Interactive Animation And Modeling By Drawing - Pedagogical Applications In Medicine
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Transcript of Interactive Animation And Modeling By Drawing - Pedagogical Applications In Medicine
iMAGIS-GRAVIR / IMAG
Animation interactive et modélisation par le dessin
Applications pédagogiques en médecine
David Bourguignon
Doctorat de l’INPGSpécialité : modèles et instruments en médecine et biologie
Préparé au sein du laboratoire GRAVIRSous la direction de Marie-Paule Cani
M.C. Escher
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Burgeoning field
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Burgeoning field
•Biology and medicine are visual disciplines– Three-dimensional shapes
Frog tomography data
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Burgeoning field
•Biology and medicine are visual disciplines– Three-dimensional shapes– Dynamic phenomena
Dynamic imagingleft ventricle human heart
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Burgeoning field
•Biology and medicine are visual disciplines– Three-dimensional shapes– Dynamic phenomena
•Problems for teaching using real organisms– Practical availability
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Burgeoning field
•Biology and medicine are visual disciplines– Three-dimensional shapes– Dynamic phenomena
•Problems for teaching using real organisms– Practical availability– Practical feasibility
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Current solutions– Anatomical databases (images, 3D models)
http://www.netanatomy.com
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Current solutions– Anatomical databases (images, 3D models)– Multimedia documents
http://www.froguts.com
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Current solutions– Anatomical databases (images, 3D models)– Multimedia documents
http://www.froguts.com
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Current solutions– Anatomical databases (images, 3D models)– Multimedia documents
http://www.froguts.com
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Current solutions– Anatomical databases (images, 3D models)– Multimedia documents
•Drawbacks– No editing tools available
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Current solutions– Anatomical databases (images, 3D models)– Multimedia documents
•Drawbacks– No editing tools available– Teacher and students in observer role
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Need for truly interactive teaching tools– User-centered
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Need for truly interactive teaching tools– User-centered– Understand shape and function of organs
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Need for truly interactive teaching tools– User-centered– Understand shape and function of organs– Create, edit, animate models
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Need for truly interactive teaching tools
•Two interdisciplinary collaborations– MENRT research action “Beating heart”
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Need for truly interactive teaching tools
•Two interdisciplinary collaborations– MENRT research action “Beating heart”– Anatomy laboratory CHU Grenoble
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Need for truly interactive teaching tools
•Two interdisciplinary collaborations
•Two pedagogical scenarios– Physiological anatomy course
• Build interactive samples
• Experiment
iMAGIS-GRAVIR / IMAG
Information Technology in Teaching
•Need for truly interactive teaching tools
•Two interdisciplinary collaborations
•Two pedagogical scenarios– Physiological anatomy course– Structural anatomy course
• Draw or annotate
• Create or edit
