AnimationCS 551 / 651

David BroganDavid Brogan

dbrogan@cs.virginia.edudbrogan@cs.virginia.edu

David BroganDavid Brogan

dbrogan@cs.virginia.edudbrogan@cs.virginia.edu

Introduction

We are going to study how things move and the We are going to study how things move and the creation of computer graphics representations that creation of computer graphics representations that look “good enough”look “good enough”

RenderingRendering isis: mapping light sources and surfaces to a : mapping light sources and surfaces to a vector of pixel colorsvector of pixel colors

AnimationAnimation isis: mapping objects, intentions, and external : mapping objects, intentions, and external forces to a vector of new object positions / orientationsforces to a vector of new object positions / orientations

We are going to study how things move and the We are going to study how things move and the creation of computer graphics representations that creation of computer graphics representations that look “good enough”look “good enough”

RenderingRendering isis: mapping light sources and surfaces to a : mapping light sources and surfaces to a vector of pixel colorsvector of pixel colors

AnimationAnimation isis: mapping objects, intentions, and external : mapping objects, intentions, and external forces to a vector of new object positions / orientationsforces to a vector of new object positions / orientations

We will not

Develop drawing skillsDevelop drawing skills

• but we may study how others draw so we can automate the but we may study how others draw so we can automate the processprocess

Learn how to use MayaLearn how to use Maya

• but we may use Maya as a rendering toolbut we may use Maya as a rendering tool

Hone our video game or moviemaking skillsHone our video game or moviemaking skills

• but we will study how modern animation technology contributes but we will study how modern animation technology contributes to video games and what elements of moviemaking artistry to video games and what elements of moviemaking artistry (timing, camera angles, etc.) must reside in animation tools(timing, camera angles, etc.) must reside in animation tools

Develop drawing skillsDevelop drawing skills

• but we may study how others draw so we can automate the but we may study how others draw so we can automate the processprocess

Learn how to use MayaLearn how to use Maya

• but we may use Maya as a rendering toolbut we may use Maya as a rendering tool

Hone our video game or moviemaking skillsHone our video game or moviemaking skills

• but we will study how modern animation technology contributes but we will study how modern animation technology contributes to video games and what elements of moviemaking artistry to video games and what elements of moviemaking artistry (timing, camera angles, etc.) must reside in animation tools(timing, camera angles, etc.) must reside in animation tools

Study how things move

Who else does this?Who else does this?Who else does this?Who else does this?

• BiomechanistsBiomechanists

– Physics and sensorsPhysics and sensors

• ArtistsArtists

– Intuition and mind’s eyeIntuition and mind’s eye

• BiomechanistsBiomechanists

– Physics and sensorsPhysics and sensors

• ArtistsArtists

– Intuition and mind’s eyeIntuition and mind’s eye

Study how things move

We’ll investigateWe’ll investigate

• Human walking, running, dancingHuman walking, running, dancing

• Bicycle ridingBicycle riding

• Group behaviorsGroup behaviors

• Rigid body dynamicsRigid body dynamics

We’ll investigateWe’ll investigate

• Human walking, running, dancingHuman walking, running, dancing

• Bicycle ridingBicycle riding

• Group behaviorsGroup behaviors

• Rigid body dynamicsRigid body dynamics

Generate graphics that is “good enough”

Who else studies this?Who else studies this?Who else studies this?Who else studies this?

• Perceptual psychologistsPerceptual psychologists

• ArtistsArtists

• Perceptual psychologistsPerceptual psychologists

• ArtistsArtists

PicassoThe Bull (1946)

MonetLa Cathédrale de Rouen

(1894)

University of Utah

Generate graphics that is “good enough”

We’ll investigateWe’ll investigate

• Recent perceptual literature (change blindness)Recent perceptual literature (change blindness)

• Recent computer animation experiments (faking Recent computer animation experiments (faking physics)physics)

We’ll investigateWe’ll investigate

• Recent perceptual literature (change blindness)Recent perceptual literature (change blindness)

• Recent computer animation experiments (faking Recent computer animation experiments (faking physics)physics)

Completing the mapping

Bridge gap between knowledge of how Bridge gap between knowledge of how things move to how they need to be things move to how they need to be renderedrendered

• Artists use their minds and handsArtists use their minds and hands

• Computer scientists use math and programsComputer scientists use math and programs

Bridge gap between knowledge of how Bridge gap between knowledge of how things move to how they need to be things move to how they need to be renderedrendered

• Artists use their minds and handsArtists use their minds and hands

• Computer scientists use math and programsComputer scientists use math and programs

Traditional techniques

• Keyframing (Shoemake)Keyframing (Shoemake)

– Orientation reps (quaternion, euler)Orientation reps (quaternion, euler)

– Curve reps (linear, quadratic, wavelets)Curve reps (linear, quadratic, wavelets)

– Interpolation (computing arclength, Gaussian Interpolation (computing arclength, Gaussian Quadrature, SLERP)Quadrature, SLERP)

• Disney artists (Johnson)Disney artists (Johnson)

• Timing / storyboardingTiming / storyboarding

• Keyframing (Shoemake)Keyframing (Shoemake)

– Orientation reps (quaternion, euler)Orientation reps (quaternion, euler)

– Curve reps (linear, quadratic, wavelets)Curve reps (linear, quadratic, wavelets)

– Interpolation (computing arclength, Gaussian Interpolation (computing arclength, Gaussian Quadrature, SLERP)Quadrature, SLERP)

• Disney artists (Johnson)Disney artists (Johnson)

• Timing / storyboardingTiming / storyboarding

Numerical Methods

• Curve fitting (least squares)Curve fitting (least squares)

