POV-Ray : Newsgroups : povray.text.tutorials : spiral : Re: spiral Server Time
20 Oct 2021 19:52:07 EDT (-0400)
  Re: spiral  
From: Mike Williams
Date: 20 Jul 2007 03:20:40
Message: <EByy$FAUEGoGFwDe@econym.demon.co.uk>
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


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