333-D and 2-D animation--D and 2-D animation · PDF filein Cel Animation Applications of Computer Graphics in Cel Animation ... 333-D and 2-D animation--D and 2-D animation ... model

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Applications of Computer Graphics

in Cel Animation

Applications of Applications of Computer GraphicsComputer Graphics

in Cel Animationin Cel Animation

Adam FinkelsteinPrinceton University

COS 426 Spring 2003

Adam FinkelsteinAdam FinkelsteinPrinceton UniversityPrinceton University

COS 426 Spring 2003COS 426 Spring 2003

3-D and 2-D animation33--D and 2D and 2--D animationD animation

Homer 3-DHomer 3Homer 3--DD Homer 2-DHomer 2Homer 2--DD

Advantages of 3-DAdvantages of 3Advantages of 3--DD

• Complex lighting and shading• Reuse from scene to scene• Automatic in-betweening• Ease of camera motion• Realism• Texture mapping

•• Complex lighting and shadingComplex lighting and shading•• Reuse from scene to sceneReuse from scene to scene•• Automatic inAutomatic in--betweeningbetweening•• Ease of camera motionEase of camera motion•• RealismRealism•• Texture mappingTexture mapping

Advantages of 2-DAdvantages of 2Advantages of 2--DD

• Easier for traditional animators• Simple gestures convey emotion• Art form refined for 80 years

•• Easier for traditional animatorsEasier for traditional animators•• Simple gestures convey emotionSimple gestures convey emotion•• Art form refined for 80 yearsArt form refined for 80 years

Key ideaKey ideaKey idea

Use 3-D methods in 2-D animation!• Expressiveness of 2-D• Technical benefits of 3-D

Use 3Use 3--D methods in 2D methods in 2--D animation!D animation!•• Expressiveness of 2Expressiveness of 2--DD•• Technical benefits of 3Technical benefits of 3--DD

Related workRelated workRelated work

Automating cel animation pipeline[Fekete 95, Robertson 94,

Shantzis 94, Wallace 81]

Hybrid 2D/3D for cel animation[Rademacher 99, Williams 91]

Automating cel animation pipelineAutomating cel animation pipeline[[FeketeFekete 95,95, Robertson 94, Robertson 94,

ShantzisShantzis 94, 94, Wallace 81Wallace 81]]

Hybrid 2D/3D for Hybrid 2D/3D for cel cel animationanimation[[RademacherRademacher 99, Williams 9199, Williams 91]]

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Two forms of art workTwo forms of art workTwo forms of art work OverviewOverviewOverview

• Introduction• Multiperspective panoramas• Texture mapping• Shadows

•• IntroductionIntroduction•• Multiperspective Multiperspective panoramaspanoramas•• Texture mappingTexture mapping•• ShadowsShadows

Multiperspective Panoramasfor Cel Animation

Multiperspective Multiperspective PanoramasPanoramasfor for Cel Cel Animation Animation

[SIGGRAPH '98]

Daniel WoodAdam Finkelstein

John HughesCraig ThayerDavid Salesin

Daniel WoodDaniel WoodAdam FinkelsteinAdam Finkelstein

John HughesJohn HughesCraig ThayerCraig ThayerDavid David SalesinSalesin

University of WashingtonPrinceton UniversityBrown UniversityDisney Feature Animation

University of WashingtonUniversity of WashingtonPrinceton UniversityPrinceton University

Brown UniversityBrown UniversityDisney Feature Animation Disney Feature Animation

[Pinocchio, 1940][[PinocchioPinocchio, 1940], 1940]

Suggesting a moving cameraSuggesting a moving cameraSuggesting a moving camera

A multiperspective panoramaincorporates many perspectives intoa single locally coherent image.

A moving window slides across the panorama, selecting frames for the animation.

AA multiperspectivemultiperspective panoramapanoramaincorporates many perspectives intoincorporates many perspectives intoa single locally coherent image.a single locally coherent image.

A A moving windowmoving window slides across the slides across the panorama, selecting frames for the panorama, selecting frames for the animation.animation.

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ObjectiveObjectiveObjective

Given: 3D model and camera path

Create: Panorama and moving windowsuch that the 2D animationresembles the 3D animation

GivenGiven:: 3D model and camera path3D model and camera path

CreateCreate:: Panorama and moving windowPanorama and moving windowsuch that the 2D animationsuch that the 2D animationresembles the 3D animationresembles the 3D animation

1. 3-D scene and camera path1. 31. 3--D scene and camera pathD scene and camera path

2. Panorama and moving window2. Panorama and moving window2. Panorama and moving window 3. Illustrated panorama3. Illustrated panorama3. Illustrated panorama

4. Extracted frames4. Extracted frames4. Extracted frames 5. CG Elements5. CG Elements5. CG Elements

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Creating a panoramaCreating a panoramaCreating a panorama

