The document discusses computer-assisted stylized shading techniques for conveying lighting, material, and shape using both 2D and 3D drawing tools. It highlights various research challenges, applications, and tools available for artists and programmers, as well as future directions for 2D and 3D technologies. Additionally, it provides contact information and links to resources for further exploration of the subject.

1. Stylized shading

2. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…

3. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 2D drawing tools:
 Accurate control over stylized appearance
Χ Skill-demanding and time-consuming

4. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 2D drawing tools:
 Accurate control over stylized appearance
Χ Skill-demanding and time-consuming
Jelly Sunday (2009)

5. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 2D drawing tools:
 Accurate control over stylized appearance
Χ Skill-demanding and time-consuming
Jelly Sunday (2009)

6. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 2D drawing tools:
 Accurate control over stylized appearance
Χ Skill-demanding and time-consuming
Jelly Sunday (2009)

7. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 2D drawing tools:
 Accurate control over stylized appearance
Χ Skill-demanding and time-consuming
Jelly Sunday (2009)

8. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 2D drawing tools:
 Accurate control over stylized appearance
Χ Skill-demanding and time-consuming

9. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 3D graphics tools:
 Setup lighting and reuse through whole sequence
Χ Existing styles are limited & difficult to control

10. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 3D graphics tools:
 Setup lighting and reuse through whole sequence
Χ Existing styles are limited & difficult to control
« Meet Buck » rendering process

11. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 3D graphics tools:
 Setup lighting and reuse through whole sequence
Χ Existing styles are limited & difficult to control
« Meet Buck » rendering process

12. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 3D graphics tools:
 Setup lighting and reuse through whole sequence
Χ Existing styles are limited & difficult to control
« Meet Buck » rendering process

13. Motivation
 Computer-assisted stylized shading
 Convey lighting, material and shape at once!
 More legible, more iconic, more personal…
 Using 3D graphics tools:
 Setup lighting and reuse through whole sequence
Χ Existing styles are limited & difficult to control
« Meet Buck » rendering process

14. Research challenges
 Quite diverse goals:
 Assist in the drawing of smooth-shaded images
 Provide control over 3D stylized shading

15. Research challenges
 Quite diverse goals:
 Assist in the drawing of smooth-shaded images
 Provide control over 3D stylized shading
 Family of solutions:
 Start from scratch: pure 2D drawing
 Get depth/normal images: deformations
 Rely on 3D light sources: simple shading
 Use a full 3D scene: global illumination

16. Research challenges
 Quite diverse goals:
 Assist in the drawing of smooth-shaded images
 Provide control over 3D stylized shading
 Family of solutions:
 Start from scratch: pure 2D drawing
 Get depth/normal images: deformations Shaders,
Applications
 Rely on 3D light sources: simple shading & plugins
 Use a full 3D scene: global illumination

17. Starting from scratch: 2D drawing

18. Starting from scratch: 2D drawing
 Simple color gradients
 Linear & radial

19. Starting from scratch: 2D drawing
 Simple color gradients
 Linear & radial
 Composition is difficult
 Shading style is limited

20. Starting from scratch: 2D drawing
 Gradient Meshes
 Patches w/ color ctrl pts

21. Starting from scratch: 2D drawing
 Gradient Meshes
 Patches w/ color ctrl pts
 Capture colors & shading

22. Starting from scratch: 2D drawing
 Gradient Meshes
 Patches w/ color ctrl pts
 Capture colors & shading
 Constrained by structure

23. Starting from scratch: 2D drawing
 Diffusion curves
 Bezier curves, color/blur ctrl pts
 Colors are diffused, then blurred

24. Starting from scratch: 2D drawing
 Diffusion curves
 Bezier curves, color/blur ctrl pts
 Colors are diffused, then blurred
 Structure more easily edited

25. Starting from scratch: 2D drawing
Videos are available on my website

26. Starting from scratch: 2D drawing
Videos are available on my website

27. Starting from scratch: 2D drawing
Videos are available on my website

28. Starting from scratch: 2D drawing
 Diffusion Curves using TPS
 Smoother diffusion
Using Heat eq. Using TPS eq.

29. Starting from scratch: 2D drawing
 Diffusion Curves using TPS
 Smoother diffusion
 More intuitive user interaction
 Still require dedicated solver Using Heat eq. Using TPS eq.

30. Using 2.5D images: image deformations

31. Using 2.5D images: image deformations
 2.5D image creation
 Simple drawing (ex: nDo2)

32. Using 2.5D images: image deformations
 2.5D image creation
 Simple drawing (ex: nDo2)
 Diffusion Curves extension
UV map
Normal map

33. Using 2.5D images: image deformations
 Texture draping
 Use UVs to deform texture
 Use normals for simple shading

34. Using 2.5D images: image deformations
 Texture draping
 Use UVs to deform texture
 Use normals for simple shading
 Limited texture & shading effects

35. Using 2.5D images: image deformations
 Surface flows
 Two deformation fields

36. Using 2.5D images: image deformations
 Surface flows
 Two deformation fields
 Deform gradients & images

37. Using 2.5D images: image deformations
 Surface flows
 Two deformation fields
 Deform gradients & images

38. Using 2.5D images: image deformations
 Surface flows
 Two deformation fields
 Deform gradients & images
 Deform brush footprints

39. Using 2.5D images: image deformations
 Surface flows
 Two deformation fields
 Deform gradients & images
 Deform brush footprints

