Animation CS 551 / 651 Lecture 2 Introduction Introduction.

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Animation CS 551 / 651 Lecture 2 Lecture 2 Introduction Introduction

Transcript of Animation CS 551 / 651 Lecture 2 Introduction Introduction.

Page 1: Animation CS 551 / 651 Lecture 2 Introduction Introduction.

AnimationCS 551 / 651

Lecture 2Lecture 2

IntroductionIntroduction

Lecture 2Lecture 2

IntroductionIntroduction

Page 2: Animation CS 551 / 651 Lecture 2 Introduction Introduction.

Today’s News: Americans are hardest working!

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

• $/worker: US = $60,728, Belgium (top EU) = $54,333$/worker: US = $60,728, Belgium (top EU) = $54,333

• hours/worker: US = Japan = 1825, EU = 1300 – 1800hours/worker: US = Japan = 1825, EU = 1300 – 1800

• output/worker-hour: Norway, France, Belgium, USoutput/worker-hour: Norway, France, Belgium, US $38 $35 $34 $32 $38 $35 $34 $32

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

– US economy encourages widespread use of US economy encourages widespread use of communications and information technology communications and information technology

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

• $/worker: US = $60,728, Belgium (top EU) = $54,333$/worker: US = $60,728, Belgium (top EU) = $54,333

• hours/worker: US = Japan = 1825, EU = 1300 – 1800hours/worker: US = Japan = 1825, EU = 1300 – 1800

• output/worker-hour: Norway, France, Belgium, USoutput/worker-hour: Norway, France, Belgium, US $38 $35 $34 $32 $38 $35 $34 $32

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

– US economy encourages widespread use of US economy encourages widespread use of communications and information technology communications and information technology

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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?

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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)

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Computer Animation

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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

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Keyframing

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

How are we going to interpolate?

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Linear Interpolation

Simple, but discontinuous velocity

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Nonlinear Interpolation

Smooth ball trajectory and continuous velocity, but loss of timing

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Easing

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

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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

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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

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More squash and stretch

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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

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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

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Combined

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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

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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

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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

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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

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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

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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)

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Motion Capture Weaknesses

Aligning motion data with CG characterAligning motion data with CG character

• Limb lengthsLimb lengths

• Idealized perfect jointsIdealized perfect joints

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

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

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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

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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

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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

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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

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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

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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