• Optimization Optimization

– Simulated annealing (Numerical Recipes)Simulated annealing (Numerical Recipes)

– SimplexSimplex

– Spacetime Constraints (Witkin & Kass)Spacetime Constraints (Witkin & Kass)

– Genetic Algorithms (Sims)Genetic Algorithms (Sims)

– Neural Networks (Grzeszczuk)Neural Networks (Grzeszczuk)

• Curve fitting (least squares)Curve fitting (least squares)

• Optimization Optimization

– Simulated annealing (Numerical Recipes)Simulated annealing (Numerical Recipes)

– SimplexSimplex

– Spacetime Constraints (Witkin & Kass)Spacetime Constraints (Witkin & Kass)

– Genetic Algorithms (Sims)Genetic Algorithms (Sims)

– Neural Networks (Grzeszczuk)Neural Networks (Grzeszczuk)

Human Motion

• Motion CaptureMotion Capture

– Retargeting (Gleicher, J. Lee, Z. Popovic, Arikan)Retargeting (Gleicher, J. Lee, Z. Popovic, Arikan)

– Blending (Rose)Blending (Rose)

– Abstraction (Unuma)Abstraction (Unuma)

• WalkingWalking

– Biomechanics (McMahon, Ruina)Biomechanics (McMahon, Ruina)

– Gait Generation (Metaxas, van de Panne, Hodgins)Gait Generation (Metaxas, van de Panne, Hodgins)

• Motion CaptureMotion Capture

– Retargeting (Gleicher, J. Lee, Z. Popovic, Arikan)Retargeting (Gleicher, J. Lee, Z. Popovic, Arikan)

– Blending (Rose)Blending (Rose)

– Abstraction (Unuma)Abstraction (Unuma)

• WalkingWalking

– Biomechanics (McMahon, Ruina)Biomechanics (McMahon, Ruina)

– Gait Generation (Metaxas, van de Panne, Hodgins)Gait Generation (Metaxas, van de Panne, Hodgins)

Physical Simulation• Rigid BodyRigid Body

– Physics for games (Hecker)Physics for games (Hecker)

– Featherstone’s MethodFeatherstone’s Method

– Constraint satisfactionConstraint satisfaction

• IntegrationIntegration

– Runge-KuttaRunge-Kutta

– EulerEuler

• Simplification (Chenney, Lin, Popovic)Simplification (Chenney, Lin, Popovic)

• Perception (O’Sullivan, Proffitt)Perception (O’Sullivan, Proffitt)

• Rigid BodyRigid Body

– Physics for games (Hecker)Physics for games (Hecker)

– Featherstone’s MethodFeatherstone’s Method

– Constraint satisfactionConstraint satisfaction

• IntegrationIntegration

– Runge-KuttaRunge-Kutta

– EulerEuler

• Simplification (Chenney, Lin, Popovic)Simplification (Chenney, Lin, Popovic)

• Perception (O’Sullivan, Proffitt)Perception (O’Sullivan, Proffitt)

Autonomous Agents

• Behaviors (Thalmann, Badler, Blumberg)Behaviors (Thalmann, Badler, Blumberg)

• Group actions (Reynolds, Brogan, Helbing)Group actions (Reynolds, Brogan, Helbing)

• Behaviors (Thalmann, Badler, Blumberg)Behaviors (Thalmann, Badler, Blumberg)

• Group actions (Reynolds, Brogan, Helbing)Group actions (Reynolds, Brogan, Helbing)

Administrivia

SyllabusSyllabus• Instructor/TA coordinatesInstructor/TA coordinates

• PrereqsPrereqs

• Reading MaterialReading Material

• Assignments Assignments

• Grading & Honor CodeGrading & Honor Code

• Topic listTopic list

SyllabusSyllabus• Instructor/TA coordinatesInstructor/TA coordinates

• PrereqsPrereqs

• Reading MaterialReading Material

• Assignments Assignments

• Grading & Honor CodeGrading & Honor Code

• Topic listTopic list

Instructor / TA Coordinates

Professor BroganProfessor Brogan

• Olsson 217Olsson 217

– 982-2211982-2211

– dbrogan@cs.virginia.edudbrogan@cs.virginia.edu

– Available in office or through email appointmentsAvailable in office or through email appointments

TA TBDTA TBD

Professor BroganProfessor Brogan

• Olsson 217Olsson 217

– 982-2211982-2211

– dbrogan@cs.virginia.edudbrogan@cs.virginia.edu

– Available in office or through email appointmentsAvailable in office or through email appointments

TA TBDTA TBD

Prerequisites

Intro to GraphicsIntro to Graphics• OpenGL skillsOpenGL skills

• User interface toolkitsUser interface toolkits

• Appreciation for rendering equationsAppreciation for rendering equations

Mathematics (familiarity with…)Mathematics (familiarity with…)• Multivariate / Differential CalculusMultivariate / Differential Calculus

• Probability / StatisticsProbability / Statistics

• Linear AlgebraLinear Algebra

AI (familiarity with…)AI (familiarity with…)

Intro to GraphicsIntro to Graphics• OpenGL skillsOpenGL skills

• User interface toolkitsUser interface toolkits

• Appreciation for rendering equationsAppreciation for rendering equations

Mathematics (familiarity with…)Mathematics (familiarity with…)• Multivariate / Differential CalculusMultivariate / Differential Calculus

• Probability / StatisticsProbability / Statistics

• Linear AlgebraLinear Algebra

AI (familiarity with…)AI (familiarity with…)

Reading Material

No textbookNo textbook

• Good ones to consult:Good ones to consult:

