From BlenderWiki
Oren-Nayar BSDF
Note
This table and all the original research and data, originates from the Columbia University. I am merely conveying this important information, to the Blender community.
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To my knowledge this is the first time this full list reach the public; in a user-readable format.
Sigma Table
http://www.cs.columbia.edu/CAVE/software/curet/html/sample.html (Pictures of the 61 samples)
| 1. Felt 0.414686 | 2. Polyester 0.576862 | 3. Terrycloth 0.458514 |
| 4. Rough Plastic 0.278057 | 5. Leather 0.179776 | 6. Sandpaper 0.513084 |
| 7. Velvet 0.751002 | 8. Pebbles 0.443289 | 9. Frosted Glass 0.416384 |
| 10. Plaster_a 0.362825 | 11. Plastic_b 0.543788 | 12. Rough Paper 0.311376 |
| 13. Artificial Grass 1.378872 (Red. More than 1?) | 14. Roof Shingle 0.819147 | 15. Aluminum Foil 0.252702 |
| 16. Cork 0.659956 | 17. Rough Tile 0.204088 | 18. Rug_a 0.566478 |
| 19. Rug_b 0.613889 | 20. Styrofoam 0.509725 | 21. Sponge 0.872413 |
| 22. Lambswool 0.978133 | 23. Lettuce Leaf 0.241785 | 24. Rabbit Fur 0.933632 |
| 25. Quarry Tile 0.360574 | 26. Loofa 0.300436 | 27. Insulation 0.136013 |
| 28. Crumpled Paper 0.274957 | 29. Polyester (Zoomed) 0.522950 | 30. Plaster_b (Zoomed) 0.520868 |
| 31. Rough Paper (Zoomed) 0.318498 | 32. Roof Shingle (Zoomed) 0.950521 | 33. Slate_a 0.356822 |
| 34. Slate_b 0.309590 | 35. Painted Spheres 1.211948 | 36. Limestone 0.413544 |
| 37. Brick_a 0.893379 | 38. Ribbed Paper 0.215297 | 39. Human Skin 0.579386 |
| 40. Straw 0.717587 | 41. Brick_b 0.275990 | 42. Corduroy 0.699112 |
| 43. Salt Crystals 0.481594 | 44. Linen 0.514593 | 45. Concrete_a 0.600672 |
| 46. Cotton 0.482679 | 47. Stones 1.107168 (Red. More than 1?) | 48. Brown Bread 0.784827 |
| 49. Concrete_b 0.308956 | 50. Concrete_c 0.461930 | 51. Corn Husk 0.387725 |
| 52. White Bread 0.507820 | 53. Soleirolia Plant 0.758465 | 54. Wood_a 0.598438 |
| 55. Orangle Peel 0.235808 | 56. Wood_b 0.351271 | 57. Peacock Feather 0.308792 |
| 58. Tree Bark 0.293226 | 59. Cracker_a 0.505978 | 60. Cracker_b 0.722678 |
| 61. Moss 0.542447 |
Sources
http://www.cs.columbia.edu/CAVE//projects/oren/ (The official website of CAVE Laboratory, Columbia Univertsity)
Quote:
"Most reflectance mechanisms can be broadly classified into two categories: diffuse and specular. In computer vision and computer graphics, the diffuse component is often assumed to be Lambertian; a surface that obeys Lambert's Law appears equally bright from all viewing directions. This model for diffuse reflection was proposed by Lambert over 200 years ago and has been perhaps the most widely used reflectance model in vision and graphics.
For several real-world surfaces, however, the Lambertian model can prove to be a poor and inadequate approximation of the diffuse component. The deviation from Lambertian behavior can be significant for a variety of real materials such as concrete, plaster, sand, etc. The primary reason for this deviation is the roughness of the surface.
[...] Extensive experiments have been conducted by the CAVE laboratory as well as other research groups to verify the accuracy of the model. Today, the Oren-Nayar model is frequently used in the creation of animations and special effects in movies. The model is available in most commercial rendering software such 3ds Max from Autodesk (formerly Discreet), Maya from Alias and Renderman from Pixar."
