The Simulation of Paint Cracking and Peeling

Transcription

1 The Simulation of Paint Cracking and Peeling E. Paquette 1,2, P. Poulin 1, G. Drettakis 2 1 2

2 Realism Realistic / believable images e-commerce architecture Simulation (Physics, Mathematics) Precision (perception, measurement) Constraints (time, memory) Tradeoff (increased realism) effects

3 Aging Synthetic objects often look too perfect Deterioration environment everyday use Long term before after

4 Aging in Computer Graphics Important for realism film virtual reality video games design / prototyping Semi-automatic methods Control before after

5 Peeling Thin layer (paint) Cracks, peels photo photo

6 Outline Peeling Previous work Simulation Implementation Results Conclusion

7 Paint Properties Elasticity can be stretched Tensile stress force required to stretch Tensile strength force required to tear Adhesion strength force required to peel

8 Paint Properties Elasticity can be stretched Tensile stress force required to stretch Tensile strength force required to tear Adhesion strength force required to peel

9 Paint Properties Elasticity can be stretched Tensile stress force required to stretch Tensile strength force required to tear Adhesion strength force required to peel

10 Paint Properties Elasticity can be stretched Tensile stress force required to stretch Tensile strength force required to tear Adhesion strength force required to peel

11 Physical Phenomenon Paint dries, shrinks, tensile stress Deterioration moisture, uv, pollution elasticity, strength, adhesion Peeling cracks, loss of adhesion, peels

12 Method Simplified model easy control efficiency Surface properties Cracks formation and propagation Loss of adhesion Peeling synthetic

13 Outline Peeling Previous work Simulation Implementation Results Conclusion

14 Previous Work Fracture [Norton1991] [Hirota2001] [O'Brien1999] [Smith2000] Cracks [Hirota1999] [Gobron2001]

15 Previous Work Peeling [Wong1997] tendency (peeling sources, 3D noise) threshold (no simulation) [Gobron2001] cellular automata order in which parts detach

16 Previous Work Peeling [Wong1997] tendency (peeling sources, 3D noise) threshold (no simulation)

17 Previous Work Peeling [Gobron2001] cellular automata order in which parts detach 3 6

18 Outline Peeling Previous work Simulation Implementation Results Conclusion

19 Overview Top view: paint layer 1- stress crack movement decrease of (strain) lateral stress

20 Overview Side view: paint 5- peeling 2- movement (strain) 3- decrease of tensile stress 1- stress 3- increase of shearing stress base 4- loss of adhesion

21 Implementation Paint properties 2D grid directional Cracks sequence of linear segments independent of the grid

22 Cracks Control Texture tensile strength white = low

23 Creation Perpendicular to the maximum ratio Grid property: tensile stress tensile strength New crack

24 Propagation Perpendicular to the maximum ratio Grid property: tensile stress tensile strength

25 Relaxation Perpendicular to the crack Grid property displacement induced by the relaxation

26 Adhesion Loss with respect to ratio Grid property shearing stress adhesion strength Adhesion loss distance

27 Peeling Curls perpendicular to the crack Local geometry Control: mesh resolution 1φ 3φ 2φ θ cross section mesh rendered

28 Peeling Direction Crack path is "jaggy" Direction of peeling is more continuous photo

29 Peeling Direction Direction of peeling is even more continuous photo

30 Segment Fusion Level of detail Fusion metrics loss of adhesion length direction Detail information

31 Intersection Crack propagation crack IDs

32 Intersection Crack propagation

33 Intersection Crack propagation Detect with crack ID wrong ID

34 Intersection Crack propagation Detect with crack ID Join intersecting to intersected

35 Intersection Crack propagation Detect with crack ID Join intersecting to intersected Compute relaxation

36 Intersection Crack propagation Detect with crack ID Join intersecting to intersected Compute relaxation Split the intersected crack

37 Outline Peeling Previous work Simulation Implementation Results Conclusion

38 Simulation System Simulation system crack formation & propagation relaxation and adhesion Cracks information path, widths Rendering

39 Maya Plugins paint base color cracks geometry

40 Outline Peeling Previous work Simulation Implementation Results Conclusion

41 Results: Wall photo aged 2 nd view

42 Results: Shutters photo aged 2 nd view

43 Results: Garage Door photo 2 nd view aged

44 Results: Video Propagation wall text (GI 2002)

45 Results: Statistics wall shutters garage nb crack segments simulation 3 min 20 min 75 min (400 MHz) rendering 3 min 3 min 3 min (16 x 400 MHz)

46 Outline Peeling Previous work Simulation Implementation Results Conclusion

47 Conclusion Control through textures Cracks and loss of adhesion Peeling Local geometry Segment fusion

48 Extensions Multi-layer paint over primer over base surface Multi-processing one crack / processor Interaction with other effects example: rust

49 Questions? Thanks to Alias Wavefront NSERC, FCAR, MRI-MEQ, FES-UdeM, INRIA, UFJ M. Glisse, A. Reche, C. Puech