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Interactive Design of Botanical Trees using Freehand Sketches and Example-based Editing

Interactive Design of Botanical Trees using Freehand Sketches and Example-based Editing. Makoto Okabe 1 , Shigeru Owada 1,2 , Takeo Igarashi 1,3 The University of Tokyo 1 , Sony CSL 2, JST PRESTO 3. Introduction Motivation Previous Work Our method User Interface Details Result

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Interactive Design of Botanical Trees using Freehand Sketches and Example-based Editing

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  1. Interactive Design of Botanical Trees using Freehand Sketches and Example-based Editing Makoto Okabe1, Shigeru Owada1,2 , Takeo Igarashi1,3 The University of Tokyo1, Sony CSL2, JST PRESTO3

  2. Introduction • Motivation • Previous Work • Our method • User Interface • Details • Result • Discussion

  3. Motivation • 3D trees are important in • Cityscape design • Virtual reality • Consumer games • 3D tree modeling is difficult • Enormous structural complexity

  4. Previous Work • Rule-based approaches • L-systems • Xfrog • SpeedTree Difficult for novices • 3D tree libraries • Maya - Paint Effects Difficult to design an arbitrary tree

  5. Our method • For quick and easy design of trees, we propose • Sketch-based modeling 2D sketch 3D model • Example-based modeling Sparse Dense

  6. Introduction • User Interface • Modeling Process • Demonstration • Details • Result • Discussion

  7. Modeling Process (b) 3D Construction (c) Multiplication (a) 2D Sketch (d) Leaf-arrangement (e) Propagation

  8. Demonstration

  9. Introduction • User Interface • Details • Creating a 3D Tree from a 2D Sketch • Extension of the Basic Algorithm • Creating a Branch with Spiral Structure • Example-based Leaf Arrangements • Result • Discussion

  10. Creating a 3D Tree from a 2D Sketch • Decide depths of branches • Keep the appearance from the view point • Resulting shape has infinite possibility

  11. Creating a 3D Tree from a 2D Sketch • Observation of natural trees • A natural tree spreads their branches to absorb sun light as efficiently as possible • The distances between a branch and other branches tend to be as large as possible

  12. Creating a 3D Tree from a 2D Sketch • Decide depths of branches one by one • Compute distances between branch shadows • Maximize distances among branches

  13. 2D Convex Hull 3D Hull Creating a 3D Tree from a 2D Sketch • Other constraints • A 3D hull obtained from the 2D convex hull • Keep the overall shape of a tree • Length of a branch • Angle between two branches

  14. Extension of the Basic Algorithm • Problem of the described algorithm • Front view is kept • Side view is strange People omit branches spreading backward or forward front view side view

  15. 90 degrees Extension of the Basic Algorithm • simple ad hoc trick basic algorithm merging rotated version(by 90 degrees)

  16. front view side view Extension of the Basic Algorithm • The resulting 3D tree • Front and side views look similar

  17. (a) (b) (c) Creating a Branch with Spiral Structure • Decide depth values so that the branch stroke has a constant 3D curvature • [Floral diagrams and inflorescences, Ijiri et al, SIGGRAPH 2005] Calculate yi so that

  18. Resulting 3D Trees • 2Dsketch  resulting 3Dtree models

  19. Example-based Leaf Arrangements • Three types of leaf arrangements Geminatus Alternating Whorled

  20. Example-based Leaf Arrangements Geminatus Whorled Alternating

  21. Introduction • User Interface • Details • Result • Designed by Experts • Designed by Test Users • Comparison to Other Systems • Discussion

  22. Designed by Experts (a) young tree (b) zelkova (c) maidenhair 7,900 nodes 30,000 nodes 4,300 nodes

  23. Designed by Test Users (a) 6 min (b) 8 min (c) 7 min (d) 9 min (e) 6 min (f) 6 min

  24. Comparison to Other Systems • L-system, Xfrog and our system • Recruited 3 novice users(A, B, C) • L-system (A and B together) • Xfrog (C) • Our system (A, B, C individually) • Photograph of a target tree

  25. Comparison to Other Systems Photograph L-system ( 60min ) XFrog ( 30 min )

  26. Comparison to Other Systems Photograph Our method (10min) Our method (10 min)

  27. Comparison to Other Systems • Our system • The major branching structures by sketching • The other systems • Detailed structures produced by rules

  28. Introduction • User Interface • Details • Result • Discussion • Summary • Limitations and Future Work

  29. Summary • We proposed a system for quick and easy design of 3D trees • Creating a 3D Tree from a 2D Sketch • Example-based modeling • The user can design a tree intuitively, especially major branching structures • User Tests • cf) Rule-based systems

  30. Limitations and Future Work • Incorporating more natural phenomena • e.g.) Tropisms from user-defined branches • Construction of forest • Editing operations • move, rotate, or bend

  31. Thanks • contact information • Makoto Okabe (makoto21@ui.is.s.u-tokyo.ac.jp) • www for this project • http://www-ui.is.s.u-tokyo.ac.jp/~makoto21 • Thanks very much • This work was funded in part by the Japanese Information-Technology Promotion Agency (IPA) • Eurographics reviewers

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