book

MoCap for Artists

by Midori Kitagawa, Brian Windsor

October 2020

Beginner

232 pages

6h 26m

English

Routledge

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Front Cover
Half Title
Title Page
Copyright
Contents
Acknowledgments
Introduction
Chapter 1: An Overview and History of Motion Capture
1.1 About This Book1.2 History of Mocap1.2.1 Early attempts1.2.2 Rotoscoping1.2.3 Beginning of digital mocap1.3 Types of Mocap1.3.1 Optical mocap systems1.3.2 Magnetic mocap systems1.3.3 Mechanical mocap systems
Chapter 2: Preproduction
2.1 Importance of Preproduction2.2 Pre-capture Planning2.2.1 Script2.2.2 Storyboard2.2.3 Shot list2.2.4 Animatic2.3 Preparation for Capture2.3.1 Talent2.3.2 Marker sets2.3.2.1 What are the system limitations?2.3.2.2 What kind of motion will be captured?2.3.2.3 Know the anatomy2.3.3 Capture volume2.3.4 Shot list2.3.5 Capture schedule2.3.6 Rehearsals2.3.7 Props2.3.8 Suits and markers
Chapter 3: Pipeline
3.1 Setting up a Skeleton for a 3D Character3.2 Calibrations3.2.1 System calibration3.2.2 Subject calibration3.3 Capture Sessions3.3.1 Audio and video references3.3.2 Organization3.3.3 Preventing occlusions3.4 Cleaning Data3.5 Editing Data3.6 Applying Motions to a 3D Character3.7 Rendering and Post-production

Chapter 4: Cleaning and Editing Data
4.1 Cleaning Marker Data4.1.1 Types of data4.1.1.1 Optical marker data (translational data)4.1.1.2 Translational and rotational data4.1.1.3 Skeletal data4.1.2 What to clean and what not?4.1.2.1 What not to clean?4.1.2.2 What to clean?4.1.3 Labeling/identifying4.1.4 Data cleaning methods4.1.4.1 Eliminating gaps4.1.4.2 Eliminating spikes4.1.4.3 Rigid body4.1.4.4 Filters4.1.5 When to stop?4.2 Applying Marker Data to the Skeleton4.2.1 Actor4.2.2 Skeleton4.2.3 Character
Chapter 5: Skeletal Editing
5.1 Retargeting5.1.1 Reducing need for retargeting5.1.2 Scaling a skeleton5.1.3 Fixing foot sliding5.1.4 Working on the spine5.2 Blending Motions5.2.1 Selecting a blending point5.2.2 Matching positions5.2.3 Dealing with less than ideal cases5.3 Inverse Kinematics5.4 Floor Contact5.5 Rigid Body5.6 Looping Motion5.6.1 Getting motion ready5.6.2 Setting up the loop5.6.2.1 Walking down the z-axis5.6.2.2 Taking out the translation5.7 Poses5.7.1 Deciding what to use5.7.2 Creating a pose5.7.3 Key-framing a pose
Chapter 6: Data Application – Intro Level: Props
6.1 A Stick with Two Markers6.1.1 When it fails: Occlusion6.1.2 When it fails: Rotation6.2 A Stick with Three Markers6.2.1 Three markers with equal distances6.2.2 Three markers on a single straight line6.2.3 Placement of three markers that works6.3 Flexible Objects
Chapter 7: Data Application – Intermediate Level: Decomposing and Composing Motions
7.1 Mapping Multiple Motions7.1.1 Decomposing and composing upper and lower body motions7.1.2 Synchronizing upper and lower body motions7.2 Balance7.3 Breaking Motion Apart7.3.1 When you don’t need all the motion7.3.2 Re-use of motion data for non-motion purposes
Chapter 8: Data Application – Advanced Level: Integrating Data with Character Rigs
8.1 Mocap as Forward Kinematics Animation8.2 Key-frame Animation with Inverse Kinematics8.2.1 Key-framing8.2.2 IK8.3 Integrating Mocap Animation and Key-frame Animation8.3.1 Why do we want to do that?8.3.2 Setting up a skeleton for FK and IK8.3.3 Adding key-frame animation to mocap
Chapter 9: Hand Motion Capture
9.1 Anatomy of a Hand9.2 Rig and Marker Set for the Hand9.2.1 Rigid hand9.2.2 Mitten9.2.3 Mitten with an independent thumb9.2.4 Mitten that stretches9.2.5 Ultimate9.3 Capturing Hands
Chapter 10: Facial Motion Capture
10.1 Anatomy of a Face10.2 Camera Setup and Capture10.3 Facial Rig10.3.1 Facial rig with discrete joints10.3.2 Facial rig with muscles10.3.3 Facial rig with IK10.4 Marker Set10.5 Facial Data Stabilization10.6 Facial Data Editing
Chapter 11: Puppetry Capture
11.1 Background11.2 Benefits11.3 Ideas/Inspiration11.4 Performance11.5 Projects11.6 Methods11.7 Real Time
Chapter 12: Mocap Data and Math
12.1 How Data Is Created12.1.1 Optical systems12.1.2 Magnetic systems12.1.3 Mechanical systems12.2 Data Types and Formats12.2.1 C3D12.2.2 ASF/AMC12.2.3 BVH12.2.4 FBX12.3 Coordinates and Coordinate Systems12.3.1 2D and 3D coordinate systems12.3.2 Cartesian, spherical, and cylindrical coordinate systems12.3.3 Right-handed and left-handed systems12.3.4 Object space and world space12.4 Order of Transformation12.5 Euler Angle12.6 Gimbal Lock12.7 Quaternions
Bibliography
Appendix A: Shot List for Juggling Cow
Appendix B: Sample Mocap Production Pipeline and Data Flow Chart
Glossary
Index

Content preview from MoCap for Artists

5 Skeletal Editing

This chapter is about various ways to edit skeletal data, that is, data that’s rotational in nature. The skeletal editing techniques that will be discussed include retargeting, blending, inverse kinematics (IK), floor contact, rigid body, looping, and poses. Let’s start with retargeting.

5.1 Retargeting

When we have mocap data that has been applied to a target skeleton, it is very possible that the source skeleton (the skeleton in the data) and the target skeleton do not have the same proportion. That is almost always the case between the capture subject whom markers were attached to and the 3D character that you want the motion to go onto. Some allowances must be made for the proportional differences in order for the motion ...

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MoCap for Artists

by Midori Kitagawa, Brian Windsor