Relief: A Modeling By Drawing Tool
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Transcript of Relief: A Modeling By Drawing Tool
Relief: A Modeling by Drawing Tool
David Bourguignon1 Raphaëlle Chaine2
Marie-Paule Cani3 George Drettakis4
1Princeton University / INRIA Rocquencourt 2LIRIS / CNRS / UCBL3GRAVIR / INP Grenoble 4REVES / INRIA Sophia-Antipolis
Outline
• Motivation• Previous Work• Tool Workflow• Reconstruction• Adaptive Sampling & Depth Inference• Tool Interface• Results
On Users
• Most people draw– Writing alternative
• Few people sculpt– Play-Doh days long gone– Materials difficult to handle
Goals
• Use 2D tools to perform 3D operations
Goals
• Use 2D tools to perform 3D operations• Model global and local surface
Goals
• Use 2D tools to perform 3D operations• Model global and local surface• Input: just plain strokes
Goals
• Use 2D tools to perform 3D operations• Model global and local surface• Input: just plain strokes• Output: triangle mesh
Outline
• Motivations• Previous Work• Tool Workflow• Reconstruction• Adaptive Sampling & Depth Inference• Tool Interface• Results
Previous Work
• Depth painting [Williams, 1990]
+
Previous Work
• Gradient editing [van Overveld, 1996]
Previous Work
• Maya 6.0 Artisan [Alias, 2004]
Outline
• Motivations• Previous Work• Tool Workflow• Reconstruction• Adaptive Sampling & Depth Inference• Tool Interface• Results
Tool Workflow
• First step: drawing input– Displacement map
• mid-grey = 0• white > 0• black < 0
Model of 3D sphere
Pencil
Brush
Tool Workflow
• First step: drawing– Displacement map– 2D shape boundary
(in green)• defines drawing mask
Tool Workflow
• First step: drawing– Displacement map– 2D shape boundary– Displacement regions (from 2 maps)
Tool Workflow
• Second step: modeling– Displace existing vertices
Tool Workflow
• Second step: modeling– Displace existing vertices– Create new surface patch
Tool Workflow
• Changing viewpoint
Modeling by drawing
Changing viewpoint
Reconstruction
• Based on evolving pseudo-manifold [Chaine, 2003]
Reconstruction
• Based on evolving pseudo-manifold [Chaine, 2003]
• Satisfy our requirements– Arbitrary number of connected components
Reconstruction
• Based on evolving pseudo-manifold [Chaine, 2003]
• Satisfy our requirements– Arbitrary number of connected components– Handle points off shape boundary
Reconstruction
• Based on evolving pseudo-manifold [Chaine, 2003]
• Satisfy our requirements– Arbitrary number of connected components– Handle points off shape boundary– Interactive (5k points per second)
2D reconstruction
• Start: pseudo-curve lies on oriented edges of Delaunay triangulation
2D reconstruction
• During: pseudo-curve evolves as long as oriented Gabriel criterion is not met
2D reconstruction
• Stop: topologically consistent set of oriented edges
Sampling and Depth
• Adaptive sampling– Displacement map
• Pencil and brush datain color buffer
Color buffer
Sampling and Depth
• Adaptive sampling– Displacement map– Approximate disp. map
sampled at existing vertices
Sampling and Depth
• Adaptive sampling– Displacement map (D)– Vertex-Sampled disp.
map (V)– Error map
E = 1 – ABS(D – V)– Arbitrary error value
Sampling and Depth
• Adaptive sampling– Displacement map– Approximate disp. map– Error map– Sampling [Alliez, 2002]
Sampling and Depth
• Adaptive sampling• Depth inference
– Identify surface vertices
Vertices ID buffer
Sampling and Depth
• Adaptive sampling• Depth inference
– Identify surface vertices– Assign depth values
Depth buffer
Sampling and Depth
• Adaptive sampling• Depth inference
– Identify surface vertices– Assign depth values– Infer depth values
• from existing surface• by depth propagation
Outline
• Motivations• Previous Work• Tool Workflow• Reconstruction• Adaptive Sampling & Depth Inference• Tool Interface• Results
Tool Interface
• Hole marks– Comic books production
Hole marks
Stone #3 (Avalon Studios)
Tool Interface
• Hole marks– Comic books production– Our system
Hole mark
Tool Interface
• Video: Basic interface
Tool Interface
• Blobbing
Drawing White shadingDistance field Height field Surface
Tool Interface
• Depth modes (chosen by menu)
Modeling “at depth”Depth inference Frisket mode
Video
• Modeling a tree
Paper sketch 3D model obtained with Relief
Outline
• Motivations• Previous Work• Tool Workflow• Reconstruction• Adaptive Sampling & Depth Inference• Tool Interface• Results
Results
• Models (1k to 4k points)
Discussion
• Intuitive shading convention
Discussion
• Intuitive shading convention• Problems with drawing metaphor
– No continuous visual feedback• Provide two modes
Discussion
• Intuitive shading convention• Problems with drawing metaphor
– No continuous visual feedback– Difficult to obtain continuous shading
• Provide higher-level drawing tools
Conclusion
• Modeling by drawing, but imprecise
Conclusion
• Modeling by drawing, but imprecise• Future work
– Speedup with local 3D reconstruction
Conclusion
• Modeling by drawing, but imprecise• Future work
– Speedup with local 3D reconstruction– Improve depth inference
Conclusion
• Modeling by drawing, but imprecise• Future work
– Speedup with local 3D reconstruction– Improve depth inference– Image-space and object-space sampling
Acknowledgements
This work has been performed while the first author was a visiting research fellow at Princeton University, supported by an INRIA post-doctoral fellowship.
Many people have indirectly contributed to it. We would like to thank: Adam Finkelstein, Szymon Rusinkiewicz, Jason Lawrence, Pierre Alliez, Mariette Yvinec, Laurence Boissieux, Laure Heïgéas, Laks Raghupathi, Olivier Cuisenaire, Bingfeng Zhou.