2009
Table Of Contents
- Contents
- Overview
- Maya Basics
- Polygonal Modeling
- Introduction
- Preparing for the lesson
- Lesson 1: Modeling a polygonal mesh
- Introduction
- Setting modeling preferences
- Using 2D reference images
- Creating a polygon primitive
- Modeling in shaded mode
- Model symmetry
- Selecting components by painting
- Selecting edge loops
- Editing components in the orthographic views
- Editing components in the perspective view
- Drawing a polygon
- Extruding polygon components
- Bridging between edges
- Adding polygons to a mesh
- Splitting polygon faces
- Terminating edge loops
- Deleting construction history
- Mirror copying a mesh
- Working with a smoothed mesh
- Creasing and hardening edges on a mesh
- Beyond the lesson
- NURBS Modeling
- Subdivision Surfaces
- Animation
- Introduction
- Preparing for the lessons
- Lesson 1: Keyframes and the Graph Editor
- Lesson 2: Set Driven Key
- Lesson 3: Path animation
- Lesson 4: Nonlinear animation with Trax
- Introduction
- Open the first scene for the lesson
- Creating clips with Trax
- Changing the position of clips with Trax
- Editing the animation of clips
- Reusing clips within Trax
- Soloing and muting tracks
- Scaling clips within Trax
- Open the second scene for the lesson
- Creating clips from motion capture data
- Extending the length of motion capture data
- Redirecting the motion within a clip
- Beyond the lesson
- Lesson 5: Inverse kinematics
- Introduction
- Open the scene for the lesson
- Understanding hierarchies
- Viewing hierarchies using the Hypergraph
- Creating a skeleton hierarchy
- Parenting a model into a skeleton hierarchy
- Applying IK to a skeleton hierarchy
- Creating a control object for an IK system
- Constraining an IK system
- Limiting the range of motion of an IK system
- Simplifying the display of a hierarchy
- Applying parent constraints on an IK system
- Planning an animation for an IK system
- Animating an IK system
- Beyond the lesson
- Character Setup
- Polygon Texturing
- Rendering
- Introduction
- Preparing for the lessons
- Lesson 1: Rendering a scene
- Introduction
- Open the scene for the lesson
- Creating shading materials for objects
- Refining shading materials for objects
- Maya renderers
- Rendering a single frame using IPR
- Rendering using the Maya software renderer
- Batch rendering a sequence of animation frames
- Viewing a sequence of rendered frames
- Beyond the lesson
- Lesson 2: Shading surfaces
- Lesson 3: Lights, shadows, and cameras
- Lesson 4: Global Illumination
- Lesson 5: Caustics
- Dynamics
- Painting
- Introduction
- Preparing for the lessons
- Lesson 1: Painting in 2D using Paint Effects
- Lesson 2: Painting in 3D using Paint Effects
- Introduction
- Preparing for the lessons
- Brushes and strokes
- Rendering Paint Effects strokes
- Paint Effects on 3D objects
- Creating a surface to paint on
- Painting on objects
- Using turbulence with brush stroke tubes
- Using additional preset brushes
- Mesh brushes
- Converting mesh strokes to polygons
- Modifying a converted polygonal mesh
- Beyond the lesson
- Lesson 3: Painting textures on surfaces
- Expressions
- Scripting in Maya
- Index
Forward and inverse kinematics
There are two techniques for posing a skeleton: forward kinematics and inverse
kinematics.
Forward kinematics (FK)
To pose a character with forward kinematics, you rotate each joint individually
until you get the desired positioning. For example, to move a hand to some
location, you must rotate several arm joints to reach the location.
When you animate a skeleton posed with forward kinematics, Maya
interpolates the joint rotations starting with the root joint, then the root’s
child joints, and so on down through the skeleton’s action hierarchy. Maya
proceeds forward through the action hierarchy, starting at the root joint.
Forward kinematics is intuitive for creating simple arc motions, but it’s tedious
if you are animating a complex skeleton. It’s also not intuitive for specifying
goal-directed motion. For example, to move a hand to some location, it’s not
obvious how to rotate the joints in an arm.
Inverse kinematics (IK)
With IK, you create an extra control structure, an IK handle, for certain joint
chains such as arms and legs. An IK handle lets you pose and animate an entire
joint chain by moving a single manipulator.
As you pose the IK handle, it automatically rotates all the joints in the joint
chain. For example, if you move a hand to a doorknob, the other joints in the
arm rotate to accommodate the hand’s new positioning.
IK is more intuitive than forward kinematics for goal-directed motion because
you can focus on the goal rather than on how you need to rotate each joint
to achieve that goal.
Posing and animating using inverse kinematics
Next, you create IK handles that you’ll later use to pose the arms and legs.
The next steps describe some initial setup you should perform before creating
the IK handles.
314 | Chapter 7 Character Setup