Expressive%20rendering%20for%20animation

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Expressive rendering for animation

• Pascal Barla
• ARTIS-GRAVIR / IMAG INRIA
• Advisers François Sillion Joëlle Thollot

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Plan

• Introduction
• First attempts Master project
• Ongoing work expressive rendering for animation
• Conclusion

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Introduction

• PR's aim optical fidelity
• Other aims
• preliminary work (i.e architecture)
• artistic sensibility (i.e paintings drawings)
• representation hypothesis
• (i.e archeology)
• Computer graphics need
• new representations

A sketch of a stadium
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Plan

• Introduction
• First attempt Master project
• Overview
• Temporal coherence
• Results
• Ongoing work expressive rendering for animation
• Conclusion

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First attempt Master project
Overview

• Following the Dynamic Canvas
• Interactive or real-time
• But focus on colors
• Image-space approach
• Color regions extraction
• Automatic simplification

A simple cube rendered with regions
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First attempt Master project
Temporal coherence

• Abrupt discontinuities in the representation
• Confidence method
• Smooth threshold on colors

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First attempt Master project
Results

• 2 videos
• Remaining problems
• color metric
• temporal coherence

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Plan

• Introduction
• First attempt Master project
• Ongoing work expressive rendering for animation
• Our goals
• Archeological applications
• System overview
• Denotation
• Composition
• Temporal coherence
• Conclusion

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Ongoing work expressive rendering for animation
Our goals

• Rendering of an animated sequence
• knowledge of all events
• User control
• off-line manipulations vs interactive
  walkthroughs
• System low-level toolbox
• high-level approach left to the user

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Archeological applications
Ongoing work expressive rendering for animation

• Traditionnal illustration watercolor lines
• Watercolor animations
• precomputed animations
• qualitative archeological movies

An illustration by J.C. Golvin
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System overview
Ongoing work expressive rendering for animation
Classic Pipeline
Our System

• Pipeline plugin
• behind a classic pipeline
• works with G-Buffers
• Saito90
• Main phases denotation composition Willats97

Two G-Buffers examples color depth
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Denotation
Ongoing work expressive rendering for animation

• Picture primitives
• points, lines and regions
• Primitives extraction
• human perception models
• Primitives generation
• i.e brush strokes

The perceptually uniform Lab color space
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Composition
Ongoing work expressive rendering for animation

• Combine extracted generated primitives
• Render with 2D techniques
• 2D Combinations ltgt 3D shaders
• Watercolor issues plasma fractals

A simple plasma fractal rendering
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Temporal Coherence
Ongoing work expressive rendering for animation

• Sudden inconsistencies (poppings flickerings)
• Our approach
• video cube adding a time axis
• frame cut into the cube along the time axis
• 3D primitives temporal coherence
• Low-level operators
• Contract/expand
• Smoothing
• Control points
• in space and/or time

The frames concatenation makes a video cube
A frame is obtained by a cut through the cube
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Conclusion

• Expressive rendering system for animation
• Image-space
• Post-processing, automatic simplification
• 2Dtime
• Temporal coherence
• User-controlled
• Video Cube operators

Work in progress
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Questions ?