Contents
1 Modeling Bodies…………………………………………………………………………….. 1
1.1 Introduction……………………………………………………………………………. 1
1.2 Geometric Modeling………………………………………………………………… 2
1.2.1 Basic Geometric Deformations………………………………………. 3
1.2.2 Free Form Deformation…………………………………………………. 4
1.3 Physically Based Modeling………………………………………………………. 12
1.4 Anatomic and Anthropometric Body Modeling Techniques…………… 13
1.5 Data Acquisition……………………………………………………………………… 24
1.5.1 Data Acquisition and Reconstruction Pipeline………………….. 25
1.5.2 Data Resolution and Data Format…………………………………… 27
1.5.3 Scan Data Based Modeling Approaches………………………….. 28
References………………………………………………………………………………………. 29
2 Character Based Adaptation…………………………………………………………… 31
2.1 Introduction……………………………………………………………………………. 31
2.1.1 Character Animation…………………………………………………….. 31
2.2 Previous Works……………………………………………………………………….. 33
2.3 A Footskate Removal Method for Simplified Characters………………. 35
2.3.1 Feet Motion Analysis……………………………………………………. 36
2.4 Root Translation Correction……………………………………………………… 38
2.4.1 Horizontal Correction……………………………………………………. 38
2.4.2 Vertical Correction……………………………………………………….. 40
2.5 Character Movements Adaptation……………………………………………… 42
2.5.1 Introduction…………………………………………………………………. 42
2.5.2 Skeleton Design……………………………………………………………. 44
2.5.3 Arms Adaptation…………………………………………………………… 49
2.5.4 Legs Adaptation……………………………………………………………. 53
2.5.5 General Purpose Collisions Removal………………………………. 55
2.5.6 Balance Correction……………………………………………………….. 55
References………………………………………………………………………………………. 68
3 Cloth Modeling and Simulation………………………………………………………. 71
3.1 A Brief History on Garment Simulation……………………………………… 71
3.2 Measuring Physical Parameters…………………………………………………. 75
3.2.1 Introduction…………………………………………………………………. 75
3.2.2 The Concept of Fabric Hand………………………………………….. 75
3.2.3 Fabric Drape………………………………………………………………… 89
3.2.4 Mechanical and Physical Fabric Properties in Virtual
Simulation Systems………………………………………………………. 91
3.3 Physical Simulation of Cloth…………………………………………………….. 92
3.3.1 Introduction…………………………………………………………………. 92
3.3.2 Physical Properties of Cloth Materials…………………………….. 93
3.3.3 Simulation Models……………………………………………………….. 95
3.3.4 A Simple Method for Accurate Simulation of Nonlinear
Cloth Materials…………………………………………………………….. 99
3.3.5 Numerical Integration…………………………………………………… 103
3.3.6 Collision Processing……………………………………………………… 106
3.3.7 Real-Time Garment Animation………………………………………. 112
3.4 Touching Virtual Textiles…………………………………………………………. 115
3.4.1 Haptic Interaction with Virtual Textiles:
The Problems to Solve…………………………………………………… 116
3.4.2 The Sense of Touch………………………………………………………. 118
3.4.3 Rendering Touch Signals……………………………………………….. 120
3.4.4 Haptic Interfaces………………………………………………………….. 123
3.4.5 The EU Project HAPTEX: Concepts and Solutions………….. 128
References………………………………………………………………………………………. 132
4 Designing and Animating Patterns and Clothes………………………………. 139
4.1 Introduction……………………………………………………………………………. 139
4.2 Pattern Design………………………………………………………………………… 140
4.2.1 Digitalization……………………………………………………………….. 140
4.2.2 Import from CAD Software…………………………………………… 140
4.2.3 Extraction of the Outer Shell Pattern Pieces…………………….. 141
4.3 Pattern Placement……………………………………………………………………. 142
4.4 Seaming…………………………………………………………………………………. 143
4.5 Fabric Properties……………………………………………………………………… 143
4.6 Garment Fitting………………………………………………………………………. 144
4.7 Comparison of Real and Virtual Fitting Processes……………………….. 145
4.7.1 Physical Precision of the Simulation Result…………………….. 147
4.8 The Making of the Award Winning Film: High Fashion
in Equations……………………………………………………………………………. 149
4.8.1 Introduction…………………………………………………………………. 149
4.8.2 Robert Piguet……………………………………………………………….. 150
4.8.3 Inspiration……………………………………………………………………. 151
4.8.4 Design and Implementation…………………………………………… 152
4.8.5 Result………………………………………………………………………….. 158
References………………………………………………………………………………………. 159
5 Virtual Prototyping and Collaboration in the Clothing Industry……… 161
5.1 Introduction……………………………………………………………………………. 161
5.2 The New Market Trend……………………………………………………………. 163
