Complete Maya Programming, Vol. II: An In-Depth Guide to 3D Fundamentals, Geometry, and Modeling (Morgan Kaufmann Series in Computer Graphics and Geometric ... Morgan Kaufmann Series in Computer Graphics)

737 Pages·2005·2.15 MB·English

by  M.I.Ex. (auth.), David Gould

A great follow-up to Volume Lt Volume II is an in-depth guide to the mathematical and
geometric concepts indispensable to advanced Maya programmers.
~Larry Gritz, Exluna/NVIDIA
From Volume I of Complete Maya Programming.
David's book is an excellent learning tool and reference for novice and veteran Maya
developers alike. Maya developers can become more productive with MEL and the Maya
API by applying what they learn from this book.
Tracy Narine, Maya API Technical Lead, Alias
David Gould is an expert at using, programming, and teaching Maya, and it shows. People
who need to program Maya will find this book essential. Even Maya users who don't intend
to do extensive programming should read this book for a better understanding of what's
going on under the hood. Compact yet thorough, it covers both MEL and the C+ + APL and
is written to be informative for both novice and expert programmers. Highly recommended,t
--Larry Gritz, Exluna/NVIDIA, co-author of Advanced RenderMan
This book should be required reading for all Maya programmers, novice and expert
alike. For the novice, it provides a thorough and wonderfully well thought-out hands-on
tutorial and introduction to Maya. The book's greatest contribution, however, is that in
it David shares his deep understanding of Maya's fundamental concepts and architec-
ture, so that even the expert can learn to more effectively exploit Maya's rich and power-
ful programming interfaces.
~Philip J. Schneider, Industrial Light & Magic, co-author of
Geometric Toolsf or Computer Graphics
Having provided a technical review of David Gould's Complete Maya Programming,
I must say that this book is the definitive text for scripting andplug-in development for
Maya. Never before has there been such a concise and clearly written guide to program-
ruing for Maya. Any user smart enough to pick up this book would be better offf or it.
~Chris Rock, technical director at "a Large Animation Studio
in Northern California"
I f you ever wanted to open the Maya toolbox, this is your guide. With clear step-by-step
instructions, you will soon be able to customize and improve the application, as well as create
your own extensions, either through the MEL scripting language or the full C+ + APL
~Christophe Hery, Industrial Light & Magic
The Morgan Kaufmann Series in Computer Graphics and Geometric Modeling
Complete Maya Programming Volume II: Computer Animation: Algorithms and Techniques
An In-depth Guide to 3D Fundamentals, Geometry, Rick Parent
and Modeling
The Computer Animator's Technical Handbook
David A. D. Gould
Lynn Pocock and Judson Rosebush
High Dynamic Range Imaging:
Advanced RenderMan:
Data Acquisition, Manipulation, and Display
Creating CGIf or Motion Pictures
Erik Reinhard, Greg Ward, Sumanta Pattanaik,
Anthony A. Apodaca and Larry Gritz
and Paul Debevec
Curves and Su~Caces in Geometric Modeling:
MEL Scriptingf or Maya Animators, Second Edition
Theory and Algorithms
Mark R. Wilkins and Chris Kazmier
Jean Gallier
Advanced Graphics Programming Using OpenGL
Andrew Glassner's Notebook:
Tom McReynolds and David Blythe
Recreational Computer Graphics
Digital Geometry: Andrew S. Glassner
Geometric Methods for Digital Picture Analysis
Warping and Morphing of Graphical Objects
Reinhard Klette and Azriel Rosenfeld
Jonas Gomes, Lucia Darsa, Bruno Costa,
Digital Video and HD TV[: and Luiz Velho
Algorithms and Intofaces
tim Blinn's Corner:
Charles Poynton
Dirty Pixels
Real- Hme Shader Programming Jim Blinn
Ron Fosner
Rendering with Radiance:
Complete Maya Programming: The Art and Science of Lighting Visualization
An Extensive Guide to MEL and the C+ + API Greg Ward Larson and Rob Shakespeare
David A. D. Gould
Introduction to Implicit Surfaces
Texturing & Modeling: Edited by Jules Bloomenthal
A ProceduralApproach, Third Edition
Jim Blinn's Corner:
David S. Ebert, E Kenton Musgrave, Darwyn
A Trip Down the Graphics Pipeline
Peachey, Ken Perlin, and Steven Worley
Jim Blinn
Geometric Toolsf or Computer Graphics
Interactive Curves and Surfaces:
Philip Schneider and David H. Eberly
A Multimedia Tutorial on CAGD
Understanding ½rtual Reality: Alyn Rockwood and Peter Chambers
Inte~Cace, Application, and Design
Waveletsf or Computer Graphics:
William B. Sherman and Alan R. Craig
Theory and Applications
tim Blinn's Corner: Eric J. Stollnitz, Tony D. DeRose,
Notation, Notation, Notation and David H. Salesin
Jim Blinn
Principles of Digital Image Synthesis
Level of Detail for 3D Graphics Andrew S. Glassner
David Luebke, Martin Reddy, Jonathan D. Cohen,
Radiosity & Global Illumination
Amitabh Varshney, Benjamin Watson, and Robert
Francois X. Sillion and Claude Puech
Huebner
User Interface Management Systems:
Pyramid Algorithms:
Models and Algorithms
A Dynamic Programming Approach to Curves
Dan R. Olsen, Jr.
