tada@athena.mit.edu (Michael Zehr) (02/29/88)
Thanks to all of you who sent replies to my question (what makes a good
silver, and what are good references for color models for ray-tracing).
Here is a summary of what people said:
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From: Tommie D. Daniel <cs3631be@hydra.unm.edu>
An Improved Illumination Model for Shaded Display
Turner Whitted
Communications of the ACM
June 1980 Vol. 23 Number 26
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From: Charlie Gibson <charlie@tis.llnl.gov>
Subject: Nice looking Silver....
I've never been able to get good looking silver until I started using
environmental reflection mapping. Silver looks "silver" not because of
it's "color", but because it takes on the colors of the surrounding
environment. Check out a magazine and look at hand-airbrushed chrome
logos. You'll typically see the "classic chrome" environment reflected
into the logo: Brown ground gradating up to a blue sky. Reflection
maps are a great cheat -- if your software can support them.
For a more proper solution, check out Rob Cook's SIGGRAPH '81 Paper on
simulation of metallic surfaces. It explains the limitations of Phong
shading when it comes to metal; and why you probably won't get good
looking silver using Phong's light model.
However, if you want a more specific description of how WE do silver,
(We assume RGB to be in the range 0..1)
Diffuse & Ambient are low (0.05 0.05 0.05) Specular is Mirror (1.0 1.0
1.0) Specular Exponent is the maximum allowed by your renderer (500 for
us) Reflection Map contribution Coefficient is mirror. (1.0 1.0 1.0)
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From: trainor@CS.UCLA.EDU (Vulture of Light)
[] Cook, R.L., Torrance, K., A Reflectance Model for Com-
puter Graphics, Computer Graphics, Vol. 15, No. 3,
August 1981.
[] Cook, R.L., A Reflection Model for Realistic Image Syn-
thesis, Masters Thesis, Cornell Univ., December 1981.
[] Cook, R.L., Shade Trees, Computer Graphics, Vol. 18,
No. 3, July 1984.
[] Kajiya, J.T., The Rendering Equation, Computer Graph-
ics, Vol. 20, No. 4, July 1986.
[] Whitted, T., An Improved Illumination Model for Shaded
Display, Communications of the ACM, Vol. 23, No. 6,
June 1980.
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From: oltz@tcgould.tn.cornell.edu (Michael Oltz)
For your question of a paper, a good place to start is 'A Reflectance
Model for Computer Graphics' in the proceedings of 1981 SIGGRAPH,
which proceedings were published as Vol 15 No 3 of 'Computer Graphics'.
The paper is by Robert L. Cook and Kenneth E. Torrance, and is on
p. 307-316 of the proceedings. Whenever I have a question about
some area of computer graphics, I would start with the two best-known
graphics texts, Foley and Van Dam's "Fundamentals of Interactive
Computer Graphics", and Newman and Sproull's "Principles of Interactive
Computer Graphics." Then I would look in SIGGRAPH proceedings from
most recent and going back.
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From: many others
[references to 1982 SIGGRAPH paper]
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Thanks again everyone.
My apologies if this is too long. I'm new at summarizing for the net.
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michael j zehr
"My opinions are my own ... as is my spelling."