generation Automatic Mesh Generation Geometry decomposition approach Generates triangular or quadrilateral elements in two dimensions» Recursion based iterative approach 30

16 Collision Handling Collision Detection and Resolution The rate-determining step in fabric drape simulation Fabric-external body, fabric-fabric collision Robust collision detection and response is very important 31 Spatial Arrangement of Patterns Initial condition for physical simulation Using bounding volume defined in body model generation process 32

17 Texture Mapping Swatch vs Full-Garment Texture Versatility vs Reality 33 Simulation Results 34

18 Simulation of Detailed Features Rendered Images 35 Fitting Evaluation Visualization of Physical Properties Distribution of strain, pressure, clearance, etc. 36

19 Commercial Systems Clo3D OptiTex 37 Commercial Systems AccuMark 3D by Gerber Tuka 3D by TukaTech 38

20 Applications Magic Mirror Fashion Kiosk 39 Applications Online Dressing Room 40

21 Applications Virtual Draping Pattern Making 41 Challenges Technical Implementation of actual fabric physics in real time Robust multi-layer garment modeling Interactive fabric manipulation Educational Conventional fashion design curriculum is unsuitable for CAD Insufficient investment and lack of standardized systems Industrial Employers want to introduce 3-D systems to prepare for the future Employees are generally reluctant to new methods 42