COMPUTER VISUALISATION AND ANIMATION

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COMPUTER VISUALISATIONAND ANIMATION

• Abdennour El Rhalibi
• Room 723
• a.elrhalibi_at_livjm.ac.uk

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Aims

• This module will explore computer animation
  techniques
• Keyframes and tweening,
• procedural animation,
• various motion control
• deformation techniques,
• techniques for animation of natural phenomena
  (particle systems, flocking, plant growth),
• collision detection and response.

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Learning Outcomes

• After completing the module the student should be
  able to
• storyboard, compose, and render or implement an
  animated sequence
• explain various animation techniques and select
  appropriate algorithms to generate motion for an
  animated sequence
• implement animation techniques using modern
  programming language
• Use of 3D Animation software tools (for example
  3DSMax) to produce motion for an animated sequence

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Prerequisites

• Familiarity with
• Vectors (dot products, cross products)
• Matrices (4x4 homogeneous transformations)
• Polygon rendering
• Basic lighting (normals, Gouraud, )
• OpenGL, Direct3D, Java3D, or equivalent
• C or Java
• Object oriented programming
• Basic physics

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Motion Specification and Control
Algorithms Procedures Inverse kinematics
Physics of rigid bodies Flexible bodies Particle
systems Flocking Autonomous Behavior
Techniques Aids to user Interpolation Path
following Keyframing Languages Morphing
Figure animation Reaching, Walking Facial
animation Clothes Hair Skin
Natural phenomena Plants Water Clouds Fire
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Course Details (Attempt)

• Course Overview, Computer Graphics Review and
  Intro/Review of Opengl
• Traditional animation techniques, Disney's
  principles to computer animation
• Key frame animation Hermite, Catmull-Rom, TCB
  Interpolation of positions and rotations Path
  animation.
• Articulated structures, Forward/Inverse
  kinematics, Character animation.
• Free form deformation and morphing Light and
  camera animation.
• Procedural models of 3D objects Fractal models
  of landscapes, L-System models of plants.
• Procedural animation Particle systems.
• Physically-based animation Dynamics of rigid
  bodies.
• Continuation of physically-based animation
  Collision detection, Responding to collisions.
• Game playing architectures User interaction for
  control of dynamic objects, Automatic camera
  control.

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Main References

• Alan Watt and Mark Watt, (1992) Animation and
  Rendering Techniques, Theory and Practice,
  Addison-Wesley, ISBN 0-201-54412-1.
• OR
• Rick Parent, (2001) Computer Animation
  Algorithms and Techniques, Morgan Kaufmann
  ISBN 1558605797.
• Frank Thomas and Ollie Johnson, (1981) Disney
  Animation The Illusion of Life Abbeville Press,
  New York. ISBN 0-89659-498-X
• Jon Mc Farland, Rob Polevoi, (2001) 3DS Max 4 In
  Depth   Coriolis Group Books ISBN 1576108694
• OR
• Ted Boardman, (2001) 3D Studio MAX 4
  Fundamentals New Riders ISBN 073571066X
• Isaac Victor Kerlow, (2000) The Art of 3-D
  Computer Animation and Imaging Van Nostrand
  Reinhold ISBN 0442018967
• Some OPENGL (e.g. References to Advances
  Computers Graphics)

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Readings
Course Textbook
Computer Animation Algorithms and
Techniques 1st Edition Rick Parent Published by
Morgan Kaufmann
Check web site suggested for recommended reading
list on Other animation books (traditional,
computer-assisted) and technical papers
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Programming Languages and Tool

• Courseworks Opengl, 3DSMAX (MaxScript)
• Tutorial Opengl, DirectX, 3DSMAX
• Labs Opengl, 3DS MAX

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Course Assessment

• 1) Coursework 1 50 Designing, Documenting and
  Implementing animation algorithms with a high
  level programming language or MaxScript.
• 2) Coursework 2 50 group work covers Project
  Using a 3D Animation software (40) individual
  paper-presentation (10).

