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

"Brian D" wrote in message news:Ro2Bb.270575$Dw6.918600@attbi_s02...
Scotty,

Don't be scared off. Buy some cheap 1/8" door skin and build a 1/4 scale
model. Use duct tape as your 'adhesive'.

Model my ass, that's the way I build my full size boats!
Scotty

You'll find most errors right
off. Have some fun...

Brian

"Backyard Renegade" wrote in message
m...
"Brian D" wrote in message
news:m9NAb.460002$Fm2.453789@attbi_s04...
Keep in mind that shell plate expansion (what you are doing by hand and
with
software) is one of the more challenging parts of a hull design program.
Even programs produced for more professional work, such as Rhino 3D and
ProSurf, do not do a perfect job until you learn the ins and outs and
tricks
of the trade to make it work right ...a key one being tolerance
management.
It's very easy to create an issue with tolerance stacking, especially in
an
iterative calculation like what shell plate expansion uses. You can
nearly
always tell which designers actually built the boat they sell plans to
or
not by how large the errors are in the panels. I've heard of errors as
large as 5" in a 20' boat for example. Another key is management of
curve
complexity. In a developable panel, this primarily refers to the
combination of rate of change of curvature and also the tightness
(radius)
of the curves. To be accurate in such areas, the triangulation (what
the
software is doing) either has to be very tight across the board or vary
as
it goes. You'll find that every program is 'pretty good' to a point,
then
once beyond that particular constraint, the accuracy drops off. Try
designing a boat with more gentle curves and see how it works out. If
the
software allows you to define a measurement tolerance, then lean towards
making it tighter, not looser. You can loosen the specs after you have
a
finished panel that works, but don't do it in the calculation stage
(kind of
like not rounding off in precision until you report the final answer
with
the right number of significant digits.)

So, the bottom line is: take heart, your experience is not out of the
ordinary. Look into the settings that Carlson makes available and
continue
to try different approaches until it all comes together.

Brian

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

I just got my design for a 20 footer I am building back from the
engineer (who I had go over the design a one time). I designed the
boat in Carlson and was able to shape the bulkheads there. I was
thinking about expanding the panels out and building that way but the
more I read, the more I think I might just get them out the old
fashioned way.
Scotty from SmallBoats.com

"Brian D" wrote in message news:Ro2Bb.270575$Dw6.918600@attbi_s02...
Scotty,

Don't be scared off. Buy some cheap 1/8" door skin and build a 1/4 scale
model. Use duct tape as your 'adhesive'. You'll find most errors right
off. Have some fun...

Brian

Seriously though, you will still have to take those fixes up to full
size, why not just spile the panels off the frame in the first place?
Scotty


"Backyard Renegade" wrote in message
m...
"Brian D" wrote in message
news:m9NAb.460002$Fm2.453789@attbi_s04...
Keep in mind that shell plate expansion (what you are doing by hand and
with
software) is one of the more challenging parts of a hull design program.
Even programs produced for more professional work, such as Rhino 3D and
ProSurf, do not do a perfect job until you learn the ins and outs and
tricks
of the trade to make it work right ...a key one being tolerance
management.
It's very easy to create an issue with tolerance stacking, especially in
an
iterative calculation like what shell plate expansion uses. You can
nearly
always tell which designers actually built the boat they sell plans to
or
not by how large the errors are in the panels. I've heard of errors as
large as 5" in a 20' boat for example. Another key is management of
curve
complexity. In a developable panel, this primarily refers to the
combination of rate of change of curvature and also the tightness
(radius)
of the curves. To be accurate in such areas, the triangulation (what
the
software is doing) either has to be very tight across the board or vary
as
it goes. You'll find that every program is 'pretty good' to a point,
then
once beyond that particular constraint, the accuracy drops off. Try
designing a boat with more gentle curves and see how it works out. If
the
software allows you to define a measurement tolerance, then lean towards
making it tighter, not looser. You can loosen the specs after you have
a
finished panel that works, but don't do it in the calculation stage
(kind of
like not rounding off in precision until you report the final answer
with
the right number of significant digits.)

So, the bottom line is: take heart, your experience is not out of the
ordinary. Look into the settings that Carlson makes available and
continue
to try different approaches until it all comes together.

