利用者:Guiseppe/Oren Nayar

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.

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."

And this is why you should use Oren-Nayar Shader.