Lots of research papersLots of research papers

• I’ll provide background lecturesI’ll provide background lectures

• Research papers provide demonstrationsResearch papers provide demonstrations

No textbookNo textbook

• Good ones to consult:Good ones to consult:

Lots of research papersLots of research papers

• I’ll provide background lecturesI’ll provide background lectures

• Research papers provide demonstrationsResearch papers provide demonstrations

Assignments

Approximately five programming Approximately five programming assignmentsassignments

• Spacetime ConstraintsSpacetime Constraints

• Inverse KinematicsInverse Kinematics

• Motion Capture Reuse / RetargetMotion Capture Reuse / Retarget

• Rigid-body Dynamical SimulatorRigid-body Dynamical Simulator

• High-level Control SystemsHigh-level Control Systems

Approximately five programming Approximately five programming assignmentsassignments

• Spacetime ConstraintsSpacetime Constraints

• Inverse KinematicsInverse Kinematics

• Motion Capture Reuse / RetargetMotion Capture Reuse / Retarget

• Rigid-body Dynamical SimulatorRigid-body Dynamical Simulator

• High-level Control SystemsHigh-level Control Systems

Assignments

Approximately four homework assignmentsApproximately four homework assignments

• Emphasize the fundamentalsEmphasize the fundamentals

– Physical simulationPhysical simulation

– Least squaresLeast squares

– Simulated annealingSimulated annealing

Approximately four homework assignmentsApproximately four homework assignments

• Emphasize the fundamentalsEmphasize the fundamentals

– Physical simulationPhysical simulation

– Least squaresLeast squares

– Simulated annealingSimulated annealing

Assignments

Course project?Course project?

• We can talk about itWe can talk about it

Course project?Course project?

• We can talk about itWe can talk about it

Assignments

Class ParticipationClass Participation

• Due to the seminar aspect of course, participation is Due to the seminar aspect of course, participation is requiredrequired

– Presentation of a paperPresentation of a paper

– Contribution to discussionsContribution to discussions

- You’ll have to be at most classes- You’ll have to be at most classes

Class ParticipationClass Participation

• Due to the seminar aspect of course, participation is Due to the seminar aspect of course, participation is requiredrequired

– Presentation of a paperPresentation of a paper

– Contribution to discussionsContribution to discussions

- You’ll have to be at most classes- You’ll have to be at most classes

Grading

Final scale will be set upon determination of Final scale will be set upon determination of grad / undergrad ratio and class sizegrad / undergrad ratio and class size

• Emphasis is on programming assignmentsEmphasis is on programming assignments

• There will be a final (probably no midterm)There will be a final (probably no midterm)

Final scale will be set upon determination of Final scale will be set upon determination of grad / undergrad ratio and class sizegrad / undergrad ratio and class size

• Emphasis is on programming assignmentsEmphasis is on programming assignments

• There will be a final (probably no midterm)There will be a final (probably no midterm)

Honor Code

Initial Assumption (assume this as default)Initial Assumption (assume this as default)

• All code is 100% you – no web, no other peopleAll code is 100% you – no web, no other people

Relaxed Assumption Relaxed Assumption

• You can use the webYou can use the web

Relaxed AssumptionRelaxed Assumption

• You can work with othersYou can work with others

The operating assumption will be specified for The operating assumption will be specified for each assignmenteach assignment

Initial Assumption (assume this as default)Initial Assumption (assume this as default)

• All code is 100% you – no web, no other peopleAll code is 100% you – no web, no other people

Relaxed Assumption Relaxed Assumption

• You can use the webYou can use the web

Relaxed AssumptionRelaxed Assumption

• You can work with othersYou can work with others

The operating assumption will be specified for The operating assumption will be specified for each assignmenteach assignment

Perception

The only reason we’re able to have this The only reason we’re able to have this class today is because our perceptual class today is because our perceptual system is easily tricked (but it’s finicky)system is easily tricked (but it’s finicky)

Modeling perception really matters for Modeling perception really matters for computer animationcomputer animation

The only reason we’re able to have this The only reason we’re able to have this class today is because our perceptual class today is because our perceptual system is easily tricked (but it’s finicky)system is easily tricked (but it’s finicky)

Modeling perception really matters for Modeling perception really matters for computer animationcomputer animation

Perception

Positive afterimage (persistence of vision)Positive afterimage (persistence of vision)

• the visual stimulus that remains after illumination the visual stimulus that remains after illumination has changed or been removedhas changed or been removed

Motion blurMotion blur

• Persistence of vision causes an object to appear to Persistence of vision causes an object to appear to be multiple places at oncebe multiple places at once

Positive afterimage (persistence of vision)Positive afterimage (persistence of vision)

• the visual stimulus that remains after illumination the visual stimulus that remains after illumination has changed or been removedhas changed or been removed

Motion blurMotion blur

• Persistence of vision causes an object to appear to Persistence of vision causes an object to appear to be multiple places at oncebe multiple places at once

Motion Blur

Virtual camera in computer graphics Virtual camera in computer graphics usually shoots with infinitely small usually shoots with infinitely small shutter speedshutter speed

• No motion blur resultsNo motion blur results

Without motion blur, 30 fps results in fast Without motion blur, 30 fps results in fast moving objects that look like they are moving objects that look like they are strobingstrobing, or hopping, or hopping

Virtual camera in computer graphics Virtual camera in computer graphics usually shoots with infinitely small usually shoots with infinitely small shutter speedshutter speed

• No motion blur resultsNo motion blur results

Without motion blur, 30 fps results in fast Without motion blur, 30 fps results in fast moving objects that look like they are moving objects that look like they are strobingstrobing, or hopping, or hopping

What’s the rate?