Brian

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

I just got my design for a 20 footer I am building back from the
engineer (who I had go over the design a one time). I designed the
boat in Carlson and was able to shape the bulkheads there. I was
thinking about expanding the panels out and building that way but the
more I read, the more I think I might just get them out the old
fashioned way.
Scotty from SmallBoats.com

Sorry (I'm laughing) ...you crack me up! I was thinking of larger boats
....forgot that you tend towards light craft. Too funny ...make sure you
take the duct tape off before you sell them!

Brian

"Backyard Renegade" wrote in message
om...
"Brian D" wrote in message
news:Ro2Bb.270575$Dw6.918600@attbi_s02...
Scotty,

Don't be scared off. Buy some cheap 1/8" door skin and build a 1/4
scale
model. Use duct tape as your 'adhesive'.

Model my ass, that's the way I build my full size boats!
Scotty

You'll find most errors right
off. Have some fun...

Brian

"Backyard Renegade" wrote in message
m...
"Brian D" wrote in message
news:m9NAb.460002$Fm2.453789@attbi_s04...
Keep in mind that shell plate expansion (what you are doing by hand
and
with
software) is one of the more challenging parts of a hull design
program.
Even programs produced for more professional work, such as Rhino 3D
and
ProSurf, do not do a perfect job until you learn the ins and outs
and
tricks
of the trade to make it work right ...a key one being tolerance
management.
It's very easy to create an issue with tolerance stacking,
especially in
an
iterative calculation like what shell plate expansion uses. You can
nearly
always tell which designers actually built the boat they sell plans
to
or
not by how large the errors are in the panels. I've heard of errors
as
large as 5" in a 20' boat for example. Another key is management of
curve
complexity. In a developable panel, this primarily refers to the
combination of rate of change of curvature and also the tightness
(radius)
of the curves. To be accurate in such areas, the triangulation
(what
the
software is doing) either has to be very tight across the board or
vary
as
it goes. You'll find that every program is 'pretty good' to a
point,
then
once beyond that particular constraint, the accuracy drops off. Try
designing a boat with more gentle curves and see how it works out.
If
the
software allows you to define a measurement tolerance, then lean
towards
making it tighter, not looser. You can loosen the specs after you
have
a
finished panel that works, but don't do it in the calculation stage
(kind of
like not rounding off in precision until you report the final answer
with
the right number of significant digits.)

So, the bottom line is: take heart, your experience is not out of
the
ordinary. Look into the settings that Carlson makes available and
continue
to try different approaches until it all comes together.

Brian

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

I just got my design for a 20 footer I am building back from the
engineer (who I had go over the design a one time). I designed the
boat in Carlson and was able to shape the bulkheads there. I was
thinking about expanding the panels out and building that way but the
more I read, the more I think I might just get them out the old
fashioned way.
Scotty from SmallBoats.com

Card stock is a lot cheaper to buy and has the stiffness that is easy to
work with.

Brian

It's a chicken and the egg problem. Your frames won't give you panels
unless they define a developable surface so unless you keep it simple and
are willing to do some trial and error, then spiling to the frames is
somewhat limited in value. The book you find most recommended (and there
are others, as Jacques and others pointed out, including an old mechanical
engineering text on drafting that I happen to own) is the book by S. S.
Rable. I believe it's still for sale. Look for "Ship and Aircraft Fairing
and Development." It's an older text so some of the terminology or wording
can be a little confusing but if you work the examples as you go through it,
you'll learn the process. I find it much less error prone to do the work
with AutoCAD rather than by hand ...pencil-width errors when doing the
necessary triangulation can add up to too much of an error when doing
complex plate expansions, but CAD uses exact calculations (measurements) and
the line width is has nothing to do with accuracy.

I disagree with Jacques on trying out Rhino 3D (around $1100). I mean I
agree a little, but disagree if you are planning on doing anything other
than a "look and feel" trial of Rhino. The surface techniques take some
time to learn if you are to get it right and can be darn frustrating if you
don't take the time to learn the ins and outs. The learning process
typically takes a number of months (like any good CAD tool). In summary
though, Rhino will let you define a surface and then constrain it to be
developable (conic sections, cylinders, flat) and can then unroll it to
produce flat panels that will work. You have to be careful with tolerances
too, else the panels will still produce gaps in the finished boat. Note
that Rhino is a general solid modeling tool, not really optimized for hull
design. ProSurf is fairly straight forward to learn and they let you
download it for free too. It *is* designed for hull development and has
tools that Rhino does not include that make the process easier and more
accurate. It's about $800, but the trial version will let you save 16 times
for free. If you are a student basically anywhere, I believe both outfits
will reduce their prices to around $300 though and that's for fully
functional software.

Brian


"Backyard Renegade" wrote in message
om...
"Brian D" wrote in message
news:Ro2Bb.270575$Dw6.918600@attbi_s02...
Scotty,

Don't be scared off. Buy some cheap 1/8" door skin and build a 1/4
scale
model. Use duct tape as your 'adhesive'. You'll find most errors right
off. Have some fun...

Brian

Seriously though, you will still have to take those fixes up to full
size, why not just spile the panels off the frame in the first place?
Scotty


"Backyard Renegade" wrote in message
m...
"Brian D" wrote in message
news:m9NAb.460002$Fm2.453789@attbi_s04...
Keep in mind that shell plate expansion (what you are doing by hand
and
with
software) is one of the more challenging parts of a hull design
program.
Even programs produced for more professional work, such as Rhino 3D
and
ProSurf, do not do a perfect job until you learn the ins and outs
and
tricks
of the trade to make it work right ...a key one being tolerance
management.
It's very easy to create an issue with tolerance stacking,
especially in
an
iterative calculation like what shell plate expansion uses. You can
nearly
always tell which designers actually built the boat they sell plans
to
or
not by how large the errors are in the panels. I've heard of errors
as
large as 5" in a 20' boat for example. Another key is management of
curve
complexity. In a developable panel, this primarily refers to the
combination of rate of change of curvature and also the tightness
(radius)
of the curves. To be accurate in such areas, the triangulation
(what
the
software is doing) either has to be very tight across the board or
vary
as
it goes. You'll find that every program is 'pretty good' to a
point,
then
once beyond that particular constraint, the accuracy drops off. Try
designing a boat with more gentle curves and see how it works out.
If
the
software allows you to define a measurement tolerance, then lean
towards
making it tighter, not looser. You can loosen the specs after you
have
a
finished panel that works, but don't do it in the calculation stage
(kind of
like not rounding off in precision until you report the final answer
with
the right number of significant digits.)

So, the bottom line is: take heart, your experience is not out of
the
ordinary. Look into the settings that Carlson makes available and
continue
to try different approaches until it all comes together.

Brian

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

I just got my design for a 20 footer I am building back from the
engineer (who I had go over the design a one time). I designed the
boat in Carlson and was able to shape the bulkheads there. I was
thinking about expanding the panels out and building that way but the
more I read, the more I think I might just get them out the old
fashioned way.
Scotty from SmallBoats.com

"Brian D" wrote in message news:MClBb.486707$Fm2.472295@attbi_s04...
It's a chicken and the egg problem. Your frames won't give you panels
unless they define a developable surface so unless you keep it simple and
are willing to do some trial and error, then spiling to the frames is
somewhat limited in value. The book you find most recommended (and there
are others, as Jacques and others pointed out, including an old mechanical
engineering text on drafting that I happen to own) is the book by S. S.
Rable. I believe it's still for sale. Look for "Ship and Aircraft Fairing
and Development." It's an older text so some of the terminology or wording
can be a little confusing but if you work the examples as you go through it,
you'll learn the process. I find it much less error prone to do the work
with AutoCAD rather than by hand ...pencil-width errors when doing the
necessary triangulation can add up to too much of an error when doing
complex plate expansions, but CAD uses exact calculations (measurements) and
the line width is has nothing to do with accuracy.

I disagree with Jacques on trying out Rhino 3D (around $1100). I mean I
agree a little, but disagree if you are planning on doing anything other
than a "look and feel" trial of Rhino. The surface techniques take some
time to learn if you are to get it right and can be darn frustrating if you
don't take the time to learn the ins and outs. The learning process
typically takes a number of months (like any good CAD tool). In summary
though, Rhino will let you define a surface and then constrain it to be
developable (conic sections, cylinders, flat) and can then unroll it to
produce flat panels that will work. You have to be careful with tolerances
too, else the panels will still produce gaps in the finished boat. Note
that Rhino is a general solid modeling tool, not really optimized for hull
design. ProSurf is fairly straight forward to learn and they let you
download it for free too. It *is* designed for hull development and has
tools that Rhino does not include that make the process easier and more
accurate. It's about $800, but the trial version will let you save 16 times
for free. If you are a student basically anywhere, I believe both outfits
will reduce their prices to around $300 though and that's for fully
functional software.

