"PM 2Ring" <nomail@nomail> wrote in message
news:web.42edf3bf208413009143b5c90@news.povray.org...
> The catenary is the curve formed by a homogeneous chain suspended between
> two points in a uniform gravity field. It looks like a parabola, but it's
> mathematically quite different. The equation of a parabola is just
>  y = a*x*x, a simple quadratic, whereas a catenary is
>  y = a*cosh(x/a), a transcendental equation.
>
> I had occasion to look at Chris Colefax's chain building code in
"Linc.inc",
> after referring a new user to it, and was dismayed to discover that Chris
> used quadratics to build his chains. :(
>
> The Chain() macro below constructs a true catenary. This is a preliminary
> draft, so there are no docs as yet, sorry. Read the comments for hints. :)
>
> Any questions and comments are most welcome. Have fun!

Cool cool. I think about this occasionally, probably everytime i see a
cosh()  for some reason. This is the same curve that would describe wires
between telephone poles, right?

anyway, neat work. i await the realistic glass render although the fake
glass looked pretty too :)

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