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Computer Animation Overview
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Applications

• Special Effects (Movies, TV)
• Video Games
• Virtual Reality
• Simulation, Training, Military
• Medical
• Robotics, Animatronics
• Visualization
• Communication

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Physics Simulation

• Particles
• Rigid bodies
• Collisions, contact, stacking, rolling, sliding
• Articulated bodies
• Hinges, constraints
• Deformable bodies (solid mechanics)
• Elasticity, plasticity, viscosity
• Fracture
• Cloth

• Fluid dynamics
• Fluid flow (liquids gasses)
• Combustion (fire, smoke, explosions)
• Phase changes (melting, freezing, boiling)
• Vehicle dynamics
• Cars, boats, airplanes, helicopters, motorcycles
• Character dynamics
• Body motion, skin muscle, hair, clothing

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Character Animation

• Animation
• Motion playback
• Keyframing
• Blending, sequencing
• Motion synthesis
• Locomotion (walking, flying, swimming,
  slithering)
• Inverse kinematics
• Procedural animation
• Warping retargetting
• Physics (inverse dynamics, optimization)
• Motion input
• Motion capture ( other motion input techniques)
• Vision based capture

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Animation Process

• while (not finished)
• MoveEverything()
• DrawEverything()
• Interactive vs. Non-Interactive
• Real Time vs. Non-Real Time

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Frame Rates

• Film 24 fps
• Imax 48 fps
• NTSC TV 30 fps (interlaced)
• PAL TV 25 fps (interlaced)
• HDTV 60 fps
• Computer 60 fps

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Animation Tools

• Maya
• 3D Studio
• Lightwave
• Filmbox
• Blender
• Many more

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What is Animation?

• Series of pictures of objects/characters in
  Motion
• The principle of persistence of vision and phi
  phenomenonhas been known for some time.
• Displayed at some rate
• film 24 fps
• video 30 fps
• Still work at 10-12 fps
• Examples
• flipbooks
• stop motion (animatronics or claymation)
• traditional hand animation (cel animation)

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History

• Shadow puppets could be considered the beginnings
  of animation history
• In the early to mid 1800s there were a variety
  of inventions that took advantage of it, like the
  Zoetrope
• Character animation, drawn by hand, started in
  the early 1900s
• Felix the Cat (1919)
• Walt Disney starts in the 1930s

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Producing an Animation
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Producing an Animation
3DEM Flybys http//www.visualizationsoftware.com/3
dem/flybys.html
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Producing an Animation
Tomoyuki Nishita, Department of Information
Science, University of Tokyo http//nis-lab.is.s.u
-tokyo.ac.jp/nis/animation.html
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Producing an Animation
Ron Fedkiw, Stanford Computer Graphics
Lab http//graphics.stanford.edu/fedkiw/
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Producing an Animation
Ron Fedkiw, Stanford Computer Graphics
Lab http//graphics.stanford.edu/fedkiw/
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Producing an Animation
Ron Fedkiw, Stanford Computer Graphics
Lab http//graphics.stanford.edu/fedkiw/
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Producing an Animation
Ron Fedkiw, Stanford Computer Graphics
Lab http//graphics.stanford.edu/fedkiw/
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Producing an Animation

• Motion capture (natural noise!)

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Producing an Animation

• Film runs at 24 frames per second (fps)
• Thats 1440 pictures to create per minute
• 1800 fpm for video (30fps)
• Productions issues
• Need to stay organized for efficiency and cost
  reasons
• Need to create the frames systematically
• Artistic issues
• How to create the desired look and mood while
  conveying story?
• Artistic vision has to be converted into a
  sequence of still frames
• Not enough to get the stills right--must look
  right at full speed
• Hard to see the motion given the stills
• Hard to see the motion at the wrong frame rate

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Traditional Animation The Process

• Story board
• Sequence of drawings with descriptions
• Story-based description
• Key Frames
• Draw a few important frames as line drawings
• For example, beginning of stride, end of stride
• Motion-based description
• Inbetweens
• Draw the rest of the frames
• Painting
• Redraw onto acetate Cels, color them in

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Conventional Animation Process

• Storyboard
• Key frames drawn
• Straight ahead vs. pose-to-pose
• Intermediate frames filled in (inbetweening)
• Trial film is made (called a pencil test)
• Pencil test frames transferred to cels

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3D Animation

• 3D animation is similar to stop motion animation

King Kong (1932)
Flash Gordon (1972)
http//www.stopmotionanimation.com/
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Layered Motion

• Its often useful to have multiple layers of
  animation
• How to make an object move in front of a
  background?
• Use one layer for background, one for object
• Can have multiple animators working
  simultaneously on different layers, avoid
  redrawing and flickering
• Transparent acetate allows multiple layers
• Draw each separately
• Stack them together on a copy stand
• Transfer onto film by taking a photograph of the
  stack

