I have a table of offsets for a hull design I would like to build. Does
anyone know of any softawre that I can use to plot these with? No big deal
if I have to do it by hand, but thought software might be interesting.
Thank you.
Ed

Ed,
Past experience shows that a table of offsets is incredibly painful (if not
impossible) to loft on a computer.
Your best bet is to get old of Alan Vaitses' book "Lofting" and do it the old
fashioned way.
By doing this, you will gain insight into the shape required that will stand
you in good stead as you build. Phrases like "Ahah! I had to bump this
station on the lofting" will run through your mind as you ponder on the
impossibility of getting a plank to fit just right. ;-)

Steve "horses for courses"
Stephen C. Baker - Yacht Designer
http://members.aol.com/SailDesign/pr...cbweb/home.htm

Ed.
You`ll find it easier and more useful to do it by hand, it`s pretty simple
to do, George Buehler`s "Backyard Boatbuilding" covers it, and is good-
though somwhat idiosyncratic- reading into the bargain :-).
HTH
Bob larder
Ed Jackson wrote:
I have a table of offsets for a hull design I would like to build.
Does anyone know of any softawre that I can use to plot these with?
No big deal if I have to do it by hand, but thought software might be
interesting. Thank you.
Ed

Ed Jackson wrote in
7.136:

I have a table of offsets for a hull design I would like to build.
Does anyone know of any softawre that I can use to plot these with? No
big deal if I have to do it by hand, but thought software might be
interesting. Thank you.
Ed

Thank you for the replies. I suspected what you both say is true. I'll just
do it the old fashioned way.
Thank you.
Ed

"Ed Jackson" wrote in message
7.136...
Ed Jackson wrote in
7.136:

I have a table of offsets for a hull design I would like to build.
Does anyone know of any softawre that I can use to plot these with? No
big deal if I have to do it by hand, but thought software might be
interesting. Thank you.
Ed

Thank you for the replies. I suspected what you both say is true. I'll
just
do it the old fashioned way.
Thank you.
Ed

try the free download of Rhino. (Google for Rhino 3d)
A big piece of software... and i belive the free version is the full
package, but only saves so many times.
I bought it some years ago and use it almost daily for designing things like
cabin steps... working out bevels and cutting lists.
I agree with the opinions here that doing it by hand is a usefull way... but
I Would never work without Rhino

It might not be feasible to loft the boat with a computer program but you
can enter the table of offsets into hull design programs to look at a 3D
wire frame model on the screen, and to get a bunch of calculated numbers
for the hull. I've used two free hull design programs, the first for
MS-DOS although there might be a free Windows version by now at
www.bludepeterdesign.com, and the second for Windows restricted to boats
built our of plywood panels which will plot the the panels for cutting out
of sheets of plywood at www.carlsondesign.com. Both programs require some
time and patience to learn how to use.

Ed Jackson ) writes:
I have a table of offsets for a hull design I would like to build. Does
anyone know of any softawre that I can use to plot these with? No big deal
if I have to do it by hand, but thought software might be interesting.
Thank you.
Ed


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I should have mentioned that there is a list of computer programs at
www.boat-links.com.

Ed Jackson ) writes:
I have a table of offsets for a hull design I would like to build. Does
anyone know of any softawre that I can use to plot these with? No big deal
if I have to do it by hand, but thought software might be interesting.
Thank you.
Ed


--
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William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-FreeNet email must have "notspam" in subject or it's returned

James says:

try the free download of Rhino. (Google for Rhino 3d)

snip

... but
I Would never work without Rhino

I use Rhino every day, but would never try it for this purpose. The shpaes
produced are just not fair. For a quickie guestimate of numbers, it may be
fine, but that is it.
Here's an example, kinda...
I found this old lines plan in a book by Phillips-Birt:

http://www.boatdesign.net/gallery/sh...ize/big/sort/1
/cat/500

After 2 hours with Rhino and a tracing program, I had something that looked
right in profile, but had a surface so unfair that you could see the "planks"
where Rhino had tried to fit a surface.

Two more hours in AutoShip, woring "off-surface", it had faired into this:

http://www.boatdesign.net/gallery/sh...ort/1/size/big
/cat/500/page/

I'm not going ot kid you that those lines are exact, but they are extremely
close.

Eventually, my imagination got the better of me and I stuck on a deck and rig:
http://www.boatdesign.net/gallery/sh...ort/1/cat/500/
page/1

With just Rhino, it would be another "failed project" on the back-burner.

Steve
Stephen C. Baker - Yacht Designer
http://members.aol.com/SailDesign/pr...cbweb/home.htm

"Ed Jackson" wrote in message
7.136...
I have a table of offsets for a hull design I would like to build. Does
anyone know of any softawre that I can use to plot these with? No big deal
if I have to do it by hand, but thought software might be interesting.

You can do it with any cad program. Just enter the points of offset for
every station on a different z-plane, spaced apart by the amount stated in
the offset table or building description. Most cad programs offer a single
point entity, which can often be set to appear as a little cross. Then, as a
simulation of a batten used on a real lofting floor, you can use a spline or
bezier curve to try to fit a smooth line between the points of a single
station. I found splines to be the easiest. After a while you get the right
feeling for the number of control points to start with. Mostly you can do it
with tree control points for a round-bilge design, but in keel or transom
areas you might need 4 or even 5.

After you entered the curves for every station, you'll have a nice 3d wire
model of your boat. Then rotate it and start drawing the buttock points and
draw their splines. Then you'll often notice that in order to the the
buttocks smooth, you'll have to modify the station curves again. Kind of an
iterative process. And at last, you can do the same procedure for the
diagonals as well.

Meindert

If this a stitch and glue type boat...

Rhino would work for this but I'd use the offsets as reference points
only. If you limit the number of control points of a curve to 3-5, Rhino
will produce a fair surface from those curves. There are limts to that
of course. When you make a curve or surface in Rhino (and similar
applications) the fewer amount of control points you use, the fairing
the curve/surface will be.

Set up the offsets and then redraw the curves and re-position the
control points so you get close, but don't force them to match
perfectly. Rhino does a nice job forming "natural" curves.

--
Matt Langenfeld
JEM Watercraft
http://www.jemwatercraft.com


Stephen Baker wrote:
James says:


try the free download of Rhino. (Google for Rhino 3d)


snip

... but
I Would never work without Rhino


I use Rhino every day, but would never try it for this purpose. The shpaes
produced are just not fair. For a quickie guestimate of numbers, it may be
fine, but that is it.
Here's an example, kinda...
I found this old lines plan in a book by Phillips-Birt:

http://www.boatdesign.net/gallery/sh...ize/big/sort/1
/cat/500

After 2 hours with Rhino and a tracing program, I had something that looked
right in profile, but had a surface so unfair that you could see the "planks"
where Rhino had tried to fit a surface.

Two more hours in AutoShip, woring "off-surface", it had faired into this:

http://www.boatdesign.net/gallery/sh...ort/1/size/big
/cat/500/page/

I'm not going ot kid you that those lines are exact, but they are extremely
close.

Eventually, my imagination got the better of me and I stuck on a deck and rig:
http://www.boatdesign.net/gallery/sh...ort/1/cat/500/
page/1

With just Rhino, it would be another "failed project" on the back-burner.

Steve
Stephen C. Baker - Yacht Designer
http://members.aol.com/SailDesign/pr...cbweb/home.htm