Chapter One Computer Animation

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Chapter OneComputer Animation

• Topics
• Introduction
• Definition of Computer Animation
• Traditional animation
• Computer animation
• Applications

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Definition

• Animation
• Rapid display of slightly different images create
  the illusion of motion
• Fake motion using rapidly changing images
• Early animations 16 i/s
• Current rates 25/30 i/s
• Near-perfect smoothness 70 i/s

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Definition

• Main tools
• Camera
• Drawings
• Computer-generated images

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Conventional Animation

• Make storyboard sequence of scenes
• Draw Key Frames showing characteristics or
  extreme position of characters
• Inbetweening draw intermediate frames
• Painting Fill regions with color
• Assembling put characters and objects on
  background paintings
• Filming Photograph the sequence of frames

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Story board

• One drawing for each shot in each scene
• Camera angles and transitions
• Representative illustration styles
• Verbal description of the action
• Incremental and cumulative timing
• Description of sound track

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Extremes
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Extremes and Inbetweens
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Cellophane (Cel) Animation

• Background and static objects are drawn on opaque
  paper
• Each dynamic object is drawn on a separate sheet
  of transparent cellophane
• Outline is drawn on one side
• Interior is painted on the other side
• As scene changes from one frame to the next, only
  changing objects need to be redrawn

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Definition

• Computer Animation
• Using a standard renderer to produce consecutive
  frames
• Why use computers?
• Animation is expensive
• Eg 30i/s
• 30 minutes 54000 Images
• 5 min/I, 12 hours/day, 1 year

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Definition

• Computer Animation
• Why use computers?
• Use 3D geometry
• Precision
• Realistic rendering
• Interactivity
• Simulators
• games

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Different level

• Low level individual frames
• Medium level sequences
• High level story and message
• Computer helps all three levels

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What can we animate?

• Object positions and orientations
• Shape geometry
• Shape appearance
• Lightning
• Camera
• Anything else

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Applications

• Films
• Games
• Data Visualization
• Simulators
• Virtual environments

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Applications

• Films
• Entertainment
• Toy Story, Titanic, Harry Porter, Ice Age
• Advertising
• education

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Applications

• Games
• Interactivity
• Ping-pong
• Animated creatures
• Space invaders, pac-man
• Virtual worlds
• simcity
• Multiple players in shared worlds
• Quake, parsec

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Applications

• Data Visualization
• Weather
• Flows

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Applications

• Simulators
• Design
• Robotics
• architecture
• Training
• Flight, drive, remote control
• Surgery
• Dangerous environments

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Applications

• Virtual Environments
• Virtual shopping malls
• Virtual reality

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Animation Control

• Control hierarchy
• Animation loop
• Main control techniques
• Guiding level
• Program level
• Task level

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Animation loop
database
Update scene
scripts
User input
Graphics software
Graphics hardware
Display
Display devices
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Guiding level

• The user provides coordinates directly
• Keyframe animation
• Motion capture
• The user provides coordinates indirectly
• Forward kinematics
• Inverse kinematics

Detail discussion Chapter 4
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Keyframe Animation

• The user specifies key postures at given times
• The computer interpolate inbetween

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Motion Capture

• Position are captured in real-time using sensors
• Data is mapped to an articulated body

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End of lecture 3
Questions?