POV-Ray : Newsgroups : povray.text.tutorials : spiral : Re: spiral Server Time26 Feb 2024 07:12:24 EST (-0500)
 Re: spiral
 From: Mike Williams Date: 20 Jul 2007 03:20:40 Message:
```
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Wasn't it zeroin23 who wrote:
>Hay is this a helix?

The path of a thin strip of that is a helix, e.g. if you set the limits
to  <pi,0> <8*pi,0.01>  then you get a thin line that follows a helical
path.

The problem is that the width of the ribbon consists of points that are
always in the positive x and y directions, which isn't like anything
you'd expect.

This gives a ribbon that has a surface parallel to the axis. The
ribbon's width is in the z direction.
function {sin(u)}
function {cos(u)}
function {u+v}

This gives a ribbon that has a surface that is perpendicular to the
axis. The ribbon's width is outwards from the centre in the direction
<sin(u),cos(v)>
function {sin(u)*(1+v)}
function {cos(u)*(1+v)}
function {u}

--
Mike Williams
Gentleman of Leisure
```