Handbook of Virtual Humans

Handbook of Virtual Humans......Page 4
Contents......Page 8
Preface......Page 17
List of Contributors......Page 18
List of Figures......Page 19
List of Tables......Page 27
1.1 Why Virtual Humans?......Page 28
1.2.1 Early Models......Page 30
1.2.2 Short Films and Demos......Page 32
1.2.3 The Evolution towards Real-Time......Page 34
1.3.2 Virtual Presenters for TV and the Web......Page 35
1.3.3 Virtual Assistants for Training in Case of Emergency......Page 36
1.3.4 Virtual Ancient People in Inhabited Virtual Cultural Heritage......Page 38
1.3.5 Virtual Audience for Treatment of Social Phobia......Page 39
1.3.6 Virtual Mannequins for Clothing......Page 40
1.3.7 Virtual Workers in Industrial Applications......Page 41
1.3.8 Virtual Actors in Computer-Generated Movies......Page 43
1.3.9 Virtual Characters in Video Games......Page 45
1.4.2 A Flexible Motion Control......Page 47
1.4.3 A High-Level Behavior......Page 48
1.4.5 A Realistic Appearance......Page 49
1.4.6 Interacting with the Virtual World......Page 50
1.5 Conclusion......Page 51
2.1 Introduction......Page 53
2.2.1 Facial Modeling Review and Analysis......Page 54
2.2.2 Generic Human Face Structure......Page 58
2.2.3 Photo-Cloning......Page 59
2.2.4 Feature Location and Shape Extraction......Page 60
2.2.5 Shape Modification......Page 65
2.2.6 Texture Mapping......Page 66
2.2.8 Validation of the Face Cloning Results......Page 68
2.3.1 Motion Capture for Facial Animation......Page 73
2.3.2 MPEG-4-Based Face Capture......Page 74
2.3.3 Generation of Static Expressions or Key-Frames......Page 76
2.3.4 Analysis of Facial Capture Data to Improve Facial Animation......Page 77
3.1 Introduction......Page 79
3.2.2 Simple Volumetric Primitives......Page 80
3.2.3 Multi-Layered Models......Page 81
3.3.1 3-D Scanners......Page 82
3.3.2 Finding Structure in Scattered 3-D Data......Page 83
3.3.3 Conforming Animatable Models to 3-D Scanned Data......Page 84
3.3.4 Photo-Based Shape Reconstruction......Page 85
3.4 Dynamic Motion Capture......Page 87
3.4.1 Early Motion Analysis......Page 88
3.4.2 Electro-Magnetic and Optical Motion Capture Systems......Page 89
3.4.3 Video-Based Motion Capture......Page 91
3.5.1 State Vector......Page 94
3.5.3 Optimization Framework......Page 95
3.5.4 Implementation and Results......Page 97
3.6 Conclusion......Page 98
4.1 Introduction......Page 102
4.2.1 Anthropometry......Page 104
4.2.2 Anthropometric Human Models in CG......Page 108
4.2.3 Motivating Applications......Page 111
4.2.4 Challenging Problems......Page 112
4.3 Our Approaches to Anthropometric Models......Page 113
4.3.2 Data Acquisition......Page 114
4.3.3 Pre-Processing......Page 116
4.3.4 Interpolator Construction......Page 121
4.3.5 Results and Implementation......Page 123
4.4 Conclusion......Page 125
5.1 Introduction......Page 126
5.2.1 The Levels of Abstraction of the Musculo-Skeletal System......Page 128
5.2.2 Techniques for the Animation and the Control of the Multi-Body System......Page 130
5.2.3 What Is Motion?......Page 131
5.2.4 Background to Inverse Kinematics......Page 134
5.2.5 Review of Inverse Kinematics Resolution Methods......Page 136
5.2.6 Other Issues in the Production of 3-D Character Animation......Page 139
5.3.1 Background to Numeric IK......Page 140
5.3.2 Handling Two Conflicting Constraints......Page 142
5.4 MPL-IK Results......Page 143
5.5 Conclusion......Page 144
