CS 551851 Advanced Computer Graphics by juelz11

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									       CS 551/851
Advanced Computer Graphics


        David Brogan
            General Goals
• Learn more about graphics and
  animation
  – Read and present SIGGRAPH papers
    • Be aware of state of the art research
  – Cover much of Parent’s animation text
    • Understand fundamental techniques
  – Learn by doing – programming assignments
              Prerequisites
• Introduction to computer graphics
  – Knowledge of textbook fundamentals
• OpenGL programming
  – Use the computer as a tool to quickly build
    graphical applications
• Curiosity
  – Class participation is required and the
    assignments will be dynamic
    This course does not…
• teach how to use canned software
  – We won’t learn Maya or Photoshop
• require artistic skills
• focus on film making or animated
  cartoons
  – Though we occasionally turn to these fields
    for insight and motivation
 Let’s think about what we’ve
        learned already
• Virtual cameras
  – Transformations
  – Perspective
• Photorealism
  – Decent lighting models
  – Polygonal rendering
• Geometry algorithms
  – Line/Plane equations
  – Intersection computations
 You’re pretty smart already
Among the studies of natural causes and laws,
 it is light that most delights its students.
 Among all the great branches of
 mathematics, the certainty of its
 demonstrations pre-eminently elevates the
 minds of its investigators. Perspective,
 therefore, should be preferred above all
 man’s discourses and disciplines. In this
 subject the visual rays are elucidated by
 means and demonstrations which derive their
 glory nor only from mathematics but also from
 physics; the one is adorned equally with the
 flowers of the other.
     Leonardo da Vinci (1400’s) quoting John Pecham (1200’s)
         But we labor on…
• There are some who look at the things
  produced by nature through glass, or other
  surfaces or transparent veils. They trace
  outlines on the surface of the transparent
  medium… But such an invention is to be
  condemned in those who do not know how to
  portray things without it, no how to reason
  about nature with their minds… They are
  always poor and mean in every invention and
  in the composition of narratives, which is the
  final aim of this science
                                  Leonardo da Vinci
           Advanced topics
•   More realistic modeling and lighting
•   Non photorealistic rendering
•   Animation
•   Optimization
•   Perception
What do these things mean to
           you?
• What do you think this course should be
  about?
What do these things mean to
           you?
• Ideas from
   • Video games
   • Movie special effects
   • Computer animated films
   • Office of the future
   • Video screens everywhere
   • Ubiquitous computing
        Topics from textbook
•   Curves
•   Morphing/Warping
•   Kinematics/Inverse kinematics
•   Physical simulation
•   Particle systems
•   Implicit surfaces
      Topics from textbook
• Natural phenomena (plants, water, gas)
• Modeling and animating articulated
  characters
  – Facial animation
  – Motion capture
      Topics from SIGGRAPH
•   Evolving Virtual Creatures
•   Clouds
•   Spacetime Constraints
•   Artificial Fishes
•   Tour Into the Picture
•   Virtual Cinematographer
•   Virtual Reality
•   Others…
            Other Topics
• Movie special effects
  – The “Making Of” movies
• Traditional film making
• Traditional animation
         Potential Projects
• Build a curve editor / surface modeler
• Motion capture blending
     Potential Projects

• Plant modeling
        Potential Projects
• Particle system
• Physical simulation
  control systems
         Potential Projects
• Inverse kinematics of reaching arm
• Implement SIGGRAPH paper
  – Tour Into the Picture
  – Cloud Modeling
              Textbooks
• Rick Parent – Computer Animation

• Frank Thomas and Ollie Johnson - Disney
  Animation: The Illusion of Life
• Alan Watt and Mark Watt - Advanced
  Animation and Rendering Techniques
• Edward Dmytryk - On Film Editing
• Martin Kemp – Science of Art
• Donald Bourg – Physics for Game Developers
            Grading
Projects              40%
Midterm               15%
Final                 15%
Presentations         10%
Critiques             10%
Class Participation   10%
                 Perception
• Modeling perception really matters for
  computer animation
   – We can’t rely on four-hundred years of perception
     research by artists
   – The best we have is eighty years of Disney
• In 1550, after 100 years of refining the art of
  perspective drawing, artists were shocked to
  think that the geometric purity of their
  modeled world didn’t map to recent
  discoveries of the human eye. They couldn’t
  even imagine how cognition affected what
  one “saw.” 200 more years would pass.
                Perception
• Positive afterimage (persistence of
  vision)
  – the visual stimulus that remains after
    illumination has changed or been removed
• Motion blur
  – Persistence of vision causes an object to
    appear to be multiple places at once
                 Motion Blur
• Virtual camera in computer graphics usually
  shoots with infinitely small shutter speed
   – No motion blur results
• Without motion blur, 30 fps results in fast
  moving objects that look like they are
  strobing, or hopping
   – Would CG instantaneous snapshots produce
     motion blur if played at 300 fps?
          What’s the rate?
• Playback rate
  – The number of samples displayed per second
• Sample rate
  – The number of different images per second
                    Playback
                               Sample Rate
                      Rate
       TV Cartoon     30             6
       TV Sitcom      30       30 (on fields)
       CG Lipsync
                      24            12
         on film
        Animation Timeline
• First Animation
  – 1896, Georges Melies, moving tables
  – 1900, J. Stuart Blackton, added smoke
• First celebrated cartoonist
  – Winsor McCay
  – Little Nemo (1911)
  – Gertie the Dinosaur (1914)
        Animation Timeline
• 1910, Bray and Hurd
  – Patented translucent cels (formerly
    celluloid was used, but acetate is used
    now) used in layers for compositing
  – Patented gray-scale drawings (cool!)
  – Patented using pegs for registration
    (alignment) of overlays
  – Patented the use of large background
    drawings and panning camera
       Bray’s Studio Produced
•   Max Fleischer – Betty Boop
•   Paul Terry – Terrytoons
•   George Stallings – Tom and Jerry
•   Walter Lantz – Woody Woodpecker

• 1915, Fleischer patented rotoscoping
    – Drawing images on cells by tracing over
      previously recorded live action (MoCap)
• 1920, color cartoons
                 Disney
• Advanced animation more than anyone
  else
  – First to have sound in 1928, Steamboat
    Willie
  – First to use storyboards
  – First to attempt realism
  – Invented multiplane camera
          Multiplane Camera
• Camera is mounted above multiple
  planes
• Each plane holds an animation cel
• Each plane can translate freely on 3 axes
• What is this good for?

Zooming, moving foreground characters off camera,
parallax, prolonged shutter allows blurring some layers
(motion blur)
       Stop-motion Animation
•   Willis O’Brien – King Kong
•   Ray Harryhausen – Mighty Joe Young
•   Nick Park – Wallace and Grommit
•   Tim Burton – Nightmare Before
    Christmas

								
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