• Take snapshots of 3D scene• Arrange snapshots in a plane• Merge snapshots into single image

•• Take snapshots of 3D sceneTake snapshots of 3D scene•• Arrange snapshots in a planeArrange snapshots in a plane•• Merge snapshots into single imageMerge snapshots into single image

Take snapshotsTake snapshotsTake snapshots

Arrange snapshotsArrange snapshotsArrange snapshots Merge snapshotsMerge snapshotsMerge snapshots

Arrange consecutive snapshotsArrange consecutive snapshotsArrange consecutive snapshots

1. Sample points from first snapshot2. Find corresponding points

on second snapshot 3. Align snapshots using a transform

1.1. Sample points from first snapshotSample points from first snapshot2.2. Find corresponding points Find corresponding points

on second snapshot on second snapshot 3.3. Align snapshots using a transformAlign snapshots using a transform

Find corresponding pointsFind corresponding pointsFind corresponding points

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Align snapshotsAlign snapshotsAlign snapshots

UntrimmedUntrimmedUntrimmed

TrimmedTrimmedTrimmed

LimitationsLimitationsLimitations

Panoramas cannot do it all(e.g., circling centerpiece of table)

Our method does not do it all(e.g., Beauty and the Beast library)

Panoramas cannot do it allPanoramas cannot do it all((e.g.e.g., circling centerpiece of table), circling centerpiece of table)

Our method does not do it allOur method does not do it all((e.g.e.g., , Beauty and the BeastBeauty and the Beast library)library)

HandHand--designeddesigned

AutomaticAutomatic

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StrengthsStrengthsStrengths

• Wide variety of camera motion• Easy experimentation• Easy CG integration • Illustrator creates detail• Hand-drawn artistic style

•• Wide variety of camera motionWide variety of camera motion•• Easy experimentationEasy experimentation•• Easy CG integration Easy CG integration •• Illustrator creates detailIllustrator creates detail•• HandHand--drawn artistic styledrawn artistic style

Texture Mapping for Cel Animation

Texture Mapping for Texture Mapping for CelCel AnimationAnimation

Wagner CorrêaRob Jensen

Craig ThayerAdam Finkelstein

Wagner Wagner CorrCorrêêaaRob Jensen Rob Jensen

Craig ThayerCraig Thayer

Adam FinkelsteinAdam Finkelstein

Princeton UniversityDisney Feature Animation

Princeton UniversityPrinceton University

Disney Feature Animation Disney Feature Animation

[SIGGRAPH '98]

Traditional cel animationTraditional cel animationTraditional cel animation Textured cel animationTextured Textured celcel animationanimation

The processThe processThe process Input of the warpInput of the warpInput of the warp

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model markermodel markermodel marker drawing markerdrawing markerdrawing marker

Marker curvesMarker curvesMarker curves Input of the warpInput of the warpInput of the warp

Output of the warp Output of the warp Output of the warp

PP QQ

A pair of marker curves A pair of marker curves A pair of marker curves

P Q

At parameter tAt parameter At parameter tt

M(t) D(t)

QPP

Many parameter values Many parameter values Many parameter values

Q

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Output of the warpOutput of the warpOutput of the warp Controlling the warpControlling the warpControlling the warp

• Weights• Viewing parameters• Extra markers

•• WeightsWeights•• Viewing parametersViewing parameters•• Extra markersExtra markers

Viewing parametersViewing parametersViewing parameters

upright upright upright

tilted tilted tilted

Extra markersExtra markersExtra markers

withwithwithwithoutwithoutwithout

VideoVideoVideo


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• Fits into current production pipeline• Little effort per frame• Avoids temporal artifacts• Combines strengths of:

2-D: gestures, timing, anticipation

3-D: texture, occlusion, foreshortening

•• Fits into current production pipelineFits into current production pipeline•• Little effort per frameLittle effort per frame•• Avoids temporal artifactsAvoids temporal artifacts•• Combines strengths of:Combines strengths of:

22--D: D: gestures, timing, anticipationgestures, timing, anticipation

33--D: D: texture, occlusion, foreshorteningtexture, occlusion, foreshortening

Shadows for Cel AnimationShadows for Shadows for

CelCel AnimationAnimation

Lena PetrovicBrian Fujito

Lance WilliamsAdam Finkelstein

Lena PetrovicLena PetrovicBrian Brian Fujito Fujito

Lance WilliamsLance Williams

Adam FinkelsteinAdam Finkelstein

Princeton UniversityDisney Feature Animation

Princeton UniversityPrinceton University

Disney Feature Animation Disney Feature Animation

[SIGGRAPH '00]

