npr - 2d to 3d, painting and rendering daniel teece walt disney feature animation...
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NPR - 2D to 3D, painting NPR - 2D to 3D, painting and renderingand renderingNPR - 2D to 3D, painting NPR - 2D to 3D, painting and renderingand rendering
Daniel TeeceWalt Disney Feature Animation
daniel.teece@disney.com
Daniel TeeceWalt Disney Feature Animation
daniel.teece@disney.com
IntroductionIntroductionIntroductionIntroduction
Coming up…
• Background
• 2D and 3D brush models
• Animation problems and approaches
• Examples of NPR used in film production
• Sable
Coming up…
• Background
• 2D and 3D brush models
• Animation problems and approaches
• Examples of NPR used in film production
• Sable
NPR CharacteristicsNPR CharacteristicsNPR CharacteristicsNPR Characteristics
What defines an NPR system?• “Natural Media Emulation”
• 2D / 3D
• Interactivity / Artistic direction
• Brushes, strokes and marks
• Complications - visibility … animation!
What defines an NPR system?• “Natural Media Emulation”
• 2D / 3D
• Interactivity / Artistic direction
• Brushes, strokes and marks
• Complications - visibility … animation!
NPR Cross-sectionNPR Cross-sectionNPR Cross-sectionNPR Cross-section
3D2D
automatic
interactive
image processors
stroke renderers
2D paint systems
3D paint / renderers
NPR Cross-sectionNPR Cross-sectionNPR Cross-sectionNPR Cross-section
3D2D
automatic
interactive
Litwinowicz97
Hertzmann00
Hertzmann98 Meier96
Haeberli90 DeepCanvas
Teece98
Kalnins02
2D Strokes2D Strokes2D Strokes2D Strokes
2D paint strokes and reference images• Images in, images out
• Stamp-based, procedural or physically-based
• Haeberli’s “Paint by Numbers” [Haeberli90]
• Hertzmann’s subsequent improvements [Hertzmann98]
2D paint strokes and reference images• Images in, images out
• Stamp-based, procedural or physically-based
• Haeberli’s “Paint by Numbers” [Haeberli90]
• Hertzmann’s subsequent improvements [Hertzmann98]
Animating StrokesAnimating StrokesAnimating StrokesAnimating Strokes
Finding frame to frame coherence• Stroke placement methods cause temporal
artifacts
• Locking strokes to canvas improves coherence but can look strange
• Strokes should move smoothly, matching motion of subject
Finding frame to frame coherence• Stroke placement methods cause temporal
artifacts
• Locking strokes to canvas improves coherence but can look strange
• Strokes should move smoothly, matching motion of subject
Image Space Stroke Image Space Stroke AnimationAnimationImage Space Stroke Image Space Stroke AnimationAnimation
Optical flow techniques
• “Processing images and video for an impressionist effect” [Litwinowicz97]
• “Painterly rendering for video and interaction” [Hertzmann00]
• Strokes moved, added or removed based on frame-to-frame optical flow data
• Strokes retain two-dimensional nature
Optical flow techniques
• “Processing images and video for an impressionist effect” [Litwinowicz97]
• “Painterly rendering for video and interaction” [Hertzmann00]
• Strokes moved, added or removed based on frame-to-frame optical flow data
• Strokes retain two-dimensional nature
Brush Models - 3DBrush Models - 3DBrush Models - 3DBrush Models - 3D
Strokes and Surfaces
• Pixel (texture maps)
• Geometry (points & matrices)
• Procedure (paths & width vectors)
From [Katanics,Lappas99]
Strokes and Surfaces
• Pixel (texture maps)
• Geometry (points & matrices)
• Procedure (paths & width vectors)
From [Katanics,Lappas99]
Painterly Rendering for Animation [Meier96]Painterly Rendering for Animation [Meier96]
A 3D stroke renderer • Particles placed on geometry, based on
surface area
• Strokes placed at particle positions, with parameters driven by reference renders
• Depth sorting and layering for visibility
• Smooth stroke animation, with a painterly appearance
A 3D stroke renderer • Particles placed on geometry, based on
surface area
• Strokes placed at particle positions, with parameters driven by reference renders
• Depth sorting and layering for visibility
• Smooth stroke animation, with a painterly appearance
3D Expressive Paint3D Expressive Paint3D Expressive Paint3D Expressive Paint
A 3D interactive painting system • Strokes and marks in object space
• Developed for animating painterly imagery
• Fully interactive
• Two types of stroke - 3D geometry and screen aligned
A 3D interactive painting system • Strokes and marks in object space
• Developed for animating painterly imagery
• Fully interactive
• Two types of stroke - 3D geometry and screen aligned
3D Expressive Paint3D Expressive Paint3D Expressive Paint3D Expressive Paint
3D Strokes are painted interactively by ray-casting in to the stencil scene
3D Strokes are painted interactively by ray-casting in to the stencil scene
3D Expressive Paint3D Expressive Paint3D Expressive Paint3D Expressive Paint
• Paint order / depth order (“clump buffer”)
• Silhouettes - coherence & character [Kalnins02]
• Brush model - lighting, textures etc.