6.1 Introduction......Page 146
6.2.2 Muscles......Page 147
6.2.3 Bone......Page 148
6.3.2 FACS (Facial Action Coding System)......Page 149
6.4.2 Parametric Model......Page 150
6.4.3 Muscle-Based Models......Page 151
6.4.4 Finite Element Method......Page 155
6.4.6 MPEG-4-Based Facial Animation......Page 156
6.5 Tongue, Wrinkles and Other Features......Page 163
6.7 Conclusion......Page 164
7.1.1 Rigid Deformations......Page 167
7.1.3 Skinning......Page 168
7.1.4 Contour Deformation......Page 169
7.1.5 Deformations by Example......Page 171
7.2 Volumetric Models......Page 172
7.2.1 Implicit Surfaces......Page 173
7.2.2 Collision Models......Page 174
7.3.2 Muscle Layer......Page 175
7.3.4 Skin Layer......Page 182
7.4 Conclusion......Page 185
7.4.2 Depth of Simulation......Page 186
7.4.3 Future Research Directions......Page 187
8.1 Introduction......Page 188
8.2 Hair Shape Modeling......Page 189
8.3 Hair Dynamics......Page 191
8.4 Hair Rendering......Page 192
8.5 Summary......Page 195
8.6 Static Hair Shape Modeling Based on Fluid Flow......Page 196
8.6.1 Hair Shape Model......Page 197
8.6.2 Interactive Hair-Styler......Page 200
8.6.3 Enhancing Realism......Page 203
8.7 Modeling Hair Dynamics Based on Continuum Mechanics......Page 205
8.7.1 Hair as Continuum......Page 206
8.7.2 Single Hair Dynamics......Page 209
8.7.3 Fluid Hair Model......Page 212
8.7.4 Results......Page 216
8.8 Conclusion......Page 217
9.1 Introduction......Page 219
9.2.2 Cloth Mechanics......Page 220
9.3 Mechanical Simulation of Cloth......Page 225
9.3.1 Mechanical Modeling Schemes......Page 226
9.3.2 A Precise Particle-Based Surface Representation......Page 231
9.3.3 Numerical Integration......Page 234
9.4 Collision Techniques......Page 238
9.4.1 Principles of Collision Detection......Page 239
9.4.2 Collision Detection for Cloth Simulation......Page 240
9.4.3 Collisions on Polygonal Meshes......Page 242
9.4.4 Collision Response Schemes......Page 243
9.5.1 Mesh Smoothing......Page 247
9.5.2 Geometrical Wrinkles......Page 249
9.5.3 Advanced Fabric Lighting......Page 250
9.5.4 Toward Real-Time Garment Animation......Page 251
9.6 Designing Garments......Page 253
9.6.1 Garment Design Tools......Page 254
9.6.2 Applications......Page 255
9.7 Conclusion......Page 256
10.1 Introduction......Page 257
10.3 Facial Animation Design......Page 258
10.4 Parameterization......Page 260
10.5 High Level Control of Animation......Page 261
10.6.1 Using Text-to-Speech......Page 265
10.6.2 Phoneme Extraction from Natural Speech......Page 266
10.6.3 Co-articulation......Page 269
10.6.4 Expression Blending......Page 270
10.6.5 Enhancing Realism......Page 271
10.7.1 Data Analysis......Page 272
10.7.2 Principal Component Analysis......Page 273
10.7.3 Contribution of Principal Components......Page 274
10.7.5 Expression Blending Using PCs......Page 277
10.8 Facial Communication......Page 279
10.8.1 Dialogue Generation......Page 280
10.8.3 Emotions......Page 282
10.8.4 Personality and Mood......Page 283
10.9 Putting It All Together......Page 285
10.10 Conclusion......Page 286
11.1 What Is Behavioral Animation?......Page 287
11.1.1 Behavior......Page 288
11.2.1 Perception and Memory......Page 289
11.2.2 Defining Behaviors......Page 291
11.2.3 Interactions......Page 294
11.2.5 Applications......Page 295
11.3.1 Separate the Body and the Brain......Page 296
11.3.2 System Design......Page 297