Playback ratePlayback rate

• The number of samples displayed per secondThe number of samples displayed per second

Sample rateSample rate

• The number of different images per secondThe number of different images per second

Playback ratePlayback rate

• The number of samples displayed per secondThe number of samples displayed per second

Sample rateSample rate

• The number of different images per secondThe number of different images per second

Playback Playback RateRate

Sample RateSample Rate

TV CartoonTV Cartoon 3030 66

TV SitcomTV Sitcom 3030 30 (on fields)30 (on fields)

CG Lipsync CG Lipsync on filmon film

2424 1212

Perception

Computer graphics rendering can rely on four-Computer graphics rendering can rely on four-hundred years of perception research by artistshundred years of perception research by artists• The best animators have is eighty years of DisneyThe best animators have is eighty years of Disney

In 1550, after 100 years of refining the art of In 1550, after 100 years of refining the art of perspective drawing, artists were shocked to think perspective drawing, artists were shocked to think that the geometric purity of their modeled world that the geometric purity of their modeled world didn’t map to recent discoveries of the human eye. didn’t map to recent discoveries of the human eye. They couldn’t even imagine how cognition affected They couldn’t even imagine how cognition affected what one “saw.” 200 more years would pass.what one “saw.” 200 more years would pass.

Computer graphics rendering can rely on four-Computer graphics rendering can rely on four-hundred years of perception research by artistshundred years of perception research by artists• The best animators have is eighty years of DisneyThe best animators have is eighty years of Disney

In 1550, after 100 years of refining the art of In 1550, after 100 years of refining the art of perspective drawing, artists were shocked to think perspective drawing, artists were shocked to think that the geometric purity of their modeled world that the geometric purity of their modeled world didn’t map to recent discoveries of the human eye. didn’t map to recent discoveries of the human eye. They couldn’t even imagine how cognition affected They couldn’t even imagine how cognition affected what one “saw.” 200 more years would pass.what one “saw.” 200 more years would pass.

Animation timeline

Persistence of visionPersistence of vision

• Thaumotrope (1800s)Thaumotrope (1800s)

• FlipbookFlipbook

• Zoetrope (1834)Zoetrope (1834)

• Shadow puppetsShadow puppets

Persistence of visionPersistence of vision

• Thaumotrope (1800s)Thaumotrope (1800s)

• FlipbookFlipbook

• Zoetrope (1834)Zoetrope (1834)

• Shadow puppetsShadow puppets

pbsKids

Animation timeline

PhotographyPhotography

• Muybridge (1885)Muybridge (1885)

• Film projector (Edison, 1891)Film projector (Edison, 1891)

PhotographyPhotography

• Muybridge (1885)Muybridge (1885)

• Film projector (Edison, 1891)Film projector (Edison, 1891)

Animation Timeline

First AnimationFirst Animation

• 1896, Georges Melies, moving tables1896, Georges Melies, moving tables

• 1900, J. Stuart Blackton, added smoke1900, J. Stuart Blackton, added smoke

First celebrated cartoonistFirst celebrated cartoonist

• Winsor McCayWinsor McCay

• Little Nemo (1911)Little Nemo (1911)

• Gertie the Dinosaur (1914)Gertie the Dinosaur (1914)

First AnimationFirst Animation

• 1896, Georges Melies, moving tables1896, Georges Melies, moving tables

• 1900, J. Stuart Blackton, added smoke1900, J. Stuart Blackton, added smoke

First celebrated cartoonistFirst celebrated cartoonist

• Winsor McCayWinsor McCay

• Little Nemo (1911)Little Nemo (1911)

• Gertie the Dinosaur (1914)Gertie the Dinosaur (1914)

Animation Timeline

1910, Bray and Hurd1910, Bray and Hurd• Patented translucent cels (formerly celluloid was Patented translucent cels (formerly celluloid was

used, but acetate is used now) used in layers for used, but acetate is used now) used in layers for compositingcompositing

• Patented gray-scale drawings (cool!)Patented gray-scale drawings (cool!)

• Patented using pegs for Patented using pegs for registrationregistration (alignment) of (alignment) of overlaysoverlays

• Patented the use of large background drawings and Patented the use of large background drawings and panning camerapanning camera

1910, Bray and Hurd1910, Bray and Hurd• Patented translucent cels (formerly celluloid was Patented translucent cels (formerly celluloid was

used, but acetate is used now) used in layers for used, but acetate is used now) used in layers for compositingcompositing

• Patented gray-scale drawings (cool!)Patented gray-scale drawings (cool!)

• Patented using pegs for Patented using pegs for registrationregistration (alignment) of (alignment) of overlaysoverlays

• Patented the use of large background drawings and Patented the use of large background drawings and panning camerapanning camera

Bray’s Studio Produced

Max Fleischer – Betty BoopMax Fleischer – Betty Boop

Paul Terry – TerrytoonsPaul Terry – Terrytoons

George Stallings – Tom and JerryGeorge Stallings – Tom and Jerry

Walter Lantz – Woody WoodpeckerWalter Lantz – Woody Woodpecker

1915, Fleischer patented 1915, Fleischer patented rotoscopingrotoscoping• Drawing images on cells by tracing over previously recorded Drawing images on cells by tracing over previously recorded

live action (MoCap)live action (MoCap)

1920, color cartoons1920, color cartoons

Max Fleischer – Betty BoopMax Fleischer – Betty Boop

Paul Terry – TerrytoonsPaul Terry – Terrytoons

George Stallings – Tom and JerryGeorge Stallings – Tom and Jerry

Walter Lantz – Woody WoodpeckerWalter Lantz – Woody Woodpecker

1915, Fleischer patented 1915, Fleischer patented rotoscopingrotoscoping• Drawing images on cells by tracing over previously recorded Drawing images on cells by tracing over previously recorded

live action (MoCap)live action (MoCap)

