Menache Understanding Motion Capture for Computer Animation

2. Auflage 2011
ISBN: 978-0-12-381497-5
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 276 Seiten

Understanding Motion Capture for Computer Animation discusses the latest technology developments in digital design, film, games, medicine, sports, and security engineering. Motion capture records a live-motion event and translates it into a digital context. It is the technology that converts a live performance into a digital performance. In contrast, performance animation is the actual performance that brings life to the character, even without using technology. If motion capture is the collection of data that represents motion, performance animation is the character that a performer represents. The book offers extensive information about motion capture. It includes state-of-the-art technology, methodology, and developments in the current motion-capture industry. In particular, the different ways to capture motions are discussed, including using cameras or electromagnetic fields in tracking a group of sensors. This book will be useful for students taking a course about digital filming, as well as for anyone who is interested in this topic. - Completely revised to include almost 40% new content with emphasis on RF and Facial Motion Capture Systems - Describes all the mathematical principles associated with motion capture and 3D character mechanics - Helps you budget by explaining the costs associated with individualized motion capture projects

Alberto Menache founded Three Space Imagery, Inc. (TSi), a computer graphics and video game developer, in Los Angeles, where he and his team developed proprietary software for motion capture usage in animation. After selling his software to Motion Analysis Corporation, Menache moved on to Pacific Data Images, a computer graphics industry leader, where he is the lead character technical director at the commercial and film effects division. His latest production credits include the film Forces of Nature, commercials for SEGA, Circle K and Pillsbury, the award-winning music video for TLC's 'Waterfalls', and dozens of video games, including Dark Ridge, Messiah and Soul Blade.

Autoren/Hrsg.

Menache, Alberto

Inhaltsverzeichnis

1;Front Cover;1
2;Understanding Motion Capture for Computer Animation - Second Edition;4
3;Copyright;5
4;Dedication;6
5;Contents;8
6;Preface;10
7;Acknowledgments;12
7.1;Thanks to the Following Persons for Their Contributions;12
7.2;Thanks to the Following Persons for Their Support and Assistance;12
8;Chapter 1: Motion Capture Primer;14
8.1;Motion Capture and Performance Animation;15
8.2;History of Performance Animation in the Entertainment Field;16
8.3;Types of Motion Capture;29
8.4;Applications of Motion Capture;50
8.5;Future Applications;58
9;Chapter 2: Motion Capture Case Studies and Controversy;60
9.1;Digital Humans and the Uncanny Valley;63
9.2;Relevant Motion Capture Accounts;65
10;Chapter 3: The Motion Capture Session;88
10.1;Deciding to Use Motion Capture;89
10.2;Preparing for the Session;118
10.3;During the Session;141
10.4;Summary;146
11;Chapter 4: The Motion Data;148
11.1;Motion Data Types and Formats;148
11.2;Writing a Motion Capture Translator;174
12;Chapter 5: Setting up your Character;200
12.1;Setting up a Character with Rotational Data;201
12.2;Setting up a Character with Translational Data;203
12.3;Facial Motion Capture;212
12.4;Tips and Tricks;215
13;Conclusion;230
14;Appendix A: Motion Capture Equipment and Software Manufacturers;232
14.1;Optical Tracking Systems;232
14.2;Electromagnetic Trackers;237
14.3;Sensor-Based Motion Capture Systems;238
14.4;Ultrasonic Systems;240
14.5;Hand Capture Systems;240
14.6;Eye Tracking Systems;241
14.7;Software;242
14.8;Markers and Mocap Suits;244
15;Appendix B: Motion Capture Service Providers;246
15.1;Australia;246
15.2;Austria;247
15.3;Canada;247
15.4;Czech Republic;247
15.5;France;247
15.6;Germany;248
15.7;Greece;248
15.8;Hungary;248
15.9;India;249
15.10;Lithuania;249
15.11;Malaysia;249
15.12;Mexico;249
15.13;Netherlands;250
15.14;Russia;250
15.15;Serbia;250
15.16;Spain;251
15.17;Sweden;251
15.18;Switzerland;251
15.19;United Kingdom;251
15.20;United States;252
16;Appendix C: Web Resources;260
16.1;Motion Capture Associations;260
16.2;Motion Capture Research Institutions and Organizations;260
17;Index;262