iMAGIS-GRAVIR / IMAG
Our Contributions
•Part 1: Interactive physically based animation– Animating anisotropic elastic materials
[Bourguignon and Cani, EGCAS 2000]
•Part 2: Interaction in 3D using 2D input– Drawing in 3D [Bourguignon et al., EG 2001]– Modeling by drawing
iMAGIS-GRAVIR / IMAG
Our Contributions
•Part 1: Interactive physically based animation– Animating anisotropic elastic materials
[Bourguignon and Cani, EGCAS 2000]
•Part 2: Interaction in 3D using 2D input– Drawing in 3D [Bourguignon et al., EG 2001]– Modeling by drawing
iMAGIS-GRAVIR / IMAG
Motivation
•Manipulate interactive samples
Part 1
iMAGIS-GRAVIR / IMAG
Motivation
•Manipulate interactive samples
•Biological materials– Dynamics– Nonlinear elasticity– Anisotropy– Incompressibility
Part 1
Computer model ofcardiac geometry andmuscle fiber (McCulloch, UCSD)
iMAGIS-GRAVIR / IMAG
Motivation
•Manipulate interactive samples
•Biological materials– Dynamics– Nonlinear elasticity– Anisotropy– Incompressibility
Human liver (Epidaure, INRIA)
Part 1
iMAGIS-GRAVIR / IMAG
Motivation
•Manipulate interactive samples
•Biological materials
• Intuitively and efficiently
Part 1
iMAGIS-GRAVIR / IMAG
Previous Work
•Continuous Models– Large deformations [O’Brien and Hodgins, 1999]
Part 1
iMAGIS-GRAVIR / IMAG
Previous Work
•Continuous Models– Large deformations [O’Brien and Hodgins, 1999]– Multiresolution [Debunne et al., 2001]
Part 1
iMAGIS-GRAVIR / IMAG
Previous Work
•Continuous Models– Large deformations [O’Brien and Hodgins, 1999]– Multiresolution [Debunne et al., 2001]– Physical nonlinearities and transversal isotropy
[Picinbono et al., 2001]
Part 1
iMAGIS-GRAVIR / IMAG
Previous Work
•Continuous Models– Large deformations [O’Brien and Hodgins, 1999]– Multiresolution [Debunne et al., 2001]– Physical nonlinearities and transversal isotropy
[Picinbono et al., 2001]
•Problems– Incompressibility
Part 1
iMAGIS-GRAVIR / IMAG
Previous Work
•Continuous Models– Large deformations [O’Brien and Hodgins, 1999]– Multiresolution [Debunne et al., 2001]– Physical nonlinearities and transversal isotropy
[Picinbono et al., 2001]
•Problems– Incompressibility– Parameters setting
Part 1
iMAGIS-GRAVIR / IMAG
Previous Work
•Discrete Models– Large deformations
Part 1
iMAGIS-GRAVIR / IMAG
Previous Work
•Discrete Models– Large deformations– Physical nonlinearities [Lee et al., 1995]
Part 1
iMAGIS-GRAVIR / IMAG
Previous Work
•Discrete Models– Large deformations– Physical nonlinearities [Lee et al., 1995]
•Problems– No multiresolution [Debunne et al., 2001]
Part 1
iMAGIS-GRAVIR / IMAG
Previous Work
•Discrete Models– Large deformations– Physical nonlinearities [Lee et al., 1995]
•Problems– No multiresolution [Debunne et al., 2001]– Anisotropy [Ng and Fiume, 1997]
Part 1
iMAGIS-GRAVIR / IMAG
Previous Work
•Discrete Models– Large deformations– Physical nonlinearities [Lee et al., 1995]
•Problems– No multiresolution [Debunne et al., 2001]– Anisotropy [Ng and Fiume, 1997]– Incompressibility
Part 1
iMAGIS-GRAVIR / IMAG
Mass-Spring Systems
• Mesh geometry influences material behavior– Undesired anisotropy
– Incorrect behavior in bending
Tetrahedral mass-spring system
Part 1
iMAGIS-GRAVIR / IMAG
Mass-Spring Systems
• Mesh geometry influences material behavior– Undesired anisotropy
– Incorrect behavior in bending
Part 1
Tetrahedral mass-spring system
iMAGIS-GRAVIR / IMAG
Our Approach
•Goal– As simple and efficient as mass-spring system– Speed vs precision tradeoff– Anisotropy– Incompressibility
Part 1
iMAGIS-GRAVIR / IMAG
Our Approach
•Goal– As simple and efficient as mass-spring system– Speed vs precision tradeoff– Anisotropy– Incompressibility
•Choice– Discrete model– Uncouple forces directions and mesh geometry
[Barzel, 1992]
Part 1
iMAGIS-GRAVIR / IMAG
Our Approach