1920, color cartoons1920, color cartoons

Disney

Advanced animation more than anyone elseAdvanced animation more than anyone else

• First to have sound in 1928, Steamboat WillieFirst to have sound in 1928, Steamboat Willie

• First to use storyboardsFirst to use storyboards

• First to attempt realismFirst to attempt realism

• Invented multiplane cameraInvented multiplane camera

Advanced animation more than anyone elseAdvanced animation more than anyone else

• First to have sound in 1928, Steamboat WillieFirst to have sound in 1928, Steamboat Willie

• First to use storyboardsFirst to use storyboards

• First to attempt realismFirst to attempt realism

• Invented multiplane cameraInvented multiplane camera

Multiplane Camera

Camera is mounted above multiple planesCamera is mounted above multiple planes

Each plane holds an animation celEach plane holds an animation cel

Each plane can translate freely on 3 axesEach plane can translate freely on 3 axes

What is this good for?What is this good for?

Camera is mounted above multiple planesCamera is mounted above multiple planes

Each plane holds an animation celEach plane holds an animation cel

Each plane can translate freely on 3 axesEach plane can translate freely on 3 axes

What is this good for?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 KongWillis O’Brien – King Kong

Ray Harryhausen – Mighty Joe YoungRay Harryhausen – Mighty Joe Young

Nick Park – Wallace and GrommitNick Park – Wallace and Grommit

Tim Burton – Nightmare Before ChristmasTim Burton – Nightmare Before Christmas

Willis O’Brien – King KongWillis O’Brien – King Kong

Ray Harryhausen – Mighty Joe YoungRay Harryhausen – Mighty Joe Young

Nick Park – Wallace and GrommitNick Park – Wallace and Grommit

Tim Burton – Nightmare Before ChristmasTim Burton – Nightmare Before Christmas

Animation Heritage

• 1963 – Ivan Sutherland’s (MIT) Sketchpad1963 – Ivan Sutherland’s (MIT) Sketchpad

• 1970 – Evans and Sutherland (Utah) start 1970 – Evans and Sutherland (Utah) start computer graphics program (and Co.)computer graphics program (and Co.)

• 1972 – Ed Catmull’s (Utah) animated hand and 1972 – Ed Catmull’s (Utah) animated hand and face (later co-founded Pixar)face (later co-founded Pixar)

• 1970’s – Norm Badler (Penn) Center for 1970’s – Norm Badler (Penn) Center for Modeling and Simulation Modeling and Simulation and and JackJack

• 1963 – Ivan Sutherland’s (MIT) Sketchpad1963 – Ivan Sutherland’s (MIT) Sketchpad

• 1970 – Evans and Sutherland (Utah) start 1970 – Evans and Sutherland (Utah) start computer graphics program (and Co.)computer graphics program (and Co.)

• 1972 – Ed Catmull’s (Utah) animated hand and 1972 – Ed Catmull’s (Utah) animated hand and face (later co-founded Pixar)face (later co-founded Pixar)

• 1970’s – Norm Badler (Penn) Center for 1970’s – Norm Badler (Penn) Center for Modeling and Simulation Modeling and Simulation and and JackJack

Animation Heritage

• 1970’s – New York Institute of Technology 1970’s – New York Institute of Technology (NYIT) produced Alvy Ray Smith (Cofounded (NYIT) produced Alvy Ray Smith (Cofounded Pixar and Lucasfilm) and CatmullPixar and Lucasfilm) and Catmull

• 1980’s – Daniel and Nadia Magnenant-1980’s – Daniel and Nadia Magnenant-Thalmann (Swiss Universities) become Thalmann (Swiss Universities) become European powerhousesEuropean powerhouses

• 1970’s – New York Institute of Technology 1970’s – New York Institute of Technology (NYIT) produced Alvy Ray Smith (Cofounded (NYIT) produced Alvy Ray Smith (Cofounded Pixar and Lucasfilm) and CatmullPixar and Lucasfilm) and Catmull

• 1980’s – Daniel and Nadia Magnenant-1980’s – Daniel and Nadia Magnenant-Thalmann (Swiss Universities) become Thalmann (Swiss Universities) become European powerhousesEuropean powerhouses

Animation Heritage• 1980’s – z-buffer invented, SGI founded, and 1980’s – z-buffer invented, SGI founded, and

Alias/Wavefront foundedAlias/Wavefront founded

• 1977 – 1977 – StarwarsStarwars

• 1982 – 1982 – Tron Tron (first extensive use of gfx)(first extensive use of gfx)

• 1982 – Early use of particle systems (1982 – Early use of particle systems (Star Trek Star Trek II: The Wrath of KhanII: The Wrath of Khan))

• 1984 – 1984 – The Last StarfighterThe Last Starfighter (look for the Cray (look for the Cray X-MP in credits)X-MP in credits)

• 1980’s – z-buffer invented, SGI founded, and 1980’s – z-buffer invented, SGI founded, and Alias/Wavefront foundedAlias/Wavefront founded

• 1977 – 1977 – StarwarsStarwars

• 1982 – 1982 – Tron Tron (first extensive use of gfx)(first extensive use of gfx)

• 1982 – Early use of particle systems (1982 – Early use of particle systems (Star Trek Star Trek II: The Wrath of KhanII: The Wrath of Khan))

• 1984 – 1984 – The Last StarfighterThe Last Starfighter (look for the Cray (look for the Cray X-MP in credits)X-MP in credits)

Animation Heritage• 1986 – 1986 – Young Sherlock HomesYoung Sherlock Homes (first use of (first use of

synthetic character in film) synthetic character in film)

• 1986 – First digital wire removal (1986 – First digital wire removal (Howard the Howard the DuckDuck))

• 1988 – First digital blue screen extraction 1988 – First digital blue screen extraction ((WillowWillow) )

• The AbyssThe Abyss (1989) (1989) Terminator IITerminator II (1991) (1991) CasperCasper (1995), (1995), Men in BlackMen in Black (1997) (1997)

• 1986 – 1986 – Young Sherlock HomesYoung Sherlock Homes (first use of (first use of synthetic character in film) synthetic character in film)

• 1986 – First digital wire removal (1986 – First digital wire removal (Howard the Howard the DuckDuck))

• 1988 – First digital blue screen extraction 1988 – First digital blue screen extraction ((WillowWillow) )

• The AbyssThe Abyss (1989) (1989) Terminator IITerminator II (1991) (1991) CasperCasper (1995), (1995), Men in BlackMen in Black (1997) (1997)

Animation Heritage• ILM: Jurassic Park (1993), Jumangi (1995), Mars ILM: Jurassic Park (1993), Jumangi (1995), Mars

Attacks (1996), Flubber (1997), Titanic (1999)Attacks (1996), Flubber (1997), Titanic (1999)

• Angel Studios: Lawnmower Man (1992)Angel Studios: Lawnmower Man (1992)

• PDI: Batman Returns (1995) PDI: Batman Returns (1995)

• Tippett Studio: Dragonheart (1996), Starship Troopers Tippett Studio: Dragonheart (1996), Starship Troopers (1997)(1997)

• Disney: Beauty and the Beast (1991), Lion King Disney: Beauty and the Beast (1991), Lion King (1994), Tarzan (1999)(1994), Tarzan (1999)

• Dreamworks: Antz, Prince of EgyptDreamworks: Antz, Prince of Egypt

• Pixar: Toy Story, A Bug’s Life, Monster’s Inc.Pixar: Toy Story, A Bug’s Life, Monster’s Inc.

• ILM: Jurassic Park (1993), Jumangi (1995), Mars ILM: Jurassic Park (1993), Jumangi (1995), Mars Attacks (1996), Flubber (1997), Titanic (1999)Attacks (1996), Flubber (1997), Titanic (1999)

• Angel Studios: Lawnmower Man (1992)Angel Studios: Lawnmower Man (1992)

• PDI: Batman Returns (1995) PDI: Batman Returns (1995)

• Tippett Studio: Dragonheart (1996), Starship Troopers Tippett Studio: Dragonheart (1996), Starship Troopers (1997)(1997)

• Disney: Beauty and the Beast (1991), Lion King Disney: Beauty and the Beast (1991), Lion King (1994), Tarzan (1999)(1994), Tarzan (1999)

• Dreamworks: Antz, Prince of EgyptDreamworks: Antz, Prince of Egypt

• Pixar: Toy Story, A Bug’s Life, Monster’s Inc.Pixar: Toy Story, A Bug’s Life, Monster’s Inc.

Americans are hardest workingRecent history

United Nations report from Sept 1, 2003United Nations report from Sept 1, 2003

• $/worker-year$/worker-year

– US = $60,728, Belgium (top EU) = $54,333US = $60,728, Belgium (top EU) = $54,333

• hours/worker-yearhours/worker-year

– US = Japan = 1825, EU = 1300 – 1800US = Japan = 1825, EU = 1300 – 1800

• $/worker-hour$/worker-hour

– Norway, France, Belgium, USNorway, France, Belgium, US $38 $35 $34 $32 $38 $35 $34 $32

• Why is US on top of $/worker-year?Why is US on top of $/worker-year?

– Best economies encourage widespread use of communications and Best economies encourage widespread use of communications and information technologyinformation technology

– Even though we’re fat, dumb, and happy – we don’t take month-long vacations Even though we’re fat, dumb, and happy – we don’t take month-long vacations and one-year maternity breaksand one-year maternity breaks

United Nations report from Sept 1, 2003United Nations report from Sept 1, 2003

• $/worker-year$/worker-year

– US = $60,728, Belgium (top EU) = $54,333US = $60,728, Belgium (top EU) = $54,333

• hours/worker-yearhours/worker-year

– US = Japan = 1825, EU = 1300 – 1800US = Japan = 1825, EU = 1300 – 1800

• $/worker-hour$/worker-hour

– Norway, France, Belgium, USNorway, France, Belgium, US $38 $35 $34 $32 $38 $35 $34 $32

• Why is US on top of $/worker-year?Why is US on top of $/worker-year?

– Best economies encourage widespread use of communications and Best economies encourage widespread use of communications and information technologyinformation technology

– Even though we’re fat, dumb, and happy – we don’t take month-long vacations Even though we’re fat, dumb, and happy – we don’t take month-long vacations and one-year maternity breaksand one-year maternity breaks

Let’s talk about computer animation

Must generate 30 frames per second of Must generate 30 frames per second of animation (24 fps for film)animation (24 fps for film)

Issues to consider:Issues to consider:

• Is the goal to replace or augment the artist?Is the goal to replace or augment the artist?

– What does the artist bring to the project?What does the artist bring to the project?

• Is the scene/plot fixed or responsive to user?Is the scene/plot fixed or responsive to user?

– What can we automate?What can we automate?

Must generate 30 frames per second of Must generate 30 frames per second of animation (24 fps for film)animation (24 fps for film)

Issues to consider:Issues to consider:

• Is the goal to replace or augment the artist?Is the goal to replace or augment the artist?

– What does the artist bring to the project?What does the artist bring to the project?

