Mesh Modelling With Curve Analogies

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Mesh Modelling With Curve Analogies

• Steve ZelinkaMichael Garland
• University of Illinois at Urbana-Champaign

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In a Nutshell
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Overview

• Motivation
• Related Work
• Details of our Approach
• Curve Selection
• Surface Transformation
• Results
• Future Work

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Motivation

• Reduce artistic skill required for modelling
• Solution Modelling by Analogy A
  A B ?
• Images Hertzmann et al 2001
• Curves Hertzmann et al 2002

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Mesh Analogies?

• User burden
• Unsolved technical issues
• 
  ?

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Related Work

• Wires Singh and Fiume 1998
• Excellent control over editing
• Highly skilled artist required

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Related Work

• Teddy Igarashi et al 1999
• Intuitive sketch-based interface
• Limited class of models

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Approach Overview

• Select surface curves
• Transform surface curves with Curve Analogies
• Transform the surface
• 2D sketch-based manipulation
• Simple implementation

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Curve Selection

• Planar intersection curves
• Parallel or rotating slices
• Orthogonal to skeleton

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Curve Selection

• Planar intersection curves
• Parallel or rotating slices
• Orthogonal to skeleton
• Silhouette curves

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Generality Issues

• Features controlled only on and along curves
• Use orthogonal, intersecting sets of curves
• Multiple passes

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Curve Analogies

• User sketches unfiltered, filtered curves
• Identical parameterizations required
• Based on joint neighbourhood matching
• Neighbourhoods must be aligned before comparison

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Surface Transformation

• Similar to Wires
• Vertices near a curvetrack movement oftheir
  closest points onthe curve

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Surface Transformation

• Similar to Wires
• Vertices near a curvetrack movement oftheir
  closest points onthe curve
• Vertex movementinversely proportional to
  distance to curve

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Influence Radius

• Radius of influence of each curve can be varied

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Influence Radius

• Radius of influence of each curve can be varied

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Influence Radius

• Radius of influence of each curve can be varied

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Multiple Curves

• Vertices can be influencedby multiple curves
• Candidate position from each influencing curve
• Final position weighted average of candidates

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Results

• Curve Analogies
• Dominate compute time
• Can be difficult to control

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Future Directions

• Better Curve Analogies
• Avoid orientation flipping usingsurface
  information
• Use intrinsic curveparameterization toaccelerate

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Future Directions
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Future Directions

• Influence radius
• Use spatially-based multi-analogies
• Adaptive setting
• Dynamics-based Surface Transformation
• Prevent self-intersections
• Allow topology changes

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Thanks

• Funded in part by a grant from the NSF
  (CCR-0086084)
• Contact Steve Zelinka
• zelinka_at_uiuc.edu
• Michael Garland
• garland_at_uiuc.edu