•Data: Geometry
Surface mesh
Part 1
iMAGIS-GRAVIR / IMAG
Our Approach
•Data: Geometry
Surface mesh
Part 1
Volume mesh
iMAGIS-GRAVIR / IMAG
Our Approach
•Data: Vector field
Surface mesh
Part 1
Volume mesh
Vector field
iMAGIS-GRAVIR / IMAG
Our Approach
•Elements
Surface mesh
Part 1
Volume mesh
Vector field
Barycenter
Axes of interest(mechanical characteristics)
iMAGIS-GRAVIR / IMAG
Our Approach
•Elements
Surface mesh
Part 1
Volume mesh
Vector field
Barycenter
Axes of interest(mechanical characteristics)
For each element:1. Element deformation2. Local frame deformation3. Forces applied to local frame4. Forces applied to nodes
iMAGIS-GRAVIR / IMAG
Forces Calculations
Stretch:Axial damped spring forces (each axis)
Shear:Angular spring forces(each pair of axes)
f1
I1’
I1
e1
f1’
f3
I1’
I1 e1
e3
I3
I3’f1
f1’
f3’
Part 1
iMAGIS-GRAVIR / IMAG
Volume Conservation• Soft constraint [Lee et al., 1995]
• Conserve sum of barycenter-vertices distances
fC
fB
fD
fA
Part 1
iMAGIS-GRAVIR / IMAG
Volume Conservation
•Comparison with mass-spring systems
With volume conservationforces
Mass-spring system
Without volume conservationforces
Part 1
iMAGIS-GRAVIR / IMAG
Results• Comparison with mass-spring systems
– No more undesired anisotropy
– Correct behavior in bending
Orthotropic material (as muscle fiber)Same parameters in the 3 directions
Part 1
iMAGIS-GRAVIR / IMAG
Results• Comparison with mass-spring systems
– No more undesired anisotropy
– Correct behavior in bending
Part 1
Orthotropic material (as muscle fiber)Same parameters in the 3 directions
iMAGIS-GRAVIR / IMAG
Results• Different anisotropic behaviors with same tetrahedral mesh
Horizontal
Part 1
iMAGIS-GRAVIR / IMAG
Results• Different anisotropic behaviors with same tetrahedral mesh
Diagonal
Part 1
iMAGIS-GRAVIR / IMAG
Results• Different anisotropic behaviors with same tetrahedral mesh
Part 1
Hemicircular
iMAGIS-GRAVIR / IMAG
Results• Different anisotropic behaviors with same tetrahedral mesh
Part 1
Concentric Helicoidal
iMAGIS-GRAVIR / IMAG
Results• Different anisotropic behaviors with same tetrahedral mesh
Part 1
Concentric Helicoidal (top view)
iMAGIS-GRAVIR / IMAG
Results• Different anisotropic behaviors with same tetrahedral mesh
Part 1
Random
iMAGIS-GRAVIR / IMAG
Validations
• Emerging behavior [Boux de Casson, 2000]– Define a behavior at the element level
– Measure the emerging behavior at the object level
Part 1
iMAGIS-GRAVIR / IMAG
Validations
• Emerging behaviorObject level behavior
Part 1
f1
I1’
I1
e1
f1’
Element level behavior (data points fit) +
iMAGIS-GRAVIR / IMAG
Validations
• Multiresolution behavior [Debunne, 2000]
Part 1
iMAGIS-GRAVIR / IMAG
Validations
• Multiresolution behavior [Debunne, 2000]
Mass-spring system Our model
Part 1
iMAGIS-GRAVIR / IMAG
Conclusion and Future Work
•Conclusion: Pedagogical application– Build interactive samples of biological materials
• Nonlinear, anisotropic behaviors
• Soft constraint for volume conservation
• Efficient
Part 1
iMAGIS-GRAVIR / IMAG
Conclusion and Future Work
•Conclusion: Pedagogical application– Build interactive samples of biological materials
• Nonlinear, anisotropic behaviors
• Soft constraint for volume conservation
• Efficient
– Experiment by varying model parameters• Intuitive system image [Norman, 1988]
Part 1
iMAGIS-GRAVIR / IMAG
Conclusion and Future Work
•Conclusion: Pedagogical application
•Future work: “Animated sketches”– Draw sample
Part 1
iMAGIS-GRAVIR / IMAG
Conclusion and Future Work
•Conclusion: Pedagogical application
•Future work: “Animated sketches”– Draw sample– Specify parameters by drawing
Part 1
iMAGIS-GRAVIR / IMAG
Conclusion and Future Work
•Conclusion: Pedagogical application
•Future work: “Animated sketches”– Draw sample– Specify parameters by drawing
Animate!