• Limited animation support (e.g. deforming surfaces)
• Border or transition strokes between surfaces (back to 2D/3D relationship)
• Paint order / depth order (“clump buffer”)
• Silhouettes - coherence & character [Kalnins02]
• Brush model - lighting, textures etc.
• Limited animation support (e.g. deforming surfaces)
• Border or transition strokes between surfaces (back to 2D/3D relationship)
DeepCanvasDeepCanvasDeepCanvasDeepCanvas
A 3D painting and rendering system • Painters interface uses Digpaint (in-house 2D
paint system)
• BG Painters use a set of reference layers prepared by TD (grey render, outlines …)
• Strokes are stored in stroke script files, and mapped on to 3D geometry
• Renderer ‘re-paints’ scene from new angle
A 3D painting and rendering system • Painters interface uses Digpaint (in-house 2D
paint system)
• BG Painters use a set of reference layers prepared by TD (grey render, outlines …)
• Strokes are stored in stroke script files, and mapped on to 3D geometry
• Renderer ‘re-paints’ scene from new angle
DeepCanvasDeepCanvasDeepCanvasDeepCanvas
A 2D/3D painting and rendering system A 2D/3D painting and rendering system
From [Katanics,Lappas99]
DeepCanvasDeepCanvasDeepCanvasDeepCanvas
Simplified stroke representation -
stroke spine and width vectors Simplified stroke representation -
stroke spine and width vectors
From [Katanics,Lappas99]
SableSableSableSable
A 2D/3D stroke renderer • Library of specifically scanned & processed
strokes
• Operates as a pipeline component with Inka
• Stroke paths can be any Inka line type
• Workflow designed to be driven by traditional animation
A 2D/3D stroke renderer • Library of specifically scanned & processed
strokes
• Operates as a pipeline component with Inka
• Stroke paths can be any Inka line type
• Workflow designed to be driven by traditional animation
SableSableSableSable
Requirements: • Match look of original artwork (stylized, flat,
few strokes, black background)
• Retain performance seen in pencil animation
• Animate strokes smoothly & efficiently
Requirements: • Match look of original artwork (stylized, flat,
few strokes, black background)
• Retain performance seen in pencil animation
• Animate strokes smoothly & efficiently
SableSableSableSable
First attempt - DeepCanvas brush• Utility to convert ink lines to stroke scripts
• All pre-written software (except converter)
• Problems achieving distinctive look
• DeepCanvas procedural brush sensitive to segment distribution
First attempt - DeepCanvas brush• Utility to convert ink lines to stroke scripts
• All pre-written software (except converter)
• Problems achieving distinctive look
• DeepCanvas procedural brush sensitive to segment distribution
SableSableSableSable
Animated non-mapped DeepCanvas strokesAnimated non-mapped DeepCanvas strokes
© Disney
SableSableSableSable
Brush model • Texture-based, extracted from example set
• Library of textures and shapes
• Stroke geometry is grown along spine curve
• Sharp twists are problematic … splitting
Brush model • Texture-based, extracted from example set
• Library of textures and shapes
• Stroke geometry is grown along spine curve
• Sharp twists are problematic … splitting
SableSableSableSable
Animation
Rigged curve set animated to match traditional animation
Animation
Rigged curve set animated to match traditional animation
© Disney
SableSableSableSable
Summary • Animate strokes smoothly & efficiently
• Able to match appearance of strokes
• Integration with other tools in pipeline
• Animators able to work with a pencil
Summary • Animate strokes smoothly & efficiently
• Able to match appearance of strokes
• Integration with other tools in pipeline
• Animators able to work with a pencil
ConclusionsConclusionsConclusionsConclusions
• Combining animation and NPR can be approached with 2D or 3D methods
• With 2D, frame-to-frame coherence can be difficult to maintain
• With 3D, some operations may detract from the painterly look
• Brush models vary, but are important
• Interaction and workflow are also important
• Combining animation and NPR can be approached with 2D or 3D methods
• With 2D, frame-to-frame coherence can be difficult to maintain
• With 3D, some operations may detract from the painterly look
• Brush models vary, but are important
• Interaction and workflow are also important
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