AR question -->phong, blinn, or oren nayar?

[georgedrakakis]

hmm, a little google research and a lot of interesting stuff like this:
http://www.the123d.com/tutorial/general4/reflections2-1.shtml

[Rich-Art]

Phong is more for plastic materials.
Blinn is more or less the same but this one has a much more accurate higlights and is a better choise for metals.
Oren-Nayar is more for rough surfaces, like sand, dirt, fabrics...
There is a list in the manual with "refractive index" for a lot of materials.

Peace,
Rich-Art. :thumbsup:

[georgedrakakis]

tnx Rich-Art,
i was just about reading the tut i posted earlier.
the index i am looking is exactly what you posted.
phong for plastics,
blinn for metals, etc.

i think there is a lot of try & error waitng for me while tweeking settings to found out how different settings react on objects.

[Martin Kay]

hey guys,
i think that setting up materials is as important as setting up lights.
in fact, you can't do the one without the other.
so, i've noticed these settings in illumination channel, and i wonder which is the best way to apply on a matte, shiny, plastic, fabric, or metal material.
are there any indexes (i.e refractive index) for materials according to their nature, surface and behavior to direct-indirect light?
or am i asking too much?
i think that reading the manual a long time ago wasn't helpfull (perhaps i wasn't ready to understand it)
tia,
george

The blinn illumination model gives nicer highlights- they stretch and elongate round curves more than the phong model. Try it! Oren Nayer is for very 'matt' objects.

Martin K

[LucentDreams]

phong is faster but less accurate, specifically in its highlight.

Blinn is marginally slower, especially with todays systems the difference is practically immeasurable really. Its very similar in its diffusion to phong but the highlight is more accurate both in initial faloff and shape around surfaces.

Oren nayer is slower than blinn, sometimes noticable, especially if you switch enough blinn shaded objects to oren nayer. oren nayer is however based on blinn, just with an additional roughness setting for the diffusion. This roughness setting when set to 0% will make it identical to blinn, but still has the render hit.

Now while I've discussed render speed decrease, I shoudl emphasize that really on todays systems this hit is soooo vastly insignificant really in terms fo rendertimes. These types of shading models can be handled by realtime gpu pixel shaders quite easily.

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