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Computer-Assisted Animation

• Computerized Cel painting
• Digitize the line drawing, color it using seed
  fill
• Widely used in production (little hand painting
  any more)
• e.g. Lion King
• Cartoon Inbetweening
• Automatically interpolate between two drawings to
  produce inbetweens (morphing)
• Hard to get right
• inbetweens often dont look natural
• what are the parameters to interpolate? Not
  clear...
• not used very often

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True Computer Animation

• Generate the images by rendering a 3-D model
• Vary the parameters to produce the animation
• Brute force
• Manually set the parameters for each and every
  frame
• Computer keyframing
• Lead animators create the important frames with
  3-D
• Computer models
• Unpaid computers draw the inbetweens
• The dominant production method

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3D Animation

• Stop motion animation (Nightmare Before
  Christmas)
• 3D keyframing(Luxo Jr.)
• Performance animation and motion capture (Donkey
  Kong Country)
• Which must be done straight-ahead and which can
  be animated pose-topose?

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Digital Production Pipeline

• Story
• Visual Development
• Character Design
• Storyboards
• Scene Layout
• Modeling
• Animation
• Shading and Texturing
• Lighting
• Rendering
• Post Production

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Story

• Different types of stories
• beginning/middle/end with conflict and resolution
  (drama)
• sequences built around a situation
• Mickey Mouse
• String of Gags
• Roadrunner
• Story is the most important part of any animation
• 1 big, simple idea
• the story you can tell in 2 sentences

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Visual Development

• What look will your scenes have?
• Who are the characters and how do they look?
• Develop style
• Includes the creation of characters, environments
  (desert, swamp), props, etc.
• Involves painters, sculptors, illustrators, etc.
• Lots of drawings

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Character Design

• After story come characters
• Consists mostly of drawings, or sculptures
• body poses
• facial expressions
• key features from multiple points of view
• Note the lack of computers at this stage!

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Storyboards

• The film in outline form
• specify the key scenes
• specify the camera moves and edits
• specify character gross motion
• Typically paper and pencil sketches on individual
• Sheets taped on a wall
• Still not very many computers

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Story Boarding (from A Bugs Life)
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What makes a good storyboard?

• Does the shot sequence
• maintain continuity
• not confuse the audience
• contain variations in pacing
• Is the information clearly presented?
• Are the characters clearly portrayed?
• Is the story clear?
• Do you have the techniques necessary to pull it
  off?
• Can you do it with the time and you have?

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Scene Layout

• Design the scenes
• for example, build the room with an understanding
  of the camera pan
• create colors, textures, props
• keep in mind camera and character motion within
  the scene
• use placeholder geometry and start to design
  camera moves

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Digital Production Pipeline

• Story
• Visual Development
• Character Design
• Storyboards
• Scene Layout
• Modeling
• Animation
• Shading and Texturing
• Lighting
• Rendering
• Post Production

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Modeling

• Create geometric models of environment, props,
  characters
• Keep in mind the ultimate purpose of the model
  feature film, game, etc.
• Set up internal skeleton and animation handles
  appropriately for that characters behaviors

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Rendering

• Frames can take hours to render
• 1800 frames for a single minute of animation
• Pixar has a HUGE renderfarm

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Post Production

• Sound track sync
• Titles
• Cuts and effects (dissolves, fades, etc)

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Principles of Traditional Animation

• Introduction
• Many of the principles of traditional animation
  were developed in the 1930's at the Walt Disney
  studios. These principles were developed to make
  animation, especially character animation, more
  realistic and entertaining. These principles can
  and should be applied to 3D computer animation.
• Principles of Traditional Animation
• The following principles were developed and
  named
• Squash and Stretch - defining the rigidity and
  mass of an object by distorting its shape during
  an action
• Timing and Motion - spacing actions to define the
  weight and size of objects and the personality of
  characters
• Anticipation - the preparation for an action
• Staging - presenting an idea so that it is
  unmistakably clear
• Follow Through and Overlapping Action - the
  termination of an action and establishing its
  relationship to the next action
• Straight Ahead Action and Pose-to-Pose Action -
  The two contrasting approaches to the creation of
  movement
• Slow In and Out - the spacing of the in-between
  frames to achieve subtlety of timing and movement
  
• Arcs - the visual path of action for natural
  movement
• Exaggeration - Accentuating the essence of an
  idea via the design and the action
• Secondary Action - the action of an object
  resulting from another action
• Appeal - creating a design or an action that the
  audience enjoys watching
• Personality in character animation is the goal of
  all of the above.