Part 1
iMAGIS-GRAVIR / IMAG
Our Contributions
•Part 1: Interactive physically based animation– Animating anisotropic elastic materials
[Bourguignon and Cani, EGCAS 2000]
•Part 2: Interaction in 3D using 2D input– Drawing in 3D [Bourguignon et al., EG 2001]– Modeling by drawing
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Most people draw– Writing alternative
• Faster
• More convenient
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Most people draw– Writing alternative– Minimal tool set
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Most people draw– Writing alternative– Minimal tool set– Since kindergarten
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Most people draw
•Few people sculpt– Materials difficult to handle
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Most people draw
•Few people sculpt– Materials difficult to handle– Simpler with computer ?
• Scanning
• Modeling
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Most people draw
•Few people sculpt
•Drawing application: Teaching– Example: Pr. Jean-Paul Chirossel, anatomy
laboratory CHU Grenoble
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Drawing characteristics– Visual abstraction
Human heart
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Drawing characteristics– Visual abstraction– Indication of uncertainty
Leonardo da Vinci
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Drawing characteristics– Visual abstraction– Indication of uncertainty– Limitation to single viewpoint
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Drawing characteristics– Visual abstraction– Indication of uncertainty– Limitation to single viewpoint
•Problems– Drawing with multiple viewpoints
Part 2
iMAGIS-GRAVIR / IMAG
Motivation
•Drawing characteristics– Visual abstraction– Indication of uncertainty– Limitation to single viewpoint
•Problems– Drawing with multiple viewpoints– Modeling by drawing
Part 2
iMAGIS-GRAVIR / IMAG
Our Contributions
•Part 1: Interactive physically based animation– Animating anisotropic elastic materials
[Bourguignon and Cani, EGCAS 2000]
•Part 2: Interaction in 3D using 2D input– Drawing in 3D [Bourguignon et al., EG 2001]– Modeling by drawing
Part 2.1
iMAGIS-GRAVIR / IMAG
Previous Work
•2D-to-3D drawing: 3D Strokes– Input stroke and its shadow [Cohen et al., 1999]
• 3D curves design, no drawing
Part 2.1
iMAGIS-GRAVIR / IMAG
Previous Work
•2D-to-3D drawing: 3D Strokes– Input stroke and its shadow [Cohen et al., 1999]– Deep canvas [Disney, 1999]
• Need a 3D model
Part 2.1
iMAGIS-GRAVIR / IMAG
Previous Work
•2D-to-3D drawing: 3D Strokes– Input stroke and its shadow [Cohen et al., 1999]– Deep canvas [Disney, 1999]– Billboard, terrain, etc., stroke [Cohen et al., 2000]
• Drawing modes adapted to landscaping only
Part 2.1
iMAGIS-GRAVIR / IMAG
Previous Work
•2D-to-3D drawing: 3D Strokes
•2D-to-3D drawing: 3D Objects– Reconstruction [Lipson and Shpitalni, 1996]
• No free-form drawing
Part 2.1
iMAGIS-GRAVIR / IMAG
Previous Work
•2D-to-3D drawing: 3D Strokes
•2D-to-3D drawing: 3D Objects– Reconstruction [Lipson and Shpitalni, 1996]– Sketching interface [Igarashi et al., 1999]
• Closed strokes only
Part 2.1
iMAGIS-GRAVIR / IMAG
Our Approach
•Drawing in 3D– Augment strokes to true 3D entities
• Line stroke: Space curve (view-independent)
Eye
Edgar Degas
Part 2.1
iMAGIS-GRAVIR / IMAG
Our Approach
•Drawing in 3D– Augment strokes to true 3D entities
• Line stroke: Space curve (view-independent)
• Silhouette stroke: Surface contour (view-dependent)
Back
Edgar Degas
Part 2.1
iMAGIS-GRAVIR / IMAG
Our Approach
•Drawing in 3D– Augment strokes to true 3D entities– Annotation of existing 3D models
Part 2.1
iMAGIS-GRAVIR / IMAG
Our Approach
•Drawing in 3D– Augment strokes to true 3D entities– Annotation of existing 3D models– Illustration in 3D
Part 2.1
iMAGIS-GRAVIR / IMAG
Our Approach
•Drawing in 3D
•Choices– Represent line stroke as space curve
Part 2.1
iMAGIS-GRAVIR / IMAG
Our Approach
•Drawing in 3D
•Choices– Represent line stroke as space curve– Represent silhouette stroke using local surface
• Infer local surface from user input
• New silhouette from new viewpoint
Part 2.1
iMAGIS-GRAVIR / IMAG
Silhouette Stroke
• Infer local surface from user input– Simplest: same local curvature in 3D as in 2D
Part 2.1
iMAGIS-GRAVIR / IMAG
Silhouette Stroke
• Infer local surface from user input– Simplest: same local curvature in 3D as in 2D– Modulate width as if fitting circles along curve
Part 2.1
iMAGIS-GRAVIR / IMAG
Silhouette Stroke
• Infer local surface from user input– Simplest: same local curvature in 3D as in 2D– Modulate width as if fitting circles along curve– Resulting surface
Part 2.1
iMAGIS-GRAVIR / IMAG
Silhouette Stroke
•New silhouette from new viewpoint– Approximate silhouette
Part 2.1
iMAGIS-GRAVIR / IMAG
Silhouette Stroke
•New silhouette from new viewpoint– Approximate silhouette– Represent uncertainty away from viewpoint
Part 2.1
iMAGIS-GRAVIR / IMAG
Silhouette Stroke
•New silhouette from new viewpoint– Approximate silhouette– Represent uncertainty away from viewpoint– Manage occlusion with background color
Part 2.1
iMAGIS-GRAVIR / IMAG
Interface for Drawing
•Two drawing modes– In empty space
Part 2.1
iMAGIS-GRAVIR / IMAG
Interface for Drawing
•Two drawing modes– In empty space– Relatively to other objects
Part 2.1
iMAGIS-GRAVIR / IMAG
Interface for Drawing
•Video
Part 2.1
iMAGIS-GRAVIR / IMAG
Applications
•Annotation
Part 2.1
iMAGIS-GRAVIR / IMAG
Applications
• Illustration
Part 2.1
iMAGIS-GRAVIR / IMAG
Conclusion
•System for drawing in 3D– View-dependent strokes
Part 2.1
iMAGIS-GRAVIR / IMAG
Conclusion
•System for drawing in 3D– View-dependent strokes– Useful for drawing simple scenes in 3D
Part 2.1
iMAGIS-GRAVIR / IMAG
Conclusion
•System for drawing in 3D– View-dependent strokes– Useful for drawing simple scenes in 3D– Useful for annotations
Part 2.1
iMAGIS-GRAVIR / IMAG
Conclusion
•System for drawing in 3D
•Limitations– Switching between stroke types
Part 2.1
iMAGIS-GRAVIR / IMAG
Conclusion
•System for drawing in 3D
•Limitations– Switching between stroke types– Plane positioning can be tedious
Part 2.1
iMAGIS-GRAVIR / IMAG
Our Contributions
•Part 1: Interactive physically based animation– Animating anisotropic elastic materials
[Bourguignon and Cani, EGCAS 2000]
•Part 2: Interaction in 3D using 2D input– Drawing in 3D [Bourguignon et al., EG 2001]– Modeling by drawing
Part 2.2
iMAGIS-GRAVIR / IMAG
Motivation
• Input: Just plain strokes…– Silhouette, sharp features ?– Texture, shading ?– Open, closed, self-intersecting ?
