MoCap for Artists: Workflow and Techniques for Motion Capture Book

Acknowledgments     xi
Introduction     xiii
An Overview and History of Motion Capture     1
About This Book     1
History of Mocap     2
Early attempts     2
Rotoscoping     4
Beginning of digital mocap     6
Types of Mocap     8
Optical mocap systems     8
Magnetic mocap systems     10
Mechanical mocap systems     11
Preproduction     13
Importance of Preproduction     13
Pre-capture Planning     13
Script     14
Storyboard     15
Shot list     15
Animatic     16
Preparation for Capture     17
Talent     17
Marker sets     18
What are the system limitations?     18
What kind of motion will be captured?     19
Know the anatomy     19
Capture volume     21
Shot list     23
Capture schedule     24
Rehearsals     25
Props     26
Suits and markers     28
Pipeline     31
Setting up a Skeleton for a 3DCharacter     31
Calibrations     33
System calibration     33
Subject calibration     34
Capture Sessions     36
Audio and video references     36
Organization     37
Preventing occlusions     38
Cleaning Data     39
Editing Data     40
Applying Motions to a 3D Character     43
Rendering and Post-production     44
Cleaning and Editing Data     47
Cleaning Marker Data     47
Types of data     47
Optical marker data (translational data)     47
Translational and rotational data     47
Skeletal data     48
What to clean and what not?     48
What not to clean?     48
What to clean?     49
Labeling/identifying     49
Data cleaning methods     51
Eliminating gaps     51
Eliminating spikes     54
Rigid body     56
Filters     59
When to stop?     61
Applying Marker Data to the Skeleton     62
Actor     63
Skeleton     67
Character      69
Skeletal Editing     73
Retargeting     73
Reducing need for retargeting     73
Scaling a skeleton     75
Fixing foot sliding     76
Working on the spine     78
Blending Motions     79
Selecting a blending point     80
Matching positions     86
Dealing with less than ideal cases     86
Inverse Kinematics     88
Floor Contact     88
Rigid Body     92
Looping Motion     93
Getting motion ready     93
Setting up the loop     94
Walking down the z-axis     94
Taking out the translation     95
Poses     98
Deciding what to use     98
Creating a pose     98
Key-framing a pose     100
Data Application - Intro Level: Props     103
A Stick with Two Markers     103
When it fails: Occlusion     103
When it fails: Rotation     105
A Stick with Three Markers     105
Three markers with equal distances     105
Three markers on a single straight line     106
Placement of three markers that works      108
Flexible Objects     109
Data Application - Intermediate Level: Decomposing and Composing Motions     113
Mapping Multiple Motions     113
Decomposing and composing upper and lower body motions     113
Synchronizing upper and lower body motions     116
Balance     118
Breaking Motion Apart     119
When you don't need all the motion     119
Re-use of motion data for non-motion purposes     122
Data Application - Advanced Level: Integrating Data with Character Rigs     125
Mocap as Forward Kinematics Animation     125
Key-frame Animation with Inverse Kinematics     127
Key-framing     128
IK     129
Integrating Mocap Animation and Key-frame Animation     130
Why do we want to do that?     131
Setting up a skeleton for FK and IK     131
Adding key-frame animation to mocap     134
Hand Motion Capture     137
Anatomy of a Hand     137
Rig and Marker Set for the Hand     141
Rigid hand     141
Mitten     143
Mitten with an independent thumb     144
Mitten that stretches     146
Ultimate      146
Capturing Hands     149
Facial Motion Capture     151
Anatomy of a Face     151
Camera Setup and Capture     154
Facial Rig     155
Facial rig with discrete joints     155
Facial rig with muscles     156
Facial rig with IK     157
Marker Set     159
Facial Data Stabilization     161
Facial Data Editing     164
Puppetry Capture     167
Background     167
Benefits     168
Ideas/Inspiration     169
Performance     170
Projects     171
Methods     173
Real Time     176
Mocap Data and Math     179
How Data Is Created     179
Optical systems     179
Magnetic systems     180
Mechanical systems     180
Data Types and Formats     181
C3D     181
ASF/AMC     181
BVH     182
FBX     183
Coordinates and Coordinate Systems     183
2D and 3D coordinate systems     184
Cartesian, spherical, and cylindrical coordinate systems      184
Right-handed and left-handed systems     185
Object space and world space     186
Order of Transformation     186
Euler Angle     188
Gimbal Lock     190
Quaternions     194
Bibliography     195
Shot List for Juggling Cow     197
Sample Mocap Production Pipeline and Data Flow Chart     199
Glossary     201
Index     207