Learning Maya: Character Rigging and Animation

328 Pages·2002·52.38 MB·English

by  Alias

Character Rigging
and Animation
Learning Maya: Character Rigging and Animation
© Febuary 2002, Alias|Wavefront, a division of Silicon Graphics Limited.
All rights reserved.
Authors:
Lee Graft, Bill Dwelly, Damon Riesberg, Cory Mogk
Additional Contributors:
Jason Schleifer, Kevin Lombardi, Corban Gossett, Matt Baer, Lisa Williamson
Publishing:
Bob Gundu, Deion Green, Steve Christov, Tim H. Brown, Carla Sharkey, Danielle Lamothe
This material ("Material") is copyrighted (c) 2002 Alias|Wavefront, a division ofSilicon Graphics Limited ("Alias|Wave-
front") and contains proprietary and confidential information of Alias|Wavefront. The Material is protected by national and
international intellectual property laws and treaties. All rights reserved.
THE MATERIAL IS PROVIDED "AS IS" AND ALIAS|WAVEFRONT DOES NOT WARRANT THAT THE MATERIAL
WILL MEET YOUR REQUIREMENTS OR THAT THE CONTENTS OF THE MATERIAL ARE ACCURATE OR COM-
PLETE. CONTENTS ARE SUBJECT TO CHANGE WITHOUT NOTICE. ALIAS|WAVEFRONT MAKES NO WAR-
RANTIES, EXPRESS, IMPLIED OR ARISING BY CUSTOM OR TRADE USAGE RELATING TO THE MATERIAL,
AND WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, SPECIFICALLY DISCLAIMS ANY IMPLIED
WARRANTIES OF TITLE, NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PUR-
POSE. NEITHER ALIAS|WAVEFRONT NOR ITS AFFILIATES, PARENT COMPANIES, LICENSORS OR SUPPLIERS
SHALL HAVE ANY LIABILITY IN CONTRACT, TORT OR OTHERWISE ARISING OUT OF OR IN CONNECTION
WITH THE MATERIAL.
Maya is a registered trademark of Silicon Graphics, Inc., used exclusively by Alias|Wavefront, a division of Silicon Graphics
Limited. Alias|Wavefront, Learning Maya, Maya Complete, Maya Personal Learning Edition, Maya Unlimited, MEL and
Trax are trademarks of Alias|Wavefront, a division of Silicon Graphics Limited. All other trade names or trademarks con-
tained herein are property oftheir respective owners.
ISBN: 0-9730052-3-8
Printed in Canada
10 9 8 7 6 5 4 3 2 1
CHARACTER RIGGING
AND ANIMATION
Introduction: Introducing Melvin 11
COURSE STRUCTURE
Who this class designed for
Melvin's bones
Melvin's skin
Melvin's muscles
Animating Melvin
Character optimization
THE DEPENDENCY GRAPH
Nodes
Attributes
Connections
Hierarchies
The Hypergraph
Working with hierarchies and dependencies
Parenting in the Hypergraph
Summary
Chapter 1: Skeleton setup 27
CREATING THE LOWER BODY SKELETON
LAYERS AND TEMPLATES
Creating a layer and templating geometry
BUILDING SKELETONJOINTS
Creating the leg skeletons
Creating the backbone, neck, and head
PARENTING SKELETONS
Attaching the Hips with a joint between
Summary
TABLE OF CONTENTS
Character Rigging and Animation
Chapter 2: Inverse Kinematics 41
FORWARD VS. INVERSE KINEMATICS 42
A simple leg example - Forward Kinematics 42
A simple leg example - mverse Kinematics 44
PREFERRED ANGLE 47
Working with preferred angle 47
STICKINESS 50
Setting stickiness 50
IK PRIORITY 51
Changing IK priority 51
SET DRIVEN KEY 51
Rolling cube - Set Driven Key example 52
How it works 56
Look at the Curve in the Graph Editor 56
ADDING IK TO MELVIN'S LEGS 58
Create the IK handles 58
Restricting the heel rotation 60
Build a foot control hierarchy 60
Creating a control attribute 64
Set Driven Key 64
Adding Selection handles 69
Test the setup 70
Summary 70
Chapter 3: Arms and shoulders 71
IK ROTATE PLANE SOLVER 72
Working with the IK Rotate Plane solver 72
How to avoid flipping in the arm 75
Pole Vector constraints 75
MELVIN'S ARMS 75
Creating the arm joints and setting preferred angle 76
Setting up the IK Rotate Plane solver 78
Translating the end effector of the IK chain 79
TABLE OF CONTENTS
Character Rigging and Animation
WRIST AND ELBOW CONSTRAINTS 80
Constraints 80
Working with Locators 81
Adding Pole Vector constraints to the elbows 81
Constraining the wrists to locators 82
Testing the character 83
Summary 83
Chapter 4: IK Spline solver 85
IKSplineintheback 86
Aligning local rotation axes 87
Adding the IK Spline solver 89
Test the IK Spline 91
Clusters for the IK Spline CVs 91
Creating selection handles for clusters 93
Driving the splineIK.twist attribute 94
ANIMATING MELVIN 98
Working with low resolution geometry 98