5.3 Virtual Prototyping of Garments……………………………………………….. 163
5.3.1 Current Design and Manufacturing Paradigms…………………. 164
5.3.2 Current Online Garment Customization………………………….. 166
5.3.3 MIRALab’s Virtual Try On……………………………………………. 167
5.4 Collaboration in Virtual Clothing………………………………………………. 171
5.4.1 Distinction Between PDM and PLM………………………………. 171
5.4.2 PDM/PLM in the Apparel Industry: Current
Solutions/Examples and Their Benefits……………………………. 173
5.5 Future Challenge: Co-design…………………………………………………….. 173
5.6 Towards a Co-design Virtual Garments Platform…………………………. 174
5.6.1 Related Work……………………………………………………………….. 175
5.6.2 Design Considerations…………………………………………………… 177
5.6.3 Communication Architecture…………………………………………. 177
5.6.4 User Membership Management……………………………………… 179
5.6.5 Content Transmission Scheme……………………………………….. 180
5.6.6 Event Management……………………………………………………….. 181
5.6.7 Proposed Architecture…………………………………………………… 181
5.6.8 Overall Architecture……………………………………………………… 182
References………………………………………………………………………………………. 185
Preface
This book contains the research on modeling bodies, cloth and character based adaptation performed during the last 3 years at MIRALab at the University of Geneva. More than ten researchers have worked together in order to reach a truly 3D Virtual Try On. What we mean by Virtual Try On is the possibility of anyone to give dimensions on her predefined body and obtain her own sized shape body, select a 3D cloth and see oneself animated in Real-Time, walking along a catwalk. Some systems exist today but are unable to adapt to body dimensions, have no real-time animation of body and clothes. A truly system on the web of Virtual Try On does not exist so far. This book is an attempt to explain how to build a 3D Virtual Try On system which is now very much in demand in the clothing industry.
To describe this work, the book is divided into five chapters. The first chapter contains a brief historical background of general deformation methods. It ends with a section on the 3D human body scanner systems that are used both for rapid prototyping and statistical analyses of the human body size variations.
Chapter 2 reviews techniques to efficiently and accurately animate virtual humans. The techniques described here enable to tailor the animation to specific subjects, including their shape, and weight characteristics. These animations can then be used to produce virtual catwalks, which in turn can be used as a basis for a Virtual Try On application.
In Chapter 3, methods for measuring the physical parameters of textile materials are described. The core of the chapter is given by the section on the physical simulation of cloth. The addressed topics range from the generalities of mechanical simulation and state-of-the-art techniques to the description of a simple method for accurate simulation of nonlinear cloth materials, covering also numerical integration, collision handling and real-time animation issues. The chapter ends with a section on the haptic interaction with virtual textiles which describes the problems to solve when touching cloth-like deformable objects in a virtual reality environment. It includes a case study detailing the research and development of a prototype interface designed for the haptic simulation of cloth.
The next chapter describes how to design and prototype garments before the manufacturing process. Designers create 3D clothes based on 2D patterns which are either imported from CAD systems or created manually. This process is presented on a case study showing the making of the award winning film “High Fashion in Equations”.
The last chapter deals with real life applications as virtual garment prototyping. A discussion addresses current design and manufacturing paradigms and the online customization of garment. A practical example of such online customization is demonstrated by means of MIRALab’s Virtual Try On. The chapter finishes with a technical proposal of a virtual garment platform enabling co-design, ranging from low-level communication to higher level user-management.