and Surfacesf or Geometric Modeling
Making Them Move: Mechanics, Control, and
Ron Goldman
Animation ofA rticulated Figures
Non-Photorealistic Computer Graphics:
Edited by Norman I. Badler, Brian A. Barsky,
Modeling, Rendering, and Animation
and David Zeltzer
Thomas Strothotte and Stefan Schlechtweg
Geometric and Solid Modeling: An Introduction
Curves and Surfacesf or CAGD:
Christoph M. Hoffmann
A Practical Guide, Fifth Edition
An Introduction to Splinesf or Use in Computer
Gerald Farin
Graphics and Geometric Modeling
Subdivision Methodsf or Geometric Design:
Richard H. Bartels, John C. Beatty,
A Constructive Approach
and Brian A. Barsky
Joe Warren and Henrik Weimer
COMPLETE MAYA
P RO GRAMMI N G
VOLUME I 1
,
David A. D. Gould
AMSTERDAM BOSTON HEIDELBERG
LONDON NEW YORK OXFORD
PARIS SAN DIEGO SAN FRANCISCO
SINGAPORE SYDNEY TOKYO
ELSEVIER Morgan Kaufmann Publishers is an imprint of Elsevier M 0 R G A N K A U F M A N N P U B L I S H E R S
Senior Editor Tim Cox
Publishing Services Manager Simon G. Crump
Senior Project Manager Angela G. Dooley
Assistant Editor Richard Camp
Editorial Assistant Jessica Evans
Cover Design Direction Cate Rickard Barr
Cover Illustration Sean Platter, Studio Splatter
Text Design Direction Julio Esperas
Composition Integra Software Services Pvt. Ltd., Pondicherry, India
Technical Illustration Dartmouth Publishing Inc.
Copyeditor Daril Bentley
Proofreader Phyllis Coyne et al.
Indexer Northwind Editorial
Interior Printer Maple-Vail Manufacturing Group
Cover Printer Phoenix Color Corp.
Morgan Kaufmann Publishers is an imprint of Elsevier.
500 Sansome Street, Suite 400, San Francisco, CA 94111
This book is printed on acid-f?ee paper.
© 2005 by Elsevier Inc. All rights reserved.
Designations used by companies to distinguish their products are often claimed as trademarks or registered
trademarks. In all instances in which Morgan Kaufmann Publishers is aware of a claim, the product names
appear in initial capital or all capital letters. Readers, however, should contact the appropriate companies for
more complete information regarding trademarks and registration.
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by
any means---electronic, mechanical, photocopying, scanning, or otherwisemwithout prior written permission
of the publisher.
Permissions may be sought directly from Elsevier's Science & Technology Rights Department in Oxford, UK"
phone: [phone], fax: [phone], e-mail:
To Agnes, my foundation.
About the Author
With over thirteen years of experience in the computer graphics industry, David Gould
has pursued the dual paths of programmer and artist. This rare ability to combine both
the technical and artistic has won him many awards and credits. He has played a key
role in the development of an eclectic mix of technology, including an award-winning
laser rendering system for Pangolin. He developed software for controlling the Kuper
motion-control rig, as well as the Monkey stop-motion puppet. He personally devel-
oped Illustrate, the market leading toon and technical illustration renderer. This
renderer is used by NASA, British Aerospace, Walt Disney Imagineering, and Sony
Pictures Entertainment, among others.
