The normal is an imaginary vector at each vertices of the triangle that
declares which way is "up" to that point. By adjusting the "up" vectors at
each point in a mesh of smooth triangles you can create the illusion that the
bump surface of the triangles are joined into one smooth surface, you don't
actually change the surface of the triangle, just it's appearance.
This is similar to a normal statement in a regular POV-Ray texture. It adjusts
the way light interacts with the surface by faking the smoothness of the
circle.
There is a good explanation of it in the ANSI C source code at
http://www.students.tut.fi/~warp/PovUtils/smooth.html
on Warps page. It is very well done and I used this method in my bezier.inc
file.


Mike Weber wrote:

> I was just reading about the smooth triangle vs. traingle in the POV docs.
> I fully understand the triangle object - but the smooth triangle I don't
> because of the normals.  What are normals? How are they used?  I've seen
> them used in OpenGL code and don't understand them there either.
>
> mike
> www.geocities.com/mikepweber

--
Josh English
eng### [at] spiritonecom
"May your hopes, dreams, and plans not be destroyed by a few zeros."

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