Post on 24-Dec-2015
Expressive rendering for animation
Pascal Barla
ARTIS-GRAVIR / IMAG INRIA
Advisers : François Sillion & Joëlle Thollot
Plan Introduction First attempts : Master project Ongoing work : expressive rendering for animation Conclusion
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
Plan Introduction First attempt : Master project
Overview Temporal coherence Results
Ongoing work : expressive rendering for animation Conclusion
First attempt: Master project
• Following the Dynamic Canvas Interactive or real-time But focus on colors
• Image-space approach Color regions extraction Automatic simplification
A simple cube renderedwith regions
Overview
First attempt: Master project
• Abrupt discontinuities in the representation
• Confidence method Smooth threshold on colors
Temporal coherence
First attempt: Master project
• 2 videos
• Remaining problems• color metric• temporal coherence
Results
Plan Introduction First attempt : Master project Ongoing work : expressive rendering for animation
Our goals Archeological applications System overview Denotation Composition Temporal coherence
Conclusion
Ongoing work: expressive rendering for animation
• 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
Our goals
Archeological applications
• Traditionnal illustration = watercolor + lines
• Watercolor animations precomputed
animations qualitative
archeological movies An illustration by J.C. Golvin
Ongoing work: expressive rendering for animation
System overview
• “Pipeline plugin“ behind a classic pipeline works with G-Buffers
[Saito90]
• Main phases : denotation & composition [Willats97]
Classic Pipeline Our System
Two G-Buffers examples : color & depth
Ongoing work: expressive rendering for animation
Denotation• Picture primitives
points, lines and regions
• Primitives extraction human perception models
• Primitives generation i.e brush strokes
The perceptually uniform L*a*b* color space
Ongoing work: expressive rendering for animation
Composition
• Combine extracted & generated primitives
• Render with 2D techniques 2D Combinations <=> 3D
shaders
• Watercolor issues: plasma fractals A simple plasma fractal rendering
Ongoing work: expressive rendering for animation
Temporal Coherence• 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 concatenationmakes a video cube
A frame is obtained by a cut through the cube
Ongoing work: expressive rendering for animation
Conclusion• Expressive rendering system for animation
• Image-space Post-processing, automatic simplification
• 2D+time Temporal coherence
• User-controlled• Video Cube operators
Work in progress…
Questions ?