Not really.  You've got the spiral bit right, but a spiral doesn't have to
be 2D, it can be a helical spiral (increasing in height, constant radius).
A helix is really the path made by the end point of an unwrapping 2D shape.
Take a square for instance.  Pick the bottom right corner and swing it out
to 180 degrees with the left side, now swing this whole line out to 180
degrees to the top side and continue.  This will create a 2D path of the end
point of the unwrapping 2D shape, in the case of a square, it will look like
the side view of a sea shell.  At least that's what I was taught in graphics
class last month!  I think however that by the dictonary term you're right,
it says "A spiral of coil, such as a corkscrew".  Strange however that it
would use the word spiral in that description, because by the description of
a spiral and judging on the description it gave of a helix, a helix is
really a special type of spiral... Spiral "(1) A continuous curve moving
around a fixed point at a steadily increasing or decreasing distance, as a
watch-spring.  (2) A continuous curve winding round a central axis but
continually changing plane, as in a spiral staircase of the thread of a
screw."

So basically, a helix is a type of spiral.  But I'm open to other
interpretations.  I think what this all comes down to however is that the
original question in the thread was answered by "spiral1".  This produces
the effect needed.

--
Lance.


---
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Nieminen Mika wrote in message <3674ea52.0@news.povray.org>...
>Julius Klatte <jku### [at] hotmailcom> wrote:
>: I understand what the difference between spiral and helix is
>: for POV, but I was just wondering what (as a language thing)
>: the difference between a "spiral" and a "helix" is. I always
>: thought they meant the same thing.
>
>  Maybe I'm wrong, but this is what I have understood:
>  AFAIK: A spiral is a line on a 2D plane which can be drawn this way:
>start drawing a circle but increase the radius constantly. When you have
>made a complete 360 degrees curve, you are a little bit farther away from
>the center. Continue drawing and you get a spiral curve.
>  A helix is a 3D line instead of 2D like the spiral. You can draw it this
>way: start drawing a circle in the xy-plane, but instead of changing the
>radius, keep it constant, but increase the z-coordinate, ie. the height.
>When you have done a complete 360 degrees curve, you are still at the same
>distance from the center axis, but a little bit higher from the plane.
>Continue this way and you get a helix curve.
>  A galaxy has typically a spiral shape, while a spring has a helix shape.
>
>--
>main(i){char*_="BdsyFBThhHFBThhHFRz]NFTITQF|DJIFHQhhF";while(i=
>*_++)for(;i>1;printf("%s",i-70?i&1?"[]":" ":(i=0,"\n")),i/=2);} /*-
Warp. -*/

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