"HenryW" <pov### [at] henrywagnerorg> wrote in message
news:web.3f43c86f4e495bb8aa8c3f990@news.povray.org...
>
> I've been working on a POV model of a football stadium:
>
> http://www.henrywagner.org/povray/images/POPMart2.htm
> http://www.henrywagner.org/povray/images/POPMart3.htm
>
> Currently the model is generated using the POV scripting syntax to
generate
> the stadium out of triangles in the shape of an ellipse. As I add more
> details, the number of triangles is getting out of control. Today it hit
> me, I could just define the points that make up the profile and "sweep"
the
> stadium out with lathe or sor, but I haven't been able to figure out how
to
> create the elliptical shape. One idea is to create a spherical stadium and
> use "scale" to stretch it along one axis, but I don't think that will look
> right. Is there away to sweep an object along an elliptical path? Any
other
> ideas of how to speed this up?

I passed this message up before thinking someone would give you some kind of
answer before now. I was thinking perhaps something Tor Olav Kristensen has
done in the past might help. Mainly because he's done some great things with
manipulating POV-Ray objects. Unfortunately I'm not finding the exact thing
to show you. Only this:

http://news.povray.org/povray.general/23254/

But there's also 'prism', which could be plotted out into a ellipse and be
made conical at the same time. Might take a little learning if you're
unfamiliar with it but that would be my best suggestion.

Well, maybe you can adjust this one:

// stadium
prism {
  conic_sweep
  cubic_spline
  0.5,         // height 1
   1,         // height 2
  22,           // number of points
/* now the uv vectors */
// inner
  < -0.5, -1.5>*0.9,
  < 0,  -2>*0.9,
  < 1, -1.5>*0.9,
  < 1.25,  0>*0.9,
  < 1,  1.5>*0.9,
  < 0,  2>*0.9,
  < -1,  1.5>*0.9,
  < -1.25, 0>*0.9,
  < -1,  -1.5>*0.9,
  < 0, -2>*0.9,
  < 0.5,-1.5>*0.9,
// outer
  < -0.5, -1.5>,
  < 0,  -2>,
  < 1, -1>,
  < 1.25,  0>,
  < 1,  1>,
  < 0,  2>,
  < -1,  1>,
  < -1.25, 0>,
  < -1,  -1>,
  < 0, -2>,
  < 0.5,-1.5>
     pigment {rgb 1}
scale <1,0.667,1>
}

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