Sorry, nothing so sophisticated. I have reams of documentation for the
Fleet Tenders, including a traditional table of offsets. In the Excel
spreadsheet, I have a row for each station (11 stations 0-10 plus some half
stations). The f&a location of each station appears in column A, then pairs
for height and beam of each of the offsets in columns B and up.In AutoCAD, a
script contains exactly the same text as the typing needed to do the same
thing, so you have to pay attention to constructing the command with the
points in the right order. It's basically a matter of creating a command of
the form
3dface x1,y1,z1 x2,y2,z2 x3,y3,z3 x4,y4,z4
(extra spaces inserted for emphasis -- one only is valid) Assuming x is
vertical, y is p&s, and z is f&a, then z1=z2, z3=z4, x1=x4, and x2=x3.
(Just so I don't confuse, these are not Excel RC references, but the actual
locations of the corners of the face.)

So this ends up with creating the first plane Of course, you have to
convert the numbers to text and put in the command and all the spaces and
commas. Then it's just copying in the usual Excel fashion to create all the
rest, paying attention to relative and absolute references, and so forth.

There's a certain amount of slogging needed to create the first plane and
get all the references right, but considering that it's about 350-400
points, each of which has to be entered four times (once for each plane in
which it appears, except at the ends), I can't imagine doing it by hand.

Creating a fair and good looking hull, as you're trying to do, is much
harder. Maybe, though, if you use Excel to do the math, this will help you
visualize it.

Of course the CAD packages have the advantage that the drawing that this png
http://www.mvfintry.com/pix/bowqtr800.png
was created from is a real 3d drawing, so you can rotate it in all three
planes to look at it from various angles. This is the same drawing, rotated:
http://www.mvfintry.com/pix/sternqtr800.png
and this is essentially the same, with half the hull erased on each side:
http://www.mvfintry.com/pix/flines800.png
so that it shows the traditional sections.

I will probably get around to putting up some of these on the site in .dwf
format, which is AutoCAD's 3d answer to PDF that can be viewed with
AutoCAD's free WHIP plug-in.

--
Jim Woodward
www.mvFintry.com


..
"boatdreams" wrote in message
...
Jim,
Great hull graphic! But out of curiosity...
Generating points for Fintry's hull design in Excel, did you start with
calculations for the transversals? And if so, what family of curves
would evolve so smoothly from the forward V to the mid and aft U
sections? It kind of looks like you morphed a tangent into a secant.
But how do you do that in calcs? Or did you start with the
longitudinals and then somehow connect the dots for the frames?
I'm playing with an Excel development of a one-off hull design and have
a pretty good layout using all secant frames, but a tangent in the bow
would give me just the right entry...if only I could figure out the
transition.
Any thoughts would be greatly appreciated.
boat_dreams

Jim Woodward wrote:
...
If you're going to use CAD (or any complex computer program), you have
to
... Here's Fintry, done this way:
http://www.mvfintry.com/pix/bowqtr800.png