Computer Animation Complete: All-in-One: Learn Motion Capture, Characteristic, Point-Based, and Maya Winning Techniques

591 Pages·2009·15.24 MB·English

by  Rick Parent

Contents i
i
Computer Animation
Complete
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Computer Animation
Complete
All-in-One: Learn Motion Capture,
Characteristic, Point-Based, and
Maya Winning Techniques
Rick Parent, David S. Ebert, David A. D. Gould, Markus Gross, Chris
Kazmier, Richard Keiser, Charles J Lumsden, Alberto Menache,
Matthias MÜller-Fischer, F. Kenton Musgrave, Mark Pauly, Darwyn
Peachey, Ken Perlin, Hanspeter Pfi ster, Jason Sharpe, Martin
Wicke, Mark R. Wilkins, Nicholas Woolridge, Steven Worley
AMSTERDAM • BOSTON • HEIDELBERG • LONDON
NEW YORK • OXFORD • PARIS • SAN DIEGO
SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO
Morgan Kaufmann Publishers is an imprint of Elsevier
Morgan Kaufmann Publishers is an imprint of Elsevier.
30 Corporate Drive, Suite 400,
Burlington, MA 01803, USA
This book is printed on acid-free paper. (cid:2)
© 2010 by Elsevier Inc. All rights reserved.
Chapters 1, 2, 5, 7, were originally published in Computer Animation, by Rick Parent.
Chapters 3, 4, and online Bonus Chapter 14, were originally published in Understanding Motion Capture for
Computer Animation and Video Games, by Alberto Menache.
Chapter 6 was originally published in Texturing and Modeling: A Procedural Approach, by David Ebert, F. Kenton
Musgrave, Darwyn Peachey, Ken Perlin, and Steven Worley.
Chapter 8 was originally published in In Silico, by Jason Sharpe, Charles J. Lumsden, and Nicholas Woolridge.
Chapter 9 was originally published in Point-Based Graphics, by Makus Gross and Hanspeter Pfi ster
Chapters 10, 12, 13, and online Bonus Chapter 15, were originally published in MEL Scripting for Maya Animators,
by Mark R. Wilkins and Chris Kazmier.
Chapter 11 was originally published in Complete Maya Programming Vol.I, by David A. D. Gould.
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Library of Congress Cataloging-in-Publication Data
Computer animation complete: all-in-one: learn motion capture, characteristic, point-based,
and Maya winning techniques/Rick Parent ... [et al.].
p. cm.
Includes bibliographical references and index.
ISBN 978-0-12-375078-5 (pbk. : alk. paper)
1. Computer animation. 2. Maya (Computer fi le) I. Parent, Rick.
TR897.7.C65 2010
006.6’96--dc22
2009017063
British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library.
ISBN: 978-0-12-375078-5
For information on all Morgan Kaufmann publications,
visit our Web site at www.mkp.com or www.elsevierdirect.com
Printed in the United States of America.
09 10 11 12 13 5 4 3 2 1
Typeset by: diacriTech, Chennai, India
Contents
Contributing Authors ...............................................................................................xiii
PART I INTRODUCTION TO COMPUTER ANIMATION
CHAPTER 1 Introduction ....................................................................................3
1.1 Perception ..........................................................................................4
1.2 The Heritage of Animation ................................................................6
1.2.1 Early Devices ............................................................................7
1.2.2 The Early Days of Conventional Animation .............................9
1.2.3 Disney ......................................................................................10
1.2.4 Contributions of Others ..........................................................12
1.2.5 Other Media for Animation .....................................................12
1.2.6 Principles of Animation ..........................................................13
1.2.7 Principles of Filmmaking ........................................................14
1.3 Animation Production ......................................................................16
1.3.1 Sound .......................................................................................18
1.4 Computer Animation Production .....................................................19
1.4.1 Computer Animation Production Tasks ..................................21
1.4.2 Digital Editing .........................................................................22
1.4.3 Digital Video ...........................................................................25
1.4.4 Digital Audio ...........................................................................26
1.5 A Brief History of Computer Animation ..........................................27
1.5.1 Early Activity (pre-1980) .........................................................27
1.5.2 The Middle Years (The 1980s) ...............................................30
1.5.3 Animation Comes of Age (The mid-1980s and beyond) .........32
1.6 Chapter Summary .............................................................................35
References ........................................................................................36
CHAPTER 2 Technical Background ...................................................................39
2.1 Spaces and Transformations ............................................................40
2.1.1 The Display Pipeline ...............................................................41
2.1.2 Homogeneous Coordinates
and the Transformation Matrix ...............................................45
2.1.3 Compound Transformation: Concatenating
Transformation Matrices ........................................................46
2.1.4 Basic Transformations .............................................................47
2.1.5 Representing an Arbitrary Orientation ..................................49
2.1.6 Extracting Transformations from a Matrix ............................53
v
vvii CCoonntteennttss
2.1.7 Description of Transformations in the Display Pipeline ........54
2.1.8 Error Considerations ..............................................................56
2.2 Orientation Representation .............................................................60
2.2.1 Fixed-Angle Representation ....................................................61
2.2.2 Euler Angle Representation ...................................................63
2.2.3 Angle and Axis Representation..............................................64
2.2.4 Quaternion Representation ...................................................65
2.2.5 Exponential Map Representation ............................................67
2.3 Chapter Summary ............................................................................68
References ........................................................................................68
PART II MOTION CAPTURE TECHNIQUES
