1. Mesh Modelling With Curve Analogies
Steve Zelinka Michael Garland
University of Illinois at Urbana-Champaign

2. In a Nutshell

3. Overview Motivation Related Work Details of our Approach Results
Curve Selection
Surface Transformation
Results
Future Work

4. Motivation Reduce artistic skill required for modelling
Solution: Modelling by Analogy A : A’ :: B : ?
Images [Hertzmann et al 2001]
Curves [Hertzmann et al 2002]

5. Mesh Analogies?
User burden
Unsolved technical issues
: :: : ?

6. Related Work
Geometric texture synthesis [Bhat et al 2004] [Lagae et al 2004]

7. Related Work
Common parameterizations [Kraevoy and Sheffer 2004] [Schreiner et al 2004] [Allen et al 2003]
Deformation transfer [Sumner and Popovic 2004]

8. Related Work Generative modelling [Snyder 1992]
Wires [Singh and Fiume 1998]
Poisson-based editing [Yu et al 2004]

9. Related Work
Teddy [Igarashi et al 1999, 2001]

10. Approach Overview Select surface curves
Transform surface curves with Curve Analogies
Transform the surface
2D sketch-based manipulation
Simple implementation

11. Curve Selection
Planar intersection curves
Parallel or rotating slices

12. Curve Selection Planar intersection curves Silhouette curves
Parallel or rotating slices
Silhouette curves

13. Generality Issues Features controlled only on and along curves
Use orthogonal, intersecting sets of curves
Multiple passes

14. Curve Analogies User sketches unfiltered, filtered curves
Identical parameterizations required
System iteratively copies offsets to target

15. Curve Analogies Joint neighbourhood matching
Find best t with A(t) ~ B(tcurr), A’(t) ~ B’(tcurr)
Neighbourhoods must be aligned before comparison

16. Surface Transformation
Similar to Wires
Vertices near a curve track movement of their closest points on the curve

17. Surface Transformation
Similar to Wires
Vertices near a curve track movement of their closest points on the curve
Vertex movement inversely proportional to distance to curve

18. Surface Transformation
Similar to Wires
Vertices near a curve track movement of their closest points on the curve
Vertex movement inversely proportional to distance to curve
Parallel local frames

19. Influence Radius Radius of influence of each curve can be varied
Can also vary fall-off function

20. Influence Radius Radius of influence of each curve can be varied
Can also vary fall-off function

21. Influence Radius Radius of influence of each curve can be varied
Can also vary fall-off function

22. Multiple Curves Vertices can be influenced by multiple curves
Candidate position from each influencing curve
Final position weighted average of candidates

23. Results Curve Analogies Dominate compute time
Can be difficult to control

24. Results

25. Results

26. Results
Harmonic fields [Ni et al 2004]

27. Future Directions Better Curve Analogies
Avoid orientation flipping using surface information
Use intrinsic curve parameterization to accelerate
Spatial influences near intersections

28. Future Directions More curve families Iso-parameter curves
Signal-specific curves
Suggestive contours [DeCarlo et al 2003]

29. Future Directions Poisson-based surface transformation
Can we use Image Analogies similarly?

30. Thanks Funded in part by a grant from the NSF (CCR-0086084)
Software/source code at: