The Carlson program develops panels correctly but that doesn't mean that
those panels are developable.
Let's explain: the development method is simple, the program divides a panel
in a bunch of parallelograms and then unroll them BUT that doesn't mean that
the surface is developable.
A developable surface must fulfill some conditions: a cone is developable, a
panel made of cones is developable but the Carlson program does not check
that.
There is another program with that flaw, Plyboats.

Good programs like Rhino, Prolines, the old Nautilus and many others will
create a developable surface that fills some conditions and can be developed
within certain limits. All the ones I know are based on the Kilgore
algorithm. Through an iteration process they check for ruling lines:
straight lines that are included on that surface and run from one edge to
the other without intersecting. There is more to it but that is the basic
problem. You must create a developable surface first. It is a much more
complicated task than to develop the panel.
A test is to design a hull with some nice curvature at the bow then cut
stations through it. If the sections close to the bow show stations with
straight sides, then the program does not do a proper job because that part
of the panels should be generated by cones.
Over the years I wrote about that in this group several times: the Carlson
program is good if you start with a hull that is developable. It is a valid
tool to scale up and down an existing boat, create patterns etc. It can even
be used to design a very simple developable hull like one with cylindrical
panels, "a la Bolger", all station sides parallel.
Who said you get what you pay for?

--
Jacques
http://www.bateau.com



"William R. Watt" wrote in message
...
Has anyone sucessfully built a boat out of unfolded panels from this hard
chine design program?

I set up stations and made a cardboard scale model of a boat by wrapping
the cardboard around some frames, marking, unfolding, and cutting. Then I
put the offsets into the Carlson program and used the "Patterns/Nesting"
feature to arrange the panels on sheets of plywood and print out points
for hand plotting. I plotted and cut the panels from cardboard, same scale
as the model, and taped the cutouts togehter sticth-and-tape style. The
result isn't the same as the model. There is a big gap at the stem, the
topside panels are 25% wider, and the it just doesn't fit the frames.

(I've been back seeing if I can alter the offests to get a better fit and
find the auto spline makign S-curves in the keel at the stem. Very
strange.)

Am wondering if others have got good unfolded panels from the program.

(The boat is the 15ft solo cruiser design I've been documenting under
"Boats" on my website.)


--
--------------------------------------------------------------------------
----
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

"Jacques Mertens" ) writes:
The Carlson program develops panels correctly but that doesn't mean that
those panels are developable.

I've seen the paper and pencil method of looking for the apex of curvature
in a couple of boatbuilding books, TF Jones for example. For the design
I'm working with constant bevels restrict the bend to one plane. As you
mentioned below I eyeball the pictures displayed on the computer screen to
make sure the station lines are parallel (no twist). Avoiding twist in the
panels at the stem shortens the waterline length but that's a (small)
price I pay for simplicity in design and construction. All I have to worry
about is that the radius of curvature is not to tight for the thickness of
the plywood to bend to. Admittedly I haven't done any radius calcutations.
With a bow half angle of 32 deg I think its okay. One more thing to put on
the "todo" list.

All the ones I know are based on the Kilgore
algorithm. Through an iteration process they check for ruling lines:
straight lines that are included on that surface and run from one edge to
the other without intersecting. There is more to it but that is the basic
problem.

Thanks. I've written down the name and will look for more info as I would
like to learn how it's done.

Over the years I wrote about that in this group several times: the Carlson
program is good if you start with a hull that is developable. It is a valid
tool to scale up and down an existing boat, create patterns etc.

Yes, all I want from the Carlson program are the plotting points for the
plywood panels on the sheets of plywood. I used the Blue Peter program
initially to flesh out the hull with stations (the program rounds the
chines as you ask it to insert more stations) and to do the design
calculations, then printed out the offsets and typed them into the Carslon
program. I naively expected to get accurate plotting points with a couple
of clicks of the mouse.


--
------------------------------------------------------------------------------
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

How about trying the free version of Rhino: rhino3d.com.
You can't save but you'll see what it does.
The command to create developable surfaces is in /surfaces/loft/developable.
Maybe it will accept to import your current model, that way you can see
where the problem is.


--
Jacques
http://www.bateau.com

"William R. Watt" wrote in message
...
"Jacques Mertens" ) writes:
The Carlson program develops panels correctly but that doesn't mean that
those panels are developable.

I've seen the paper and pencil method of looking for the apex of curvature
in a couple of boatbuilding books, TF Jones for example. For the design
I'm working with constant bevels restrict the bend to one plane. As you
mentioned below I eyeball the pictures displayed on the computer screen to
make sure the station lines are parallel (no twist). Avoiding twist in the
panels at the stem shortens the waterline length but that's a (small)
price I pay for simplicity in design and construction. All I have to worry
about is that the radius of curvature is not to tight for the thickness of
the plywood to bend to. Admittedly I haven't done any radius calcutations.
With a bow half angle of 32 deg I think its okay. One more thing to put on
the "todo" list.

All the ones I know are based on the Kilgore
algorithm. Through an iteration process they check for ruling lines:
straight lines that are included on that surface and run from one edge
to
the other without intersecting. There is more to it but that is the
basic
problem.

Thanks. I've written down the name and will look for more info as I would
like to learn how it's done.

Over the years I wrote about that in this group several times: the
Carlson
program is good if you start with a hull that is developable. It is a
valid
tool to scale up and down an existing boat, create patterns etc.

Yes, all I want from the Carlson program are the plotting points for the
plywood panels on the sheets of plywood. I used the Blue Peter program
initially to flesh out the hull with stations (the program rounds the
chines as you ask it to insert more stations) and to do the design
calculations, then printed out the offsets and typed them into the Carslon
program. I naively expected to get accurate plotting points with a couple
of clicks of the mouse.


--
--------------------------------------------------------------------------
----
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