1. Procedural and interactive icicle modeling Jonathan Gagnon Eric Paquette

2. Icy challenges Goal – Control – Fast computation 2 J. Gagnon & E. Paquette photograph

3. Overview 1.Previous work 2.Proposed approach 3.Results 4.Limitations & Conclusion 3 J. Gagnon & E. Paquette

4. Overview 1.Previous work 2.Proposed approach 3.Results 4.Limitations & Conclusion 4 J. Gagnon & E. Paquette

5. Previous work: Frost Microdroplets Kim et al. 2003 – Phase field Kim et al. 2004a – Phase field, DLA, fluid simulation – Realistic – No volume 5 J. Gagnon & E. Paquette

6. Previous work: Glaciology Makkonen 1988 – Growth vectors – Convection and conduction Maneo et al. 1994 – Dentritic growth Szilder et Lozowski 1994 – Predict the form 6 J. Gagnon & E. Paquette

7. Previous work: Computer Graphics Kharitonsky et Gonczarowski 1993 – Surface tension, tendency of water drop to follow a wet path. Kim et al. 2006 – Stephan problem Problems – Control – Computation time 7 J. Gagnon & E. Paquette

8. Overview 1.Previous work 2.Proposed approach 3.Results 4.Limitations & Conclusion 8 J. Gagnon & E. Paquette

9. Procedural icicle modeling 9 J. Gagnon & E. Paquette

10. Procedural icicle modeling 10 J. Gagnon & E. Paquette

11. Water Coefficients Goal – Compute the water flow Steps – Compute the water supply – Compute the water coefficient J. Gagnon & E. Paquette 11

12. Water Supply Source surface J. Gagnon & E. Paquette 12 Scatter & Ray-trace

13. Water Supply J. Gagnon & E. Paquette 13

14. Water Flow J. Gagnon & E. Paquette 14 Compute the water coefficient

15. Water Flow J. Gagnon & E. Paquette 15 Compute the water coefficient

16. Water Flow J. Gagnon & E. Paquette 16 Compute the water coefficient

17. Water Flow J. Gagnon & E. Paquette 17 Compute the water coefficient

18. Water Flow J. Gagnon & E. Paquette 18 Compute the water coefficient

19. Water Flow J. Gagnon & E. Paquette 19 Compute the water coefficient

20. Water Flow J. Gagnon & E. Paquette 20 Compute the water coefficient

21. Water Flow J. Gagnon & E. Paquette 21 Compute the water coefficient

22. Water Flow J. Gagnon & E. Paquette 22 Compute the water coefficient

23. Water Flow J. Gagnon & E. Paquette 23 Compute the water coefficient

24. Water Flow Compute the water coefficient J. Gagnon & E. Paquette 24

25. J. Gagnon & E. Paquette 25

26. Water Coefficients J. Gagnon & E. Paquette 26

27. Water Coefficients Works well with several surfaces J. Gagnon & E. Paquette 27

28. Procedural icicle modeling 28 J. Gagnon & E. Paquette

29. Drip points identification Goal – Find were the water drips Steps – Find drip region – Place drip points J. Gagnon & E. Paquette 29

30. Drip Criterion J. Gagnon & E. Paquette 30

31. Drip region J. Gagnon & E. Paquette 31

32. Drip points J. Gagnon & E. Paquette 32 Randomly distributed on the drip region

33. Procedural icicle modeling 33 J. Gagnon & E. Paquette

34. Icicles’ trajectories Goal – Create a guide for each icicle Previzualisation Interactive modification – Simulate different icicle types Straight Curved Divided J. Gagnon & E. Paquette 34

35. Icicles’ trajectories L-System J. Gagnon & E. Paquette 35

36. L-System J. Gagnon & E. Paquette 36

37. Broad range of results J. Gagnon & E. Paquette 37

38. Collision handling J. Gagnon & E. Paquette 38

39. Procedural icicle modeling 39 J. Gagnon & E. Paquette

40. Surface creation Goal – Create a photorealistic icicle mesh – Provide configurable surface – Manage fusion between icicles – Attach the icicle to the surface J. Gagnon & E. Paquette 40

41. Surface creation Methodology – Profile function – Icicle’s base function – Glaze ice function J. Gagnon & E. Paquette 41

42. Surface creation Methodology – Profile function – Icicle’s base function – Glaze ice function J. Gagnon & E. Paquette 42

43. Profile function J. Gagnon & E. Paquette 43

44. Profile function J. Gagnon & E. Paquette 44

45. Profile function { J. Gagnon & E. Paquette 45 {

46. Profile function J. Gagnon & E. Paquette 46

47. Implicit surface modeling Using metaballs Radius is defined by the profile function Positionned along the trajectory J. Gagnon & E. Paquette 47

48. Surface creation: results J. Gagnon & E. Paquette 48

49. Real vs generated J. Gagnon & E. Paquette 49

50. Surface creation Methodology – Profile function – Icicle’s base function – Glaze ice function J. Gagnon & E. Paquette 50

51. Icicle’s base J. Gagnon & E. Paquette 51

52. Icicle’s base J. Gagnon & E. Paquette 52

53. Icicle’s base Modeled with metaballs Radius function J. Gagnon & E. Paquette 53

54. Icicle’s base: Results J. Gagnon & E. Paquette 54

55. Surface creation Methodology – Profile function – Icicle’s base function – Glaze ice function J. Gagnon & E. Paquette 55

56. Three type of solidification J. Gagnon & E. Paquette 56 Glaze ice

57. J. Gagnon & E. Paquette 57

58. Glaze ice: Results J. Gagnon & E. Paquette 58

59. Overview 1.Previous work 2.Proposed approach 3.Results 4.Limitations & Conclusion 59 J. Gagnon & E. Paquette

60. Results J. Gagnon & E. Paquette 60 Video

61. L. Leblanc, J. Houle and P. Poulin Modeling with Blocks, CGI 2011. J. Gagnon & E. Paquette 61

62. Results statistics J. Gagnon & E. Paquette 62 FiguresTeapotFountainBuddhaBunnyArmadilloDragonTree Number of icicles123001020200 400 Computation times (seconds) Water coefficients0.1 0.50.350.40.3 Drip points0.10.50.20.10.5 Trajectories0.10.20.10.20.5 1 Surface modeling1155602011619.536 Total time11.355.860.820.612220.937.8

63. Overview 1.Previous work 2.Proposed approach 3.Results 4.Limitations & Conclusion 63 J. Gagnon & E. Paquette

64. Limitations Not physically accurate Implicit surface modeling is slow Rendering is slow J. Gagnon & E. Paquette 64

65. Conclusion J. Gagnon & E. Paquette 65 Control L-System to generate several icicle types Functions for ice thickness Interactivity Computation rearranged in four phases Fast computation of flow and trajectories

66. Questions J. Gagnon & E. Paquette 66

67. Curvature angle c J. Gagnon & E. Paquette 67

68. Dispersion angle au J. Gagnon & E. Paquette 68 a = au x 137.5˚/360 ˚