Glenn,

You're a great contributor around here and your project all by itself is a
great inspiration. The same goes for your workmanship and all the items
you've made for your boat, so don't take this wrong. My statements below
are direct because I'm about as eloquent as a runaway freight train, but
they are not personal barbs by any means, just points of information to
consider ...made so that others won't go off with incorrect definitions:

1. NURBS are not 'conic sections'. Conic sections include the family of
curves obtained by slicing a cone with a plane (circles, ellipses,
hyperbolas, parabolas, straight lines, and single points). If you constrain
a NURB to being a quadratic in 2 dimensions (n=2, k=3), then the math
produces a conic section. NURBS are far more flexible than that. Good 2D
and 3D CAD software contains options to do just this, e.g. produce
'developable surfaces' or 'conic section curves'.

2. The Copenhagen curves are special in that they hold a special place in
history. Many feel that this particular set of curves (with monotonically
increasing curl from their inflection points) are the only curves, singly or
together, that produce certain classic lines ...sheer lines, stem lines,
etcetera. Whether everybody shares that opinion or not, there *is* value in
having these curves in DWG or DXF format as a set of references that can be
used when producing boat designs with CAD ...if you share this value
statement and desire to produce 'classic Copenhagen' lines on a boat. I own
a set myself but have not taken the time to produce them in CAD. I may
someday ...if I ever run out of things to do.


Brian D




"Glenn Ashmore" wrote in message
news:VJU%d.70764$SF.41768@lakeread08...
In that case, you could download that picture, import it into Autocad,
scale
it and trace the patterns. For refference, I have a set of 8 curves and
#43
is 24" long and #59 is 12.5" long.

Should be fairly easy to trace because, unlike French Curves they are made
up of conic sections which is exactly what the non-uniform B-spline
algorythm does.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"JP Sipponen" wrote in message
...

What would you need them for? Their purpose is for fairing a curve and
when
you are working with a CAD program the B-spline function takes their
place
and does a much better job of it..

Old friend of mine with no computer makes boats and he needs a set of
them.
They cost over 350 $ so I thought i would make them with a CNC router.

Jukkis