CHAPTER 3 Motion Capture Primer ..................................................................71
3.1 Motion Capture and Performance Animation .................................72
3.2 History of Performance Animation
in the Entertainment Field ...............................................................72
3.2.1 The Rotoscope .......................................................................72
3.2.2 Brilliance ................................................................................73
3.2.3 Pacifi c Data Images .................................................................75
3.2.4 deGraf/Wahrman ...................................................................80
3.2.5 Kleiser–Walczak Construction Company ..............................80
3.2.6 Homer and Associates .............................................................81
3.3 Types of Motion Capture .................................................................84
3.3.1 Optical Motion Capture Systems ............................................84
3.3.2 Electromagnetic Trackers ......................................................89
3.3.3 Electromechanical Suits .........................................................92
3.3.4 Digital Armatures ...................................................................94
3.3.5 Other Motion Capture Systems ..............................................97
3.4 Applications of Motion Capture ....................................................100
3.4.1 Medicine ...............................................................................100
3.4.2 Sports ....................................................................................102
3.4.3 The Entertainment Industry .................................................102
3.4.4 Law ........................................................................................104
CHAPTER 4 The Motion Data ..........................................................................105
4.1 Motion Data Types and Formats .....................................................105
4.1.1 The Acclaim File Format........................................................107
4.1.2 The .asf File ..........................................................................108
4.1.3 The .amc File .........................................................................111
4.1.4 The .bva File Format ..............................................................112
4.1.5 The .bvh File Format..............................................................113
Contents vii
4.1.6 The .trc File Format ...............................................................117
4.1.7 The .htr File Format ...............................................................119
4.2 Writing a Motion Capture Translator ............................................128
PART III ANIMATING SUBSTANCES
CHAPTER 5 Animating Facial Features ...........................................................167
5.1 The Human Face .............................................................................168
5.1.1 Anatomic Structure ...............................................................168
5.1.2 The Facial Action Coding System (FACS) ..............................169
5.2 Facial Models ..................................................................................170
5.2.1 Creating a Continuous Surface Model ..................................172
5.2.2 Textures ................................................................................178
5.3 Animating the Face .........................................................................178
5.3.1 Parameterized Models ...........................................................178
5.3.2 Blend Shapes .........................................................................179
5.3.3 Muscle Models ......................................................................180
5.3.4 Expressions ...........................................................................184
5.3.5 Summary ...............................................................................184
5.4 Lip-Sync Animation ........................................................................185
5.4.1 Articulators of Speech ...........................................................185
5.4.2 Phonemes .............................................................................186
5.4.3 Coarticulation........................................................................187
5.4.4 Prosody .................................................................................188
5.5 Chapter Summary ..........................................................................188
References ......................................................................................188
CHAPTER 6 Animating Solid Spaces ...............................................................191
6.1 Animation Paths .............................................................................192
6.2 Animating Solid Textures ...............................................................193
6.2.1 Marble Forming .....................................................................194
6.2.2 Marble Moving ......................................................................196
6.2.3 Animating Solid-Textured Transparency ..............................197
6.3 Animation of Gaseous Volumes .....................................................200
6.3.1 Helical Path Effects ..............................................................200
6.4 Three-Dimensional Tables .............................................................208
6.4.1 Accessing the Table Entries ..................................................209
6.4.2 Functional Flow Field Tables................................................209
6.4.3 Functional Flow Field Functions ...........................................210
6.4.4 Combinations of Functions ...................................................215
6.5 Animating Hypertextures ...............................................................218
6.5.1 Volumetric Marble Formation ...............................................218
viii Contents
6.6 Particle Systems: Another Procedural Animation Technique ........219
6.7 Conclusion ......................................................................................223
References ......................................................................................223
CHAPTER 7 Animating Fluids and Gases .........................................................225
7.1 Specifi c Fluid Models .....................................................................226
7.1.1 Models of Water ....................................................................226