Brian



I am extremely proficient with several CAD programs, will not bore you
with resume'. But when I build my smallboats I mostly find myself
building the boat and getting out the panels the old fashioned way and
then later put them to cad, and then only for repeatability. I start
with bulkheads, sometimes run chine seams, and then make cheap
templates or use a spiling plank to get the pieces out, one time, full
size, even for small stitch and tape boats.

The boat I am finally building for myself, some of you may remember
discussion of a 20 foot skiff, will have 6 planks. I designed it in
Carlson Hulls, mostly so I could get a 3D look at it and some simple
numbers to compare as I shaped the hull. Eventually though, when I
build it, I will probably revert to more traditional ways of getting
out the planks once the station molds/bulkheads and seam battens are
in place.

Let's say it takes the average person 8-12 hours solid time to learn a
new program to the point where they can use it to get out panels, and
then say another 4-8 to either design or transfer over a boat hull and
spit out those expanded panels. You have 16 hours in and you have cut
nothing and these time guestimates are all probably very low as these
software programs are mostly directed toward those with formal
drafting experience/education. Remembering that I am talking about a
simple 6 plank 20 foot boat, (and Santa is not likely to bring me a
CNC machine) I dare say with a few sheets of luan or some battens,
ruler, pencil, skill saw, and a good days work, I could already have
all my panels cut out. No fancy software, no $800 pricetag, just some
basic math and a little common sense... I dunno, I am still not
convinced, Scotty

Yes, ProSurf is very good, it's the old Nautilus and it handles surface
development well but it is not easier to learn than Rhino.
We can all agree that whatever method you use, it will take some learning.
--
Jacques
http://www.bateau.com

"Brian D" wrote in message
news:MClBb.486707$Fm2.472295@attbi_s04...
It's a chicken and the egg problem. Your frames won't give you panels
unless they define a developable surface so unless you keep it simple and
are willing to do some trial and error, then spiling to the frames is
somewhat limited in value. The book you find most recommended (and there
are others, as Jacques and others pointed out, including an old mechanical
engineering text on drafting that I happen to own) is the book by S. S.
Rable. I believe it's still for sale. Look for "Ship and Aircraft
Fairing
and Development." It's an older text so some of the terminology or
wording
can be a little confusing but if you work the examples as you go through
it,
you'll learn the process. I find it much less error prone to do the work
with AutoCAD rather than by hand ...pencil-width errors when doing the
necessary triangulation can add up to too much of an error when doing
complex plate expansions, but CAD uses exact calculations (measurements)
and
the line width is has nothing to do with accuracy.

I disagree with Jacques on trying out Rhino 3D (around $1100). I mean I
agree a little, but disagree if you are planning on doing anything other
than a "look and feel" trial of Rhino. The surface techniques take some
time to learn if you are to get it right and can be darn frustrating if
you
don't take the time to learn the ins and outs. The learning process
typically takes a number of months (like any good CAD tool). In summary
though, Rhino will let you define a surface and then constrain it to be
developable (conic sections, cylinders, flat) and can then unroll it to
produce flat panels that will work. You have to be careful with
tolerances
too, else the panels will still produce gaps in the finished boat. Note
that Rhino is a general solid modeling tool, not really optimized for hull
design. ProSurf is fairly straight forward to learn and they let you
download it for free too. It *is* designed for hull development and has
tools that Rhino does not include that make the process easier and more
accurate. It's about $800, but the trial version will let you save 16
times
for free. If you are a student basically anywhere, I believe both outfits
will reduce their prices to around $300 though and that's for fully
functional software.

Brian


"Backyard Renegade" wrote in message
om...
"Brian D" wrote in message
news:Ro2Bb.270575$Dw6.918600@attbi_s02...
Scotty,

Don't be scared off. Buy some cheap 1/8" door skin and build a 1/4
scale
model. Use duct tape as your 'adhesive'. You'll find most errors
right
off. Have some fun...