MotivationMotivationMotivation

backgroundbackgroundbackground

charactercharactercharacter

scenescenescene


backgroundbackgroundbackgroundscenescenescene



no shadowno shadowno shadow shadowshadowshadow

Shadow MattesShadow MattesShadow Mattes

cast shadows (red) - shadows on background

tone mattes (blue) - character shading

contact shadows (green) - darkness underfoot

cast shadowscast shadows (red)(red) -- shadows on backgroundshadows on background

tone mattes (blue)tone mattes (blue) -- character shadingcharacter shading

contact shadowscontact shadows (green)(green) -- darkness underfootdarkness underfoot

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Project GoalProject GoalProject Goal

backgroundbackgroundbackground


shadow mattesshadow mattesshadow mattes

Approach: 3D ModelsApproach: 3D ModelsApproach: 3D Models

2D2D2D 3D3D3D

Process: OverviewProcess: OverviewProcess: Overview

• Background Construction• Character Inflation• Depth Specification• Specifying Lights• Rendering • Compositing

•• Background ConstructionBackground Construction•• Character InflationCharacter Inflation•• Depth SpecificationDepth Specification•• Specifying LightsSpecifying Lights•• Rendering Rendering •• CompositingCompositing


• Background Construction• Character Inflation• Depth Specification• Specifying Lights• Rendering • Compositing

•• Background ConstructionBackground Construction•• Character InflationCharacter Inflation•• Depth SpecificationDepth Specification•• Specifying LightsSpecifying Lights•• Rendering Rendering •• CompositingCompositing


• Background Construction• Character Inflation• Depth Specification• Specifying Lights• Rendering• Compositing

•• Background ConstructionBackground Construction•• Character InflationCharacter Inflation•• Depth SpecificationDepth Specification•• Specifying LightsSpecifying Lights•• RenderingRendering•• CompositingCompositing




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Character InflationCharacter InflationCharacter Inflation

Inflate 3-D shapes using Teddy [Igarashi 99]Inflate 3Inflate 3--D shapes using Teddy [Igarashi 99]D shapes using Teddy [Igarashi 99]

character layercharacter layer 3D model3D model

• Two caveats: perspective & layers•• Two caveats: perspective & layersTwo caveats: perspective & layers


character layercharacter layercharacter layer 3D model3D model3D model

First layerFirst layerFirst layer


Adding a second layerAdding a second layerAdding a second layer

character layerscharacter layerscharacter layers 3D model3D model3D model


Adding a third layerAdding a third layerAdding a third layer

character layerscharacter layerscharacter layers 3D model3D model3D model

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Obtaining layersObtaining layersObtaining layers

layerslayerslayers 3D model3D model3D modelline artline artline art


camera viewcamera viewcamera view off-angle viewoffoff--angle viewangle view

Depth SpecificationDepth SpecificationDepth Specification

Adjust depth while preserving silhouette Adjust depth while preserving silhouette Adjust depth while preserving silhouette

translationtranslationtranslation shearshearshear

Depth SpecificationDepth SpecificationDepth Specification

camera viewcamera viewcamera view off-angle viewoffoff--angle viewangle view

shearshearshear

CompositingCompositingCompositing

Tone matte (blue) modifies character color.

Other mattes (red & green) darken background.

Tone matte (blue) modifies character color.Tone matte (blue) modifies character color.

Other mattes (red & green) darken background. Other mattes (red & green) darken background.

VideoVideoVideo

33 frames33 frames33 frames 16-frame cycle

1616--frame frame cyclecycle

16-frame cycle

1616--frame frame cyclecycle

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Manual creation of character layers

No aesthetic controls for:• shadow simplification• shadow stylization

Manual creation of character layers Manual creation of character layers

No aesthetic controls for:No aesthetic controls for:

•• shadow simplificationshadow simplification•• shadow stylizationshadow stylization


• Less human effort than hand-drawn

• Plausible shadows

– even in complex scenes

• Lighting effects:

– animated lights, gobos

• Freedom to experiment with lights

•• Less human effort than handLess human effort than hand--drawndrawn

•• Plausible shadowsPlausible shadows

–– even in complex sceneseven in complex scenes

•• Lighting effects: Lighting effects:

–– animated lights, gobosanimated lights, gobos

•• Freedom to experiment with lightsFreedom to experiment with lights

ConclusionsConclusionsConclusions

3D methods may be used in 2D for:• reducing human effort• achieving new effects

Lines between 3D and 2D are blurring

3D methods may be used in 2D for:3D methods may be used in 2D for:

•• reducing human effortreducing human effort•• achieving new effectsachieving new effects

Lines between 3D and 2D are blurringLines between 3D and 2D are blurring

ConclusionsConclusionsConclusions

Lines between 3D and 2D are blurringLines between 3D and 2D are blurringLines between 3D and 2D are blurring

Documents

333-D and 2-D animation--D and 2-D animation · PDF filein Cel Animation Applications of Computer Graphics in Cel Animation ... 333-D and 2-D animation--D and 2-D animation ... model