7.1.2 Models of Clouds (by David Ebert).......................................238
7.1.3 Models of Fire ........................................................................249
7.2 Computational Fluid Dynamics ......................................................252
7.2.1 General Approaches to Modeling Fluids ...............................252
7.2.2 CFD Equations .......................................................................254
7.3 Chapter Summary ...........................................................................259
References ......................................................................................259
CHAPTER 8 Animating Biology .......................................................................263
8.1 Introduction ...................................................................................264
8.2 Animation and Film Perception .....................................................265
8.2.1 Seeing, in Brief .....................................................................265
8.2.2 Seeing Motion and Animation ..............................................267
8.3 The Animator’s Workfl ow .............................................................268
8.3.1 Story: The Workfl ow’s Driving Force ...................................268
8.4 The Three-Stage Workfl ow .............................................................270
8.4.1 Workfl ow Stage 1: Preproduction .........................................271
8.4.2 Workfl ow Stage 2: Production .............................................278
8.4.3 Workfl ow Stage 3: Postproduction ......................................288
8.4.4 Putting It All Together .........................................................288
8.5 Animation ......................................................................................289
8.6 Maya ...............................................................................................289
8.6.1 Procedural versus Keyframe Animation ..............................289
8.6.2 Keyframes and Memory .......................................................290
8.6.3 The Animation Menu Set ......................................................291
8.6.4 Setting Keys ..........................................................................291
8.6.5 Auto Keyframe .....................................................................292
8.6.6 Graphing Animation ............................................................293
8.6.7 Deleting Keys .......................................................................295
8.6.8 Time Units ............................................................................295
8.6.9 Playback Settings ..................................................................296
8.7 Tutorial 08.01: A Keyframe Animation ..........................................296
8.7.1 Preparation ...........................................................................297
8.7.2 Set the Keyframes .................................................................298
8.7.3 Play, Scrub, and Stop the Animation ....................................298
8.7.4 Edit the Animation Curves ...................................................299
Contents ix
8.7.5 The Graph Editor Outliner ...................................................300
8.7.6 The Graph Editor Graph View .............................................300
8.7.7 The Graph Editor Toolbar .....................................................302
8.7.8 Moving Keys .........................................................................302
8.8 Animation Nodes in the Hypergraph and Attribute Editor ...........303
8.9 Tutorial 08.02: A Simple Procedural Animation ............................303
8.9.1 Animation Expressions in Brief ............................................304
8.9.2 Create an Animation Expression ..........................................304
8.9.3 Animation Expression Nodes ...............................................306
8.10 Summary ........................................................................................307
References ......................................................................................308
PART IV OTHER METHODS
CHAPTER 9 Point-Based Animation .................................................................311
9.1 Introduction ...................................................................................312
9.2 Meshless Finite Elements ...............................................................312
9.2.1 Overview ..............................................................................312
9.2.2 Continuum Elasticity ............................................................313
9.2.3 Meshless Discretization ........................................................318
9.2.4 Moving Least Squares Interpolation .....................................319
9.2.5 Updating Strains and Stresses ...............................................321
9.2.6 Computation of Forces via Strain Energy ............................321
9.2.7 Animation of Elastic Objects ................................................323
9.2.8 Plasticity ...............................................................................325
9.2.9 Passive Surfel Advection .......................................................326
9.2.10 Conclusion .........................................................................327
9.3 Animation of Fracturing Material ...................................................327
9.3.1 Overview ..............................................................................327
9.3.2 Historical Background ..........................................................329
9.3.3 Modeling of Discontinuities .................................................330
9.3.4 Surface Model .......................................................................331
9.3.5 Crack Initiation and Propagation .........................................333
9.3.6 Topology Control ..................................................................334
9.3.7 Volumetric Sampling ............................................................336
9.3.8 Fracture Control ...................................................................338
9.3.9 Simulation Pipeline ..............................................................339
9.3.10 Conclusion .........................................................................340
9.4 Fluid Simulation .............................................................................340
9.4.1 Overview ..............................................................................340
9.4.2 Simulation Methods ..............................................................341
9.4.3 Smoothed Particle Hydrodynamics ......................................342