IMD 4003: Introduction to Animation

For IMD 4003: Computer Animation, taught by Chris Joslin

Contents

1. 1. A History of Animation
   1. 1.1 What is Animation?
   2. 1.2 Early Animation
   3. 1.3 Two Categories of Conventional Animation
   4. 1.4 Two Categories of CG Motion Specification
   5. 1.5 Animation Pipeline
2. 2. Eight Principles of Computer Animation
3. 3. Four Methods for Preparing Animation
4. 4. Five Types of Animation Systems

1. A History of Animation

1.1 What is Animation?

Animation is when an animator determines how an objects moves through space and time (Ex. There are two types: Motion Pictures and Simulation)

1.2 Early Animation

Examples of early animation are Thaumatrope, Flipbook, Stop Motion and Cel Animation.

Frames and Keyframes

Frames were used first - each single image represents a frame. Keyframes are the 'important' (or key) frames of an animation. Everything in between these important frames are called 'tweens.

7 Step Sequence of Conventional Animation

1. Story is written;
2. Storyboard is laid out;
3. Detailed layout - soundtrack;
4. Keyframes are drawn;
5. 'Tweens are drawn;
6. Pencil test - trail film is made;
7. Cels are prepared and coloured.

1.3 Two Categories of Conventional Animation

1. Computer-Assisted Animation: 2D and 2.5D systems computerize traditional hand-drawn animation poses (uses interpolation).
2. Computer-Generated (CG) Animation: covers all changes that have a visual effect (such as motion dynamics, update dynamics, lighting, camera position, focus, etc.). This is very good for flexibility.
   CG is used is the entertainment industry, fine art, education, scientific visualization, et al.

1.4 Two Categories of CG Motion Specification

1. Low Level Techniques:
   • Consists more of techniques (Ex. 'tweening);
   • Animator should have a very good idea of the motion they would like to achieve;
   • Requires more input from the user.
2. High Level Techniques:
   • Algorithms are used to generate a motion using a set of rules or constraints (Ex. physically-based motion);
   • Requires less input from the user but is computationally intensive.

Motion Control Method: 1^st, models begin as geometric shapes; 2^nd, use physically-based models for realism; and 3^rd, behavioural models are used to give objects or characters individuality.

1.5 Animation Pipeline (AAR)

1. Appearance: model synthetic characters and environment, where synthetic characters are life-like forms in the physical or graphical world (Ex. robots and CG characters). This can either be an imitation of real-life forms or imaginary forms (which is more visually pleasing).
2. Action: animate physical movement, environment elements (such as camera, lighting, etc) and personality/communication. Physical movement can be Physically Feasible (life-like), Perceptually Plausible (exaggerated) or Unrealistic (extreme exaggeration).
3. Rendering: includes shading and lighting, real-time vs. not, photo-realistic vs. not.

Why Use Objective Programming? It can be very expressive for us creative artists and powerful enough to use without worrying about how to specify the details we don't care about.

2. Eight Principles of Animation (TEA SAFES)

1. Timing and Motion: the timing or speed of the motion gives meaning to the movement. This can help emphasize weight, scaling or emotion.
2. Ease-in/Ease-Out: describes the spacing of the 'tweens (uses non-linear interpolation). This is good for fluidity and naturalism.
3. Arcs: describes visual path of action from one extreme to another. This is, again, good for fluidity and naturalism.
   
   
4. Squash and Stretch: movement emphasizes rigidity by preserving the volume (similar to geometric deformation).
5. Anticipation: the preparation of an action through a reveal, indication of speed and directing the attention (Ex. In real life, amateur boxers telegraph their punches by pulling back before they punch).
6. Follow Through: termination of an action through weight and drag, initiation, and overlapping.
7. Exaggeration: exaggerate the essence of an action; helps to emphasize the action, emotion, shape or sound.
8. Secondary Action: secondary occurs directly from a primary action. This provides interest and realism. (Ex. You jump off a cliff wearing a cape. The primary action is you jumping and the secondary action is your cape waving in the wind). This technique is similar to physically-based motion.

3. Four Methods for Preparing Animation

Traditional Animation Techniques

1. Straight-Ahead: animator draws or sets up some objects one frame at a time in sequence. This is good for creativity but difficult to time and tweak.
2. Pose to Pose: similar to keyframing; animator sets up main frames and does the 'tweens later. This is good for tweaking, timing, and planning out the animation. This technique is similar to timing, easing and arcs (TEA).

Traditional Assessment

3. Staging: presenting the idea so that it is unmistakeably clear. You should be able to tell what the action is solely by the silhouette. This is similar to rendering.
4. Appeal: character has charm (personality), a pleasing design and simplicity. (Ex. Exaggerate the design, avoid symmetry, use overlapping action.)

4. Five Types of Animation Systems (PSS BR)

1. Procedural: control over motion is achieved through procedures that explicitly define the movement as a function of time.
2. Scripting Systems: animator writes a script. The system is not interactive (Ex. ASAS).
3. Stochastic: controls general features by invoking stochastic processes that generate large amounts of low-level detail (Ex. Good for particle systems).
   
   
4. Behavioural: objects are given a set of rules about how they interact with their environment. (Ex. A school of fish.)
5. Representation: the data that represents the object is animated. There are 3 types: 1) Jointed objects; 2) Soft (deformable); and 3) Morphing.