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space and photo sensitive l systems andrew leeuwenberg n.
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Space and Photo sensitive L-Systems Andrew Leeuwenberg

Space and Photo sensitive L-Systems Andrew Leeuwenberg

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Space and Photo sensitive L-Systems Andrew Leeuwenberg

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  1. Space and Photo sensitive L-Systems Andrew Leeuwenberg

  2. Content • Rational • Project overview • Proposed method • Tree generation • Environmental impact • Coding • Current stage • Next stage

  3. Rationale • CGI environments King Kong (2005) Avatar (2009) Brave (2012)

  4. The Project

  5. Project Statement “To procedurally generate trees whose growth is affected by light and space availability”

  6. Plug-in goals

  7. Plug-in goals

  8. Plug-in goals

  9. Approach

  10. Procedural Plants • Fractal concept • Self similarity • Not true fractals • Finite Oppenheimer, P. E. (1986).

  11. Self similarity

  12. Plant Fractals • Good for: http://trutextures.blogspot.co.uk/2012_03_01_archive.html

  13. Plant Fractals while (branches) { if (branchWidth < var) { draw leaf } else { } } Variables: Stem width Stem length Branch angle Divide number Twist angle 0.2 1.0 45° 2 30° grow / divide / twist

  14. Statistically similar

  15. Plant Fractals • Stochastic variance while (branches) { if (branchWidth < var) { draw leaf } else { grow / divide / twist ... etc } } Variables: Stem width Stem length Branch angle Divide number Twist number 0.2 1.0 45° 2 30° ± 0.05 ± 0.2 ± 15 ± 1 ± 10

  16. Plant Fractals • Stochastic variance Oppenheimer (1986)

  17. L-Systems • String rewriting • Axiom (ω) • Generations • Processors • Predecessor →Successor • Final string • Alphabet • F • 2 • F → F-F • F-FF-F • F+-&\/{}[] Prusinkiewicz & Lindenmayer (1990)

  18. L-Systems • Create fractal approximations

  19. L-Systems • Context-sensitive b < a → b a → a b → a ω = baa p1 = aba p2 = aab

  20. L-Systems • Context-sensitive • Stochastic F → F + [-F] F → FF - FF F → F + [-F] 0.4 0.4 0.2

  21. Environment

  22. Voxel space Greene (1989)

  23. Voxel space

  24. Growth avoidance

  25. Growth avoidance

  26. Growth avoidance

  27. Growth avoidance

  28. Growth avoidance

  29. Growth avoidance

  30. Growth avoidance

  31. Light availability

  32. Light availability

  33. Light availability

  34. Light availability

  35. Light availability

  36. Light availability  

  37. Light availability   

  38. Light availability    

  39. Light availability     0.5

  40. Integrating with L-System

  41. Modifying L-System • Light availability • Length • Override L-System • Don’t grow leaves < threshold • Stochastic weighting • Heliotropism • Direction of growth

  42. Light availability • Rewrite while drawing • Stochastic L-System • Weighted probabilities • Voxel luminosity (Ls) F → F + [-F ] F → F - FF F → F + [-F] L L L 0.33 Ls LS = 0.5 0.33 0.34

  43. Light availability • Rewrite while drawing • Stochastic L-System • Weighted probabilities • Voxel luminosity (Ls) F → F + [-F ] F → F - FF F → F + [-F] L L L 0.33 Ls LS = 0.8 0.33 0.34

  44. Light availability • Rewrite while drawing • Stochastic L-System • Weighted probabilities • Voxel luminosity (Ls) F → F + [-F ] F → F - FF F → F + [-F] L L L 0.7 Ls LS = 0.8 0.2 0.1

  45. Leaf problem p1

  46. Leaf problem p2

  47. Leaf problem p3

  48. Leaf problem p3

  49. Light availability F → F + [-F ] F → F - FF F → F + [-F] L L L 0.7 Ls LS = 0.8 0.2 0.1

  50. Light availability F → F + [-F ] F → F - FF F → F + [-F] L L L 0.7 Ls p3 0.2 0.1