spirals
Author Message
spirals

Does anybody know the calculation for drawing a spiral?

and or

The calculation for drawing a double helix?

Thanks Russ

(FLIBBLE-NIBLICK)

Tue, 22 Jan 2002 03:00:00 GMT
spirals

Quote:

> Does anybody know the calculation for drawing a spiral?

> and or

> The calculation for drawing a double helix?

Sure.  What kind of spiral?  The key to doing this is to use polar
(or cylindrical, for the
helix) coordinates and to make the coordinates themselves a function of,
say, t.  The double helix is almost trivial -- the radius stays constant
(independent of t), while the angle
and z component are both proportional to t.  Start the two spirals on
opposite ends of the
circle (by giving one angle an offset of 180 deg).  By varying the ratio
of the proportionality constants between angle and Z, you'll get a
"tighter" or "looser" double
helix.
The spiral simply relaxes the requirement that the radius is
constant.  It also becomes
a function (up to you to decide WHAT function) of t.

Bob Schor
Pascal Enthusiast

Tue, 22 Jan 2002 03:00:00 GMT
spirals

Quote:

> Does anybody know the calculation for drawing a spiral?

> and or

> The calculation for drawing a double helix?

Sure.  What kind of spiral?  The key to doing this is to use polar
(or cylindrical, for the
helix) coordinates and to make the coordinates themselves a function of,
say, t.  The double helix is almost trivial -- the radius stays constant
(independent of t), while the angle
and z component are both proportional to t.  Start the two spirals on
opposite ends of the
circle (by giving one angle an offset of 180 deg).  By varying the ratio
of the proportionality constants between angle and Z, you'll get a
"tighter" or "looser" double
helix.
The spiral simply relaxes the requirement that the radius is
constant.  It also becomes
a function (up to you to decide WHAT function) of t.

Bob Schor
Pascal Enthusiast

Tue, 22 Jan 2002 03:00:00 GMT
spirals
I apologize for my dual replies.  We were having a problem with our SMTP
server, and I
re-sent, assuming the first post had been lost ...

Wed, 23 Jan 2002 03:00:00 GMT
spirals

Quote:
> I apologize for my dual replies.  We were having a problem with our
SMTP
> server, and I
> re-sent, assuming the first post had been lost ...

Bob, we all make mistakes.  If this is your first, welcome to the club!

:-)

Walt.

--
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Share what you know. Learn what you don't.

Thu, 24 Jan 2002 03:00:00 GMT

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Relevant Pages
 1. Spirals 3. Spiral