Chapter 4: IMD Chapter 4: Character Animation Character Animation 1 Lecturer: Norhayati Mohd Amin

Introduction IMD Chapter 4: Character Animation Any object that is animated with expression and tries to speak to the audience through its actions is considered a character. In fact, the same techniques used to animate a dog might be used to animate a dancing bottle, a tiger or a tree. 2

3D Characters IMD Chapter 4: Character Animation A 3D character is a digital actor. Whether your character is a tin can that bounces with personality, or a photorealistic human being, the animator will need to control it easily and interactively. The specific requirements of the character's motion will dictate the complexity of the character's controls. 3

A Typical Character IMD Chapter 4: Character Animation The character’s mechanics must be convincing to an audience and the skin and clothing must also move and bend properly. This process of preparing character controls is called rigging and is used to let the animator focus on the process of animating. A fully rigged character can be quite complex as it brings together skeleton joints, surfaces, deformers, expressions, Set Driven Key, constraints, IK, BlendShapes, etc. 4

A Typical Character IMD Chapter 4: Character Animation Skeleton Joints Character Controls Constraints Selection Handles Deformers Bound Surfaces Kinematics 5

Skeleton Joints IMD Chapter 4: Character Animation Joints are used to create a framework for a character’s hierarchy. The rotation of the skeleton joints defines the motion of the character. You can use inverse kinematics for even more control. BACK 6

Character Controls IMD Chapter 4: Character Animation Using animation techniques such as Set Driven Key and expressions, you can set up attributes for controlling different parts of a character. For example, a hand joint could have attributes used to control the different finger joints. BACK 7

Constraints IMD Chapter 4: Character Animation It is possible to constrain the kinematic controls of a skeleton to objects in your scene or even simple locators. You can then animate the constraint weights to make a character pick something up or grab hold of a fixed object. BACK 8

Selection Handles IMD Chapter 4: Character Animation Selection handles give you quick access to parts of a character’s hierarchy that are to be animated. This makes it easier to work with a character after it has been rigged up for animation. BACK 9

Kinematics IMD Chapter 4: Character Animation To control your skeleton joints, you can choose from forward or inverse kinematics. Forward kinematics allows you to set the joint rotations directly. It is computation of the position and orientation of robot's end effector as a function of its joint angles. It is widely used in robotics, computer games, and animation. BACK 10

Kinematics (cont) IMD Chapter 4: Character Animation The reverse process is known as inverse kinematics. Inverse kinematics is the process of determining the parameters of a jointed flexible object (a kinematic chain) in order to achieve a desired pose – is a type of motion planning. IK allows you to position IK handles, which rotates the joints. 11

Kinematics (cont) IMD Chapter 4: Character Animation forward kinematics is when you know the joint angles and you find the coordinates inverse kinematics is when you know the coordinates and you find the joint angles. 12

Bound Surfaces IMD Chapter 4: Character Animation Surfaces of a character’s skin and clothing can be either parented or bound to the skeleton joints to make them move together. Binding places points from a surface into clusters that are then associated with particular joints. BACK 13

Deformers IMD Chapter 4: Character Animation To help the surfaces bend realistically at joints, deformers such as flexors and influence objects can be used. BACK 14

IMD Chapter 4: Character Animation 15