Transcript CS 551/851 Advanced Computer Graphics David Brogan General Goals • Learn more about graphics and animation – Read and present SIGGRAPH papers • Be aware of.

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
Rate
Sample Rate
TV Cartoon
30
6
TV Sitcom
30
30 (on fields)
CG Lipsync
on film
24
12
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