Leseproben

1. Motion Capture Primer Chapter Outline Motion Capture and Performance Animation2 History of Performance Animation in the Entertainment Field3 The Rotoscope3 Brilliance4 Pacific Data Images7 The Jim Henson Hour7 Exoskeleton10 deGraf/Wahrman11 Kleiser-Walczak Construction Company12 Homer and Associates13 Party Hardy13 Steam14 Motion Capture Service Bureaus16 Types of Motion Capture16 Optical Motion Capture Systems17 Advantages of Optical Systems20 Disadvantages of Optical Systems21 Radio Frequency Positioning Systems22 Global Positioning System (GPS)22 Real-Time Location Systems (RTLS)23 Local Positioning System24 Electromagnetic Trackers26 Advantages of Magnetic Trackers28 Disadvantages of Magnetic Trackers28 Electromechanical Performance Capture Suits28 Advantages of Electromechanical Body Suits30 Disadvantages of Electromechanical Body Suits30 Digital Armatures30 Facial Motion Capture Systems31 Facial Muscle and Skin Simulators32 Dynamic Blend Shapes33 Computer Vision33 Other Motion Capture Systems34 The Waldo34 Hand Trackers35 Applications of Motion Capture37 Medicine37 Sports39 Entertainment41 Video Games41 Television42 Feature Films43 Law44 Security and Defense44 Engineering45 Future Applications45 Motion Capture and Performance Animation Motion capture is the process of recording a live motion event and translating it into usable mathematical terms by tracking a number of key points in space over time and combining them to obtain a single three-dimensional (3D) representation of the performance. In brief, it is the technology that enables the process of translating a live performance into a digital performance. The captured subject could be anything that exists in the real world and has motion; the key points are the areas that best represent the motion of the subject's different moving parts. These points should be pivot points or connections between rigid parts of the subject. For a human, for example, some of the key points are the joints that act as pivot points and connections for the bones. The location of each of these points is identified by one or more sensors, markers, or potentiometers that are placed on the subject and that serve, in one way or another, as conduits of information to the main collection device. From now on, when speaking generally about these, I will refer to them as “markers.” Performance animation is not the same as motion capture, although many people use the two terms interchangeably. Whereas motion capture pertains to the technology used to collect the motion, performance animation refers to the actual performance that is used to bring a character to life, regardless of the technology used. To obtain it, one must go through the whole process of motion capture and then map the resulting data onto a 3D character. In short, motion capture is the collection of data that represents motion, whereas performance animation is the final product of a character driven by a performer. There are different ways of capturing motion. Some systems use cameras that digitize different views of the performance, which are then used to put together the position of key points, each represented by one or more reflective markers. Others use electromagnetic fields or ultrasound to track a group of sensors. Mechanical systems based on linked structures or armatures that use potentiometers to determine the rotation of each link are also available. Combinations of two or more of these technologies exist, and newer technologies are also being tested, all aiming for one result: real-time tracking of an unlimited number of key points with no space limitations at the highest frequency possible with the smallest margin of error. This is the Holy Grail of motion capture and probably the mission statement of every motion capture hardware manufacturer's research department. I later discuss how each of the current technologies falls short in this respect. History of Performance Animation in the Entertainment Field The Rotoscope Motion capture in the entertainment field is the descendant of rotoscoping, a technique still used by some traditional animation studios to copy realistic motion from film footage onto cartoon characters. The rotoscope device was invented and patented by cartoonist Max Fleischer in 1915, with the intent of automating the production of cartoon films. The device projected live-action film, a frame at a time, onto a light table, allowing cartoonists to trace the frame's image onto paper. The first cartoon character ever to be rotoscoped was Koko the Clown. Fleischer's brother, Dave, acted out Koko's movements in a clown suit. Fleischer wanted to use Koko to convince the big studios to use the new process for their cartoon projects. The sale was difficult because it had taken Fleischer about a year to produce the initial 1-min cartoon using the technique, so he couldn't market it as a mass production tool. Eventually, Fleischer realized that rotoscoping would be a viable technique only for certain shots that required realistic motion. Walt Disney Studios used some rotoscoping in 1937 to create the motion of human characters in Snow White. Snow White herself and the Prince were partially rotoscoped. The decision to use rotoscoping wasn't a matter of cost, but of realistic human motion. In fact, Snow White went tremendously over budget due to the complexity of the animation. Rotoscoping has been adopted over the years by many cartoon studios, but few actually admit using it because many people in the animation industry consider it cheating and a desecration of the art of animation. A two-dimensional (2D) approach, rotoscoping was designed for traditional, hand-drawn cartoons. The advent of 3D animation brought about the birth of a new, 3D way of rotoscoping. Hence, motion capture. Brilliance Some of the current motion capture technologies have been around for decades, being used in different applications for medical and military purposes. Motion capture in computer graphics was first used in the late 1970s and early 1980s in the form of research projects at schools such as Simon Fraser University, Massachusetts Institute of Technology, and New York Institute of Technology, but it was used in actual production only in the mid-1980s. In late 1984, Robert Abel appeared on a talk show and was asked if he would soon be able to counterfeit people digitally. “We are a long ways from that,” he replied. “We haven't even figured out human motion, which is the basis, and that's a year away.” A week and a half later, Abel received a visit on a Friday afternoon from a creative director from Ketchum, a prominent advertising agency. The visitor brought six drawings of a very sexy woman made out of chrome. She was to have Kathleen Turner's voice and would be the spokesperson for the National Canned Food Information Council, an association formed by Heinz, Del Monte, Campbell's, and a number of big players that sold canned food. They felt they had to make a powerful statement because the idea of buying food in cans was becoming obsolete, so they wanted to do something...