Part 2.2
iMAGIS-GRAVIR / IMAG
Motivation
• Input: Just plain strokes…
•Output: Manifold polyhedral surface
Part 2.2
iMAGIS-GRAVIR / IMAG
Motivation
• Input: Just plain strokes…
•Output: Manifold polyhedral surface
•Pen-and-paper for sculptors– Painter and sculptor shading
Michelangelo BuonarrotiRembrandt van Rijn
Part 2.2
iMAGIS-GRAVIR / IMAG
Previous Work•Painting depth as luminance [Williams, 1990]
Part 2.2
+
iMAGIS-GRAVIR / IMAG
Previous Work•Silhouette inflation [Williams, 1991]
Part 2.2
iMAGIS-GRAVIR / IMAG
Previous Work•Editing gradient by shading [van Overveld, 1996]
Part 2.2
iMAGIS-GRAVIR / IMAG
Previous Work•Bump map inference [Johnston, 2002]
Part 2.2
iMAGIS-GRAVIR / IMAG
Previous Work•Direct manipulation interface
Artisan [Alias|wavefront, 2002]
ZBrush [Pixologic, 2002]
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D
•Overview
Strokes2Ddiscontinuous
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D
•Overview
Strokes
Geometry
2Ddiscontinuous
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D
•Overview
Strokes
Geometry Constrained triangulation
2Ddiscontinuous
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D
•Overview
Strokes
Geometry Constrained triangulation
Non-convex hull
2Ddiscontinuous
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D
•Overview
Strokes
Geometry
Image
Constrained triangulation
Non-convex hull
2Ddiscontinuous
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D
•Overview
Strokes
Geometry
Image
Constrained triangulation
Non-convex hull
Height field
2Ddiscontinuous
2.5Dcontinuous
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D•Find a non-convex hull
– Original drawing (polylines)
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D•Find a non-convex hull
– Original drawing (polylines)– Constrained Delaunay triangulation
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D•Find a non-convex hull
– Original drawing (polylines)– Constrained Delaunay triangulation– Non-convex hull [Watson, 1997]
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D•Hole marks
– In comics books production
Stone #3, Avalon Studios
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D•Hole marks
– In comics books production– In our system
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D• Infer a height field
– Large features have large inflations
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D• Infer a height field
– Large features have large inflations– Use geometry information to build it
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D• Infer a height field
– Large features have large inflations– Use geometry information to build it– Use texture information to modulate it
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D• Infer a height field: First step
– Euclidean distance transform
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D• Infer a height field: First step
– Mapping to unit sphere [Oh et al., 2001]
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D• Infer a height field: First step
– Adaptive low pass filter [Williams, 1991]
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D• Infer a height field: Second step
– Use same filter for image
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D• Infer a height field: Third step
– Use previous height field as matte for image
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D• Infer a height field: Result
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D
•Fast polygonal height field approximation [Garland and Heckbert, 1995]
Part 2.2
iMAGIS-GRAVIR / IMAG
From 2D to 2.5D
•Result: Manifold polyhedral surface
Part 2.2
iMAGIS-GRAVIR / IMAG
Results
•A simple sketch of a human heart
iMAGIS-GRAVIR / IMAG
Conclusion
•System for modeling by drawing– Plain strokes as input– Manifold polyhedral surface as output– Using sculptor shading convention
Part 2.2
iMAGIS-GRAVIR / IMAG
Conclusion
•System for modeling by drawing– Plain strokes as input– Manifold polyhedral surface as output– Using sculptor shading convention
•Limited to a single viewpoint
Part 2.2
iMAGIS-GRAVIR / IMAG
Future Work
•From 2.5D to 3D: Iterative modeling process
Modeling by drawing
Changing viewpoint
Part 2.2
iMAGIS-GRAVIR / IMAG
Future Work
•Relief metaphor– From low to high relief– From painting to sculpture
Fourth century B.C.
First century B.C.
Fifteenth century
Part 2.2
iMAGIS-GRAVIR / IMAG
General Conclusion
•Animation of anisotropic material– Intuitive– Efficient
iMAGIS-GRAVIR / IMAG
General Conclusion
•Animation of anisotropic material
•Three-dimensional drawing system– Use drawing characteristics– Good geometric detail vs modeling speed tradeoff
iMAGIS-GRAVIR / IMAG
General Conclusion
•Animation of anisotropic material
•Three-dimensional drawing system
•Modeling by drawing from a single viewpoint
iMAGIS-GRAVIR / IMAG
General Future Work
•Evaluation according to ergonomics methods
•“Drawing as a front-end to everything” [Gross and Do, 1996]
iMAGIS-GRAVIR / IMAG
Merci de votre attention
iMAGIS-GRAVIR / IMAG