David's career has spanned a wide variety of companies and continents. In Paris,
he supervised the production of 3D stereoscopic scientific films, including the award
winning film Inside the Cell. In London he developed a patented facial animation
system. Further broadening his experiences, he worked in New York in the post-
production industry where he contributed to many high-profile commercials.
While at Walt Disney Feature Animation, Los Angeles, David developed cutting-
edge animation and modeling technology that was used in the production of their
animated feature films. He diversified further by joining Exluna, Berkeley, the soft-
ware company founded by former Pixar rendering researchers, including Larry Gritz.
While there, he played an active role in the design and development of Entropy, the
Renderman-compatible renderer, as well as other products. David continued his
rendering development efforts while at NVIDIA, in Santa Clara, California, by aid-
ing in the design of their future 3D graphics chips.
David has since joined the academy awarding winning studio WETA Digital in
New Zealand. Having completed work on The Lord of the Rings trilogy he is currently
working on King Kong. His varied roles in production include research and develop-
ment, shader writing, lighting, and effects.
Contents
Preface xiv
1 Introduction I
1.1 Example Files 3
1.1.1 Compiling Example Plug-ins 3
1.1.2 Sourcing Example MEL Scripts 3
1.2 Executing MEL Code in the Script Editor 5
2 Points 9
2.1 Dimensions 9
2.2 Cartesian Coordinates 9
2.3 Homogeneous Coordinates 10
2.4 Polar and Spherical Coordinates 11
2.5 Conversions 12
2.5.1 Cartesian to Homogeneous 12
2.5.2 Homogeneous to Cartesian 13
2.5.3 Cartesian to Polar 13
2.5.4 Polar to Cartesian 13
2.5.5 Cartesian to Spherical 14
2.5.6 Spherical to Cartesian 14
2.6 MEL 15
2.7 C++API 16
2.8 Locators 17
.j Vectors 19
3.1 MEL 19
3.2 C++API 20
3.3 Adding 21
3.4 Subtracting 22
3.5 Scaling 22
3.6 Length 23
3.6.1 MEL 25
3.6.2 Ct+ API 26
3.7 Distance Between Points 26
3.7.1 MEL 26
3.7.2 C++A PI 27
3.8 Normalizing Vectors 27
3.8.1 MEL 27
3.8.2 C t t API 28
3.9 Dot Product 28
3.9.1 Angle Between 29
3.9.2 Length Squared 31
3.9.3 Perpendicular Projection 31
3.10 Cross Product 35
3.10.1 Perpendicular Vector 35
3.10.2 Area ofTriangle 38
3.1 1 Points Versus Vectors 40
Rotations 43
4.1 Angles 43
4.1.1 MEL 43
4.1.2 C++A PI 44
4.2 Rotations 44
4.3 Orientation Representations 47
4.3.1 Euler Angles 47
4.3.2 Quaternions 57
Contents IX
5 Trans format ions 61
5.1 Matrices 62
5.1.1 Matrix Multiplication 63
5.1.2 MatrixT ranspose 65
5.1.3 Identity Matrix 67
5.1.4 Inverse Matrix 68
5.1.5 MEL 69
5.1.6 C++API 71
5.2 Transforming Points 72
5.2.1 MEL 72
5.2.2 C++API 74
5.3 Transforming Vectors 74
5.3.1 MEL 74
5.3.2 C++API 75
5.4 Transforming Normals 75
5.4.1 MEL 77
5.4.2 C++API 77
6 Transform N o d e s 79
6.1 Pivot Points 79
6.2 Transformation Matrices 84
6.2.1 Querying Transformation Matrices 90
6.2.2 EditingT ransformation Matrices 93
6.3 Hierarchies of Transformations 97
6.3.1 Transformation Spaces 98
6.3.2 MEL 99
6.3.3 C++API 100
~...v.. C o o r d i n a t e Frames 103
7.1 Up Axis 103
7.1.1 MEL 104
7.1.2 C++API 104
7.2 Handedness 104
7.3 Custom Coordinate Frames 106
7.3.1 C++API 109