11.3.3 Animation: A Layered Approach......Page 300
11.3.4 Intelligent Virtual Agent: Simulating Autonomous Behavior......Page 303
11.4 Behavioral Animation and Social Agents......Page 304
11.5.1 Storytelling......Page 306
11.5.2 A Mechanism of Motivated Action Selection......Page 308
11.6 Conclusion......Page 312
12.1 Introduction: Reality vs Virtuality......Page 314
12.4.1 Recognition Methods......Page 316
12.4.2 Model vs Data-Oriented......Page 318
12.4.3 Recognizable Actions......Page 320
12.4.4 Action-Analysis Levels......Page 321
12.4.5 Action Specification......Page 322
12.4.6 Action Recognition Algorithm......Page 324
12.5 Case Studies......Page 325
12.6.1 Sense of Touching......Page 327
12.6.6 Delegate Sub-Tasks......Page 328
12.6.10 Verbal Response......Page 329
13.1 Introduction......Page 330
13.2 Related Work......Page 331
13.2.2 Actor Animation......Page 332
13.3.1 Interaction Features......Page 334
13.3.2 Interpreting Interaction Features......Page 336
13.4.2 Interaction Information......Page 337
13.4.3 Behaviors......Page 339
13.5.1 Interpretation of Plans......Page 341
13.5.2 Manipulation Actions......Page 342
13.6 Case Studies......Page 344
13.6.1 Opening a Drawer......Page 345
13.6.2 Interaction of Multiple Actors......Page 346
13.6.3 Complex Behaviors......Page 347
13.7 Remaining Problems......Page 348
14.1 Introduction......Page 350
14.2 Related Work......Page 351
14.2.1 Crowd Evacuation Simulators......Page 352
14.2.2 Crowd Management Training Systems......Page 354
14.2.3 Sociological Models......Page 355
14.2.4 Computer Graphics......Page 356
14.2.5 Classification of Crowd Methods......Page 357
14.3.1 Hierarchic Model......Page 360
14.3.2 Emergent Crowds......Page 362
14.4.2 Crowd Creation......Page 365
14.4.4 Animated Impostors......Page 366
14.4.5 Impostor Rendering and Texture Generation......Page 367
14.4.6 Texture Refreshment Approach......Page 369
14.4.7 Visibility Issue......Page 370
14.4.8 Factored Impostor......Page 371
14.4.9 Z-Buffer Corrected Impostor......Page 372
14.5.1 Programmed Crowds......Page 373
14.5.2 Guided Crowds......Page 375
14.5.3 Autonomous Crowds......Page 376
14.5.4 Interactive Crowd in Panic Situation......Page 377
14.6 Conclusion......Page 378
15.1 Introduction......Page 380
15.2.1 Texturing......Page 381
15.2.2 Illumination Models......Page 383
15.2.4 Temporal Features......Page 385
15.2.5 Summary of Skin Rendering Techniques......Page 387
15.3 Rendering of Clothes......Page 388
15.3.2 Illumination Models......Page 389
15.3.3 Representation of Milli-Geometry......Page 391
15.3.4 Rendering with Micro/Milli Geometric Detail and BRDF for Woven Clothes......Page 392
15.3.5 Macro-geometry and Interaction with the Environment......Page 397
15.4 Conclusion......Page 399
16.2.1 The Need for a Standard Human Skeleton......Page 400
16.2.2 H-Anim Skeleton Convention......Page 401
16.2.3 Benefits and Limitations of the Standard Skeleton......Page 402
16.2.4 Enforcing Motion Re-use......Page 403
16.3 The MPEG-4 FBA Standard......Page 406
16.3.1 MPEG-4 Body Animation Standard......Page 407
16.3.2 MPEG-4 Face Animation Standard......Page 410
16.4 What’s Next?......Page 418
Appendix A: Damped Least Square Pseudo-Inverse J(+l)......Page 419
Appendix B: H-Anim Joint and Segment Topology......Page 420
Appendix C: Facial Animation Parameter Set......Page 423
References......Page 427
Index......Page 464