• Is the scene/plot fixed or responsive to user?Is the scene/plot fixed or responsive to user?

– What can we automate?What can we automate?

Animation – A broad Brush

Traditional MethodsTraditional Methods

• Cartoons, stop motionCartoons, stop motion

KeyframingKeyframing

• Digital inbetweensDigital inbetweens

Motion CaptureMotion Capture

• What you record is what you getWhat you record is what you get

SimulationSimulation

• Animate what you can model (with equations)Animate what you can model (with equations)

Traditional MethodsTraditional Methods

• Cartoons, stop motionCartoons, stop motion

KeyframingKeyframing

• Digital inbetweensDigital inbetweens

Motion CaptureMotion Capture

• What you record is what you getWhat you record is what you get

SimulationSimulation

• Animate what you can model (with equations)Animate what you can model (with equations)

Computer Animation

Keyframing

Traditional animation techniqueTraditional animation technique

Dependent on artist to generate ‘key’ Dependent on artist to generate ‘key’ framesframes

Additional, ‘inbetween’ frames are drawn Additional, ‘inbetween’ frames are drawn automatically by computerautomatically by computer

Traditional animation techniqueTraditional animation technique

Dependent on artist to generate ‘key’ Dependent on artist to generate ‘key’ framesframes

Additional, ‘inbetween’ frames are drawn Additional, ‘inbetween’ frames are drawn automatically by computerautomatically by computer

Keyframing

From “The computer in the visual arts”, Spalter, 1999

How are we going to interpolate?

Linear Interpolation

Simple, but discontinuous velocity

Nonlinear Interpolation

Smooth ball trajectory and continuous velocity, but loss of timing

Easing

Adjust the timing of the inbetween frames. Can be automated by adjusting the stepsize of parameter, t.

Style or Accuracy?

Interpolating timeInterpolating timecaptures accuracycaptures accuracyof velocityof velocity

Squash and stretchSquash and stretchreplaces motionreplaces motionblur stimuli andblur stimuli andadds life-likeadds life-likeintentintent

Interpolating timeInterpolating timecaptures accuracycaptures accuracyof velocityof velocity

Squash and stretchSquash and stretchreplaces motionreplaces motionblur stimuli andblur stimuli andadds life-likeadds life-likeintentintent

Traditional Motivation

Ease-in andEase-in andease-out is likeease-out is likesquash andsquash andstretchstretch

Can weCan weautomate theautomate theinbetweens forinbetweens forthese?these?

Ease-in andEase-in andease-out is likeease-out is likesquash andsquash andstretchstretch

Can weCan weautomate theautomate theinbetweens forinbetweens forthese?these?

“The Illusion of Life, Disney Animation”Thomas and Johnson

More squash and stretch

Anticipation and Staging

Don’t surprise theDon’t surprise theaudienceaudience

Direct their Direct their attention to what’sattention to what’simportantimportant

Don’t surprise theDon’t surprise theaudienceaudience

Direct their Direct their attention to what’sattention to what’simportantimportant

Follow Through

Audience likes to see resolution of actionAudience likes to see resolution of action

Discontinuities are unsettlingDiscontinuities are unsettling

Audience likes to see resolution of actionAudience likes to see resolution of action

Discontinuities are unsettlingDiscontinuities are unsettling

Combined

Secondary Motion

Characters should exist in a real Characters should exist in a real environmentenvironment

Extra movements should not detractExtra movements should not detract

Characters should exist in a real Characters should exist in a real environmentenvironment

Extra movements should not detractExtra movements should not detract

Interpolation

Many parameters can be interpolated to Many parameters can be interpolated to generate animationgenerate animation

Simple interpolation techniques can only Simple interpolation techniques can only generate simple inbetweensgenerate simple inbetweens

More complicated inbetweening will require More complicated inbetweening will require a more complicated model of animated a more complicated model of animated object and simulationobject and simulation

Many parameters can be interpolated to Many parameters can be interpolated to generate animationgenerate animation

Simple interpolation techniques can only Simple interpolation techniques can only generate simple inbetweensgenerate simple inbetweens

More complicated inbetweening will require More complicated inbetweening will require a more complicated model of animated a more complicated model of animated object and simulationobject and simulation

Interpolation

StrengthsStrengths

• Animator has exacting control (Woody’s face)Animator has exacting control (Woody’s face)

WeaknessesWeaknesses

• Interpolation hooks must be simple and directInterpolation hooks must be simple and direct

– Remember the problems with Euler angle interp?Remember the problems with Euler angle interp?

• Time consuming and skill intensiveTime consuming and skill intensive

• Difficult to reuse and adjustDifficult to reuse and adjust

StrengthsStrengths

• Animator has exacting control (Woody’s face)Animator has exacting control (Woody’s face)

WeaknessesWeaknesses

• Interpolation hooks must be simple and directInterpolation hooks must be simple and direct

– Remember the problems with Euler angle interp?Remember the problems with Euler angle interp?

• Time consuming and skill intensiveTime consuming and skill intensive

• Difficult to reuse and adjustDifficult to reuse and adjust

Examples

Sports video gamesSports video games

• Madden FootballMadden Football

Many movie charactersMany movie characters

• Phantom MenacePhantom Menace

CartoonsCartoons

Sports video gamesSports video games

• Madden FootballMadden Football

Many movie charactersMany movie characters

• Phantom MenacePhantom Menace

CartoonsCartoons

Motion Capture Strengths

Exactly captures the motions of the actorExactly captures the motions of the actor

• Michael Jordan’s video game character will capture Michael Jordan’s video game character will capture his stylehis style

Easy to capture dataEasy to capture data

Exactly captures the motions of the actorExactly captures the motions of the actor

• Michael Jordan’s video game character will capture Michael Jordan’s video game character will capture his stylehis style

Easy to capture dataEasy to capture data

Motion Capture Weaknesses

Noise, noise, noise!Noise, noise, noise!