List of Figures
Fig. 1.1 Design of super-quadric primitive by spherical
cartesian product………………………………………………………………….. 4
Fig. 1.2 Visual results of global deformations
on the leftmost object……………………………………………………………. 5
Fig. 1.3 (a) FFD based deformation, bending a cube.
(b) Underlying objects………………………………………………………….. 5
Fig. 1.4 A realistic animation of a human leg with NFFD……………………… 6
Fig. 1.5 (a) A cross section of the original surface with control points.
(b) Refined version of A. (c) Modified surface (Courtesy
of David R. Forsey)………………………………………………………………. 7
Fig. 1.6 The complex surface is created by the refinement method
(Courtesy of David R. Forsey)………………………………………………….. 7
Fig. 1.7 Transformation from lower dimension to upper one
and then back to lower one with deformation………………………….. 8
Fig. 1.8 (a) From ellipse to cat. (b) Deformation tool inside and outside
the model (Courtesy of Philippe Decaudin)…………………………….. 8
Fig. 1.9 Deformation around the constraint and the resulting effect
on a grid……………………………………………………………………………… 9
Fig. 1.10 Deforming constrained regions on the body model…………………… 9
Fig. 1.11 Real-time anthropometric body deformation……………………………. 10
Fig. 1.12 Wires deformation application for head model and inverse
kinematics (Courtesy of Karan Singh and Eugene Fiume,
Autodesk Inc)………………………………………………………………………. 11
Fig. 1.13 Sweep surface generated by moving ellipsoids
(Hyun et al. 2003)………………………………………………………………… 11
Fig. 1.14 (a) Template musculature mapped on the leg model.
(b) Skin with/without deformation…………………………………………. 12
Fig. 1.15 Combination of skeleton and muscle images to construct
a 3D model………………………………………………………………………….. 13
Fig. 1.16 Realistic musculoskeletal model
(Courtesy of Joseph M. Teran)……………………………………………….. 14
Fig. 1.17 Dynamic skinning effects
(Courtesy of Caroline Larboulette)…………………………………………. 14
Fig. 1.18 Human body modeling techniques………………………………………….. 15
Fig. 1.19 Several anthropometric human body measurements…………………. 16
Fig. 1.20 Human factory system architecture………………………………………… 16
Fig. 1.21 Joints for the hand and the full body and the sample
implementation of JLD operators in action……………………………… 17
Fig. 1.22 Muscle abstraction through FFD
(Courtesy of Richard Parent)…………………………………………………. 17
Fig. 1.23 Dynamic muscle effect based on FFD
(Courtesy of Richard Parent)…………………………………………………. 18
Fig. 1.24 FFD application on body segment
(Courtesy of Norman I. Badler)……………………………………………… 19
Fig. 1.25 Slice collisions around the joint region…………………………………… 20
Fig. 1.26 Sample model hierarchy and coordinate frames of nodes………….. 20
Fig. 1.27 Anchored skin to muscle with rest and extend postures…………….. 21
Fig. 1.28 Parametric deformed cylinder for muscle modeling…………………. 21
Fig. 1.29 Muscle deformation (Courtesy of Richard Parent)……………………. 22
Fig. 1.30 Muscle modeling on upper arm
(Courtesy of Richard Parent)…………………………………………………. 23
Fig. 1.31 Variational and anthropometric modeling
(Courtesy of Doug DeCarlo and ACM)…………………………………… 23
Fig. 1.32 Offset determination and triangulation method………………………… 25
Fig. 1.33 Camera and laser placement………………………………………………….. 26
Fig. 1.34 Different scan frames……………………………………………………………. 26
Fig. 1.35 Top view of scan heads with multiple cameras
and laser lights…………………………………………………………………….. 26
Fig. 1.36 Combined slides…………………………………………………………………… 27
Fig. 1.37 Human body scanning system (Courtesy of MIRAlab Research
Laboratory, University of Geneva)…………………………………………. 28
Fig. 1.38 Template based body modeling………………………………………………. 29