grace@iitmax.IIT.EDU (Thom Grace) (03/09/89)
In article <238@anselm.UUCP> pfarrell@anselm.UUCP (Gladiator) wrote
something like:
]Here is an interesting thought. If there were no shadows everything
]would look completely flat. Anybody agree or disagree with
]that statement?
Well, I seem to have accidentally blown away my original response, but
I read a "disagree" in the meantime. I agree with the "disagree". The
people who started shadow generation pretty much covered this question
some time ago (at least that's how I interpret their stuff).
The "flatness" of an individual object is not really a function of the
shadows it casts, nor of the shadows other objects cast upon it. Indeed
(following the other posting alluded to above), a sphere in otherwise empty
space certainly has no interaction with any shadows. Instead, the 3D
perception of an individual object is more a result of shading (like
Gouraud, Phong, Torrance-Sparrow, etc.).
This is not to say that shadows are unimportant: the relative position(s)
of (pairs of) individual objects are perceived by several visual cues, one
of which is shadowing. I'll close this rambling by citing an example
provided by Dr. F. Crow at a fairly remote SIGGRAPH: Suppose there's an
orange and a table ... we have trouble judging whether the orange is sitting
on the table or floating above the table if there are no shadows.
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Thom Grace | |
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