40. Using 2.5D images: image deformations
 Surface flows: deformation operators
Videos are available on my website

41. Using 2.5D images: image deformations
 Surface flows: image tools
Videos are available on my website

42. Using 2.5D images: image deformations
 Surface flows: brush tools
Videos are available on my website

43. Using 2.5D images: image deformations
Videos are available on my website

44. Using 2.5D images: image deformations
 Cross-shade (for 2.5D normals)
 Draw construction curves

45. Using 2.5D images: image deformations
 Cross-shade (for 2.5D normals)
 Draw construction curves
 Infer normals all over interior

46. Using 2.5D images: image deformations
 Cross-shade (for 2.5D normals)
 Draw construction curves
 Infer normals all over interior
 Use for deformation or simple shading

47. Using 3D lights: simple shading

48. Using 3D lights: simple shading
 Use texture lookups
 Toon shading (ex: TeamFortress), Lit Spheres (ex: Z-Brush)

49. Using 3D lights: simple shading
 Use texture lookups
 Toon shading (ex: TeamFortress), Lit Spheres (ex: Z-Brush)
 Simple lighting, basic materials, no shape enhancement

50. Using 3D lights: simple shading
 Apparent Relief
 Compute curvature per pixel

51. Using 3D lights: simple shading
 Apparent Relief
 Compute curvature per pixel
 Map to 2D toon textures
 Only simple shading & materials

52. Using 3D lights: simple shading
 Dynamic Stylized Shading
 Primitive = param. + profile

53. Using 3D lights: simple shading
 Dynamic Stylized Shading
 Primitive = param. + profile
 Curvature-based deformation

54. Using 3D lights: simple shading
 Dynamic Stylized Shading
 Primitive = param. + profile
 Curvature-based deformation
 Blend multiple primitives

55. Using 3D lights: simple shading
Videos are available on my website

56. Using 3D lights: simple shading
Videos are available on my website

57. Going full 3D: global illumination

58. Going full 3D: global illumination
 3D unsharp masking
 Blur radiance signal & compute diff.
 Boost difference & add to original

59. Going full 3D: global illumination
 3D unsharp masking
 Blur radiance signal & compute diff.
 Boost difference & add to original
 Applied to arbitrary complex scenes

60. Going full 3D: global illumination
 3D unsharp masking
 Blur radiance signal & compute diff.
 Boost difference & add to original
 Applied to arbitrary complex scenes
 Lacks control over shape & materials

61. Going full 3D: global illumination
 Light Warping
 Shape conveyed by distortions

62. Going full 3D: global illumination
 Light Warping
 Shape conveyed by distortions
 Warp lights to enhance curvature
 Requires a natural lighting env.

63. Going full 3D: global illumination
 Light Warping
 Shape conveyed by distortions
 Warp lights to enhance curvature
 Requires a natural lighting env.

64. Going full 3D: global illumination
 Radiance Scaling
 Modify light intensities instead of directions
 Works with arbitrary lighting env. & material

65. Going full 3D: global illumination
Videos are available on my website

66. Going full 3D: global illumination
Videos are available on my website

67. Where to find these tools?

68. Where to find these tools?
 If you are a programmer: papers & shaders
Siggraph Siggraph Asia EGSR
3D Unsharp Masking (2008)
Diffusion Curves (2008) Texture Draping (2009)
Freeform Vect. Graph. (2011)
i3D NPAR
Cross Shade (2012)
Light Warping (2009)
Rad. Scaling (2010) App. Relief (2008) DSSP (2008)
Surface Flows (2012)

69. Where to find these tools?
 If you just want to try 2D drawing applications
 Diffusion Curves & extensions
 Cross Shade available soon…
Diffusion Curves Freeform Vector Graphics

70. Where to find these tools?
 If you just want to try 3D rendering applications
 Light Warping & Radiance Scaling
 Dynamic Stylized Shading available soon…
Light Warping inside Frapper (Filmakademie)
Radiance Scaling inside Meshlab

71. Where to find these tools?
 If you plan to use them in your projects
 Photoshop (Adobe): Surface Flows
 Nuke (The Foundry): Radiance Scaling
 MudBox (Autodesk): Dynamic Stylized Shading
 Modo (Luxology): Light Warping & Radiance Scaling
Surface Flows for Photoshop Radiance scaling for Nuke DSSP for Mudbox Light Warping &
(Pixel Bender - WiP) (Web Tutorial) (Viewport filter - prototype) Radiance Scaling for Modo
(Shader plugin - WiP)

72. What’s next… in 2D?

73. What’s next… in 2D?
 Vector drawing
 Plausible shading gradients
 Efficient rasterization algorithms
 2.5D deformations
 Create more complex materials
 Provide tools for animation
« Musician»
Tamara de Lempicka

74. What’s next… in 3D?
 Simple shading:
 Place highlights more accurately
 Capture shading from images
 Global Illumination:
 Direct control in image space
 Convey stylized materials
Textural light example
Burne Hogarth

75. Thanks
Research
Pierre Bénard, Hedlena Bezerra, Adrien Bousseau, Roland Fleming, Xavier Granier, Alexandrina Orzan,
Romain Pacanowski, Christophe Schlick, Joelle Thollot, David Vanderhaeghe, Romain Vergne
Animation
Denis Bouyer, Yann De Preval, Vincent E Sousa, Laurent Monneron, Ugo Bienvenu,
Julien Daubas, Clément Desnos, Florian Parrot, Arthur Peltzer
Contacts
Email: pascal.barla@inria.fr
(for questions, suggestions, collaborations)
Webpage: www.labri.fr/perso/barla
(go to ‘software’ page for code and applications)
CrossShade: www.crossshade.com
(Under construction)