Wasn't it David Cameron who wrote:
>
>"David Cameron" <nom### [at] tome> wrote in message
>news:420d31cd@news.povray.org...
>>
>> "Alf Peake" <alf### [at] peake42freeservecouk> wrote in message
>> news:420d2321@news.povray.org...
>> > "David Cameron" wrote:
>> > > Hi All,
>> > > Do any of you know how to produce an elliptical torus?
>> > >
>> >
>> > This any use?
>> > http://mathworld.wolfram.com/EllipticTorus.html
>> >
>> > Alf
>> >
>> >
>>
>> Thanks for that Alf,
>> At first glance glance the diagram seems to suggest the ellipse is in the
>> y-z plane instead of the x-z plane (pov coordinate system), which I am
>sure
>> I could find a use for.
>> If I can figure out how to convert those equations to plug in to a
>> Parametric (preferably using param.inc), I will play around with it.
>
>Sorry, that was probably unclear Alf,
>I should have stated that object (at first glance appears to me) is
>eliptical around the minor radii and not the major radii.
>Major and minor radius in terms of povray torus syntax.
>
>torus { major_radius, minor_radius }
>
>The macro I was looking for is
>#macro elliptical_torus( x_major_radius, z_major_radius, minor_radius)
>
>I think that torus at mathworld is equivolent to:
>#macro elliptical_torus( major_radius, x_minor_radius, y_minor_radius )
>when orientated like a pov torus (x z plane)
>
>But like I said Alf, I am sure I could find a use for it.
>

What they have on that mathworld site is easy. Using their "a", "b", "c"
parameters it's just

        torus {a,b scale <1,c/b,1>}

-- 
Mike Williams
Gentleman of Leisure

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