Magnetic system inteferenceMagnetic system inteference

Visual system occlusionsVisual system occlusions

Mechanical system massMechanical system mass

Tethered (wireless is available now)Tethered (wireless is available now)

Noise, noise, noise!Noise, noise, noise!

Magnetic system inteferenceMagnetic system inteference

Visual system occlusionsVisual system occlusions

Mechanical system massMechanical system mass

Tethered (wireless is available now)Tethered (wireless is available now)

Motion Capture Weaknesses

Aligning motion data with CG characterAligning motion data with CG character• Limb lengthsLimb lengths

• Idealized perfect jointsIdealized perfect joints

• Foot slidingFoot sliding

Reusing motion dataReusing motion data• Difficult to scale in size (must also scale in time)Difficult to scale in size (must also scale in time)

• Changing one part of motionChanging one part of motion

Aligning motion data with CG characterAligning motion data with CG character• Limb lengthsLimb lengths

• Idealized perfect jointsIdealized perfect joints

• Foot slidingFoot sliding

Reusing motion dataReusing motion data• Difficult to scale in size (must also scale in time)Difficult to scale in size (must also scale in time)

• Changing one part of motionChanging one part of motion

Motion Capture Weaknesses

Blending segmentsBlending segments

• Motion clips are short (due to range and tethers)Motion clips are short (due to range and tethers)

• Dynamic motion generation requires blending at Dynamic motion generation requires blending at run timerun time

• Difficult to manage smooth transitionDifficult to manage smooth transition

Blending segmentsBlending segments

• Motion clips are short (due to range and tethers)Motion clips are short (due to range and tethers)

• Dynamic motion generation requires blending at Dynamic motion generation requires blending at run timerun time

• Difficult to manage smooth transitionDifficult to manage smooth transition

Procedural

www.sodaplay.com

http://jet.ro/dismount

Examples

Inanimate video game objectsInanimate video game objects

• GT Racer carsGT Racer cars

• Soapbox about why this is so coolSoapbox about why this is so cool

Special effectsSpecial effects

• Explosions, water, secondary motionExplosions, water, secondary motion

• Phantom Menace CG droids after they were cut in Phantom Menace CG droids after they were cut in halfhalf

Inanimate video game objectsInanimate video game objects

• GT Racer carsGT Racer cars

• Soapbox about why this is so coolSoapbox about why this is so cool

Special effectsSpecial effects

• Explosions, water, secondary motionExplosions, water, secondary motion

• Phantom Menace CG droids after they were cut in Phantom Menace CG droids after they were cut in halfhalf

Procedural Animation

Very general term for a technique that puts Very general term for a technique that puts more complex algorithms behind the more complex algorithms behind the scenesscenes

Technique attempts to consolidate artistic Technique attempts to consolidate artistic efforts in algorithms and heuristicsefforts in algorithms and heuristics

Allows for optimization and physical Allows for optimization and physical simulationsimulation

Very general term for a technique that puts Very general term for a technique that puts more complex algorithms behind the more complex algorithms behind the scenesscenes

Technique attempts to consolidate artistic Technique attempts to consolidate artistic efforts in algorithms and heuristicsefforts in algorithms and heuristics

Allows for optimization and physical Allows for optimization and physical simulationsimulation

Procedural Animation Strengths

Animation can be generated ‘on the fly’Animation can be generated ‘on the fly’

Dynamic response to userDynamic response to user

Write-once, use-oftenWrite-once, use-often

Algorithms provide accuracy and exhaustive Algorithms provide accuracy and exhaustive search that animators cannotsearch that animators cannot

Animation can be generated ‘on the fly’Animation can be generated ‘on the fly’

Dynamic response to userDynamic response to user

Write-once, use-oftenWrite-once, use-often

Algorithms provide accuracy and exhaustive Algorithms provide accuracy and exhaustive search that animators cannotsearch that animators cannot

Procedural Animation Weaknesses

We’re not great at boiling human skill down We’re not great at boiling human skill down to algorithmsto algorithms• How do we move when juggling?How do we move when juggling?

Difficult to generateDifficult to generate

Expensive to computeExpensive to compute

Difficult to force system to generate a Difficult to force system to generate a particular solutionparticular solution• Bicycles will fall downBicycles will fall down

We’re not great at boiling human skill down We’re not great at boiling human skill down to algorithmsto algorithms• How do we move when juggling?How do we move when juggling?

Difficult to generateDifficult to generate

Expensive to computeExpensive to compute

Difficult to force system to generate a Difficult to force system to generate a particular solutionparticular solution• Bicycles will fall downBicycles will fall down

Homework

For next week:For next week:

• Read Chris Hecker articles (all four in series) on Read Chris Hecker articles (all four in series) on physical simulationphysical simulation

Game Developer MagazineGame Developer MagazineOctober/November 1996October/November 1996

• http://www.d6.com/users/checker/pdfs/gdmphys[1-4].pdfhttp://www.d6.com/users/checker/pdfs/gdmphys[1-4].pdf

For next week:For next week:

• Read Chris Hecker articles (all four in series) on Read Chris Hecker articles (all four in series) on physical simulationphysical simulation

Game Developer MagazineGame Developer MagazineOctober/November 1996October/November 1996

• http://www.d6.com/users/checker/pdfs/gdmphys[1-4].pdfhttp://www.d6.com/users/checker/pdfs/gdmphys[1-4].pdf