MAKING MELVIN WALK 101
Setting up for keyframing 101
Character sets 102
Subcharacter sets 102
Trax and Character sets 103
Selecting Character sets or nodes and Setting the Current Character.... 103
Creating Characters and Subcharacters 103
Animating the walk 106
Lifting the feet with Breakdown Keys 109
Adding the roll of the feet 111
Make the pelvis react to the feet 113
Animate the arms 114
TABLE OF CONTENTS
Character Rigging and Animation
GRAPH EDITOR UPDATES 115
MODIFYING FOOT ROLL 115
Adding keyframes in the Graph Editor 116
Working with the animation curves 118
Modifying Curves 120
Refining more animation curves 123
Export your Animation as a Trax Clip 123
(Optional) Procedural Animation through Expressions 125
Keeping the Pelvis between the feet 125
The expression works but what does it mean? 126
The rotation of the pelvis 127
Adding more control to the pelvis 127
Summary 128
Chapter Q: The Hand Joints 129
JOINT ORIENTATION 130
Why should you use Auto joint orient? 130
How editing joints affects joint orientation 132
How to correct flipped axes 132
When do you worry about the local rotation axis? 134
Changing Joint Orientation 135
BUILDING MELVIN'S HAND 136
Joint orientation 138
Creating the middle finger 138
Creating index and ring fingers 141
Creating the pinky finger 144
Creating the thumb 145
Jointnames 147
JOINT ORIENTATION 147
Re-AutoOrienting joints 148
Adjusting joint orientation 149
Thumb orientation 150
Setting the preferred angle 152
TABLE OF CONTENTS
Character Rigging and Animation
.153
Chapter7: The Hand Controls 155
Set Driven Key Basics 156
LOCATORS AND ADDING ATTRIBUTES 156
Creating the hand control 156
SET DRIVEN KEY TO CONTROL THE FINGERS 157
Bending fingers with Set Driven Key 157
Driving the index curl 158
Driving the finger spread 160
Driving the pinky cup 162
THE THUMB 163
Driving rotation of the thumb 164
Driving thumbPalm joint with thumbRotZ 165
Test the Controls 167
Controlling the wrist with Attributes 167
Summary 168
Chapter 8: Smooth Skinning 169
SMOOTH SKINNING MELVIN 170
EDITING WEIGHTS 173
Smooth the Hips 174
Smooth the Upper Torso (Optional) 181
PAINT WEIGHT TIPS 183
Check For Weighting From Other Influences 183
Adjust the Dropoff Rate 183
Adjust the Max Influences 184
Equalize Weighting Between Multiple Surfaces 184
ToggleHoldWeightingValues 185
Flood Values Across Surfaces 185
Prune SmallWeights 185
Chapter 9: Influence Objects 187
TABLE OF CONTENTS
Character Rigging and Animation
INFLUENCE OBJECTS 188
Adding an Elbow 188
Add a Bicep Muscle Bulge 191
Add an Influence Object for the Shoulder 196
Chapter 10: Kick the Can 199
Animation controls 200
Animation workflow and tools 20Ll
Storyboarding 200
Motion study 200
IMAGE PLANES 201
BLOCKING 203
IN-BETWEENS AND BREAKDOWNS 204
Adding in-betweens 205
Working with this character 206
Kick the Can 206
Playblast 207
FTNE-TUNiNG THE MOTION 208
Create a Trax Clip of your kick 2<W
OPTIMIZATION 211
Display optimization 212
NURBS smoothnest. 212
Fastinteraction 212
Animation preferences 212
Summary 213
Chapter11: RigidSkinning 215
BiNDSKIN 216
BindSkinexample 216
The Bind Pose 217
Detaching Skin 217
BINDSKINWTTHALATTICE 217
Binding a Lattice example 217
TABLE OF CONTENTS
Character Rigging and Animation
SET5 219
Partitions 219
SKINNING MELVlN 220
Creating a skinSets partition 220
Adding geometry to sets 221
Dividing geometry into sets 221
Creating arm and legs sets 225
Creating head and neck sets 225
Creating skeleton sets 226
Skinning with lattices and wraps 227
Creating the upper torso lattice 227
Creating the shorts wrap 228
Binding lattices and skin to joints 229
Summary 230
Chapter 12: Set Membership 231
CVWEIGHTlNG 232
Adjust cluster weights on a cylinder example 232
EDITTNG SET MEMBERSHIP 232
Tips for editing set membership 233
Editing set membership for the shirt lattice 233
Editing set membership for the shorts wrap 235
WEIGHTING LATTICE POINTS 236
Weighting the shirt lattice 236
Adjusting the weights of the shorts wrap (Optional) 237
Testing skinning with animation and poses 238
Exercise 239
Summary 239
Chapter 13: Flexors 241
Fl KXOKS 242
Lattice Flexors 242
Lattice Deformers versus Lattice Flexors 242
Creatirvgalatticcflexoronajointversusabone 243