Brian

Seriously though, you will still have to take those fixes up to full
size, why not just spile the panels off the frame in the first place?
Scotty


"Backyard Renegade" wrote in message
m...
"Brian D" wrote in message
news:m9NAb.460002$Fm2.453789@attbi_s04...
Keep in mind that shell plate expansion (what you are doing by
hand
and
with
software) is one of the more challenging parts of a hull design
program.
Even programs produced for more professional work, such as Rhino
3D
and
ProSurf, do not do a perfect job until you learn the ins and outs
and
tricks
of the trade to make it work right ...a key one being tolerance
management.
It's very easy to create an issue with tolerance stacking,
especially in
an
iterative calculation like what shell plate expansion uses. You
can
nearly
always tell which designers actually built the boat they sell
plans
to
or
not by how large the errors are in the panels. I've heard of
errors
as
large as 5" in a 20' boat for example. Another key is management
of
curve
complexity. In a developable panel, this primarily refers to the
combination of rate of change of curvature and also the tightness
(radius)
of the curves. To be accurate in such areas, the triangulation
(what
the
software is doing) either has to be very tight across the board or
vary
as
it goes. You'll find that every program is 'pretty good' to a
point,
then
once beyond that particular constraint, the accuracy drops off.
Try
designing a boat with more gentle curves and see how it works out.
If
the
software allows you to define a measurement tolerance, then lean
towards
making it tighter, not looser. You can loosen the specs after you
have
a
finished panel that works, but don't do it in the calculation
stage
(kind of
like not rounding off in precision until you report the final
answer
with
the right number of significant digits.)

So, the bottom line is: take heart, your experience is not out of
the
ordinary. Look into the settings that Carlson makes available and
continue
to try different approaches until it all comes together.

Brian

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

I just got my design for a 20 footer I am building back from the
engineer (who I had go over the design a one time). I designed the
boat in Carlson and was able to shape the bulkheads there. I was
thinking about expanding the panels out and building that way but
the
more I read, the more I think I might just get them out the old
fashioned way.
Scotty from SmallBoats.com

Good point: if you plan to build only one boat, it is not worth spending all
that time learning CAD. Trial and error is, in that case, a better method.
You can start with a cardboard scaled model and fine tune the panels full
size with cheap plywood.

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

"Backyard Renegade" wrote in message
om...
"Brian D" wrote in message
news:MClBb.486707$Fm2.472295@attbi_s04...
It's a chicken and the egg problem. Your frames won't give you panels
unless they define a developable surface so unless you keep it simple
and
are willing to do some trial and error, then spiling to the frames is
somewhat limited in value. The book you find most recommended (and
there
are others, as Jacques and others pointed out, including an old
mechanical
engineering text on drafting that I happen to own) is the book by S. S.
Rable. I believe it's still for sale. Look for "Ship and Aircraft
Fairing
and Development." It's an older text so some of the terminology or
wording
can be a little confusing but if you work the examples as you go through
it,
you'll learn the process. I find it much less error prone to do the
work
with AutoCAD rather than by hand ...pencil-width errors when doing the
necessary triangulation can add up to too much of an error when doing
complex plate expansions, but CAD uses exact calculations (measurements)
and
the line width is has nothing to do with accuracy.

I disagree with Jacques on trying out Rhino 3D (around $1100). I mean I
agree a little, but disagree if you are planning on doing anything other
than a "look and feel" trial of Rhino. The surface techniques take some
time to learn if you are to get it right and can be darn frustrating if
you
don't take the time to learn the ins and outs. The learning process
typically takes a number of months (like any good CAD tool). In summary
though, Rhino will let you define a surface and then constrain it to be
developable (conic sections, cylinders, flat) and can then unroll it to
produce flat panels that will work. You have to be careful with
tolerances
too, else the panels will still produce gaps in the finished boat. Note
that Rhino is a general solid modeling tool, not really optimized for
hull
design. ProSurf is fairly straight forward to learn and they let you
download it for free too. It *is* designed for hull development and has
tools that Rhino does not include that make the process easier and more
accurate. It's about $800, but the trial version will let you save 16
times
for free. If you are a student basically anywhere, I believe both
outfits
will reduce their prices to around $300 though and that's for fully
functional software.

Brian



I am extremely proficient with several CAD programs, will not bore you
with resume'. But when I build my smallboats I mostly find myself
building the boat and getting out the panels the old fashioned way and
then later put them to cad, and then only for repeatability. I start
with bulkheads, sometimes run chine seams, and then make cheap
templates or use a spiling plank to get the pieces out, one time, full
size, even for small stitch and tape boats.

The boat I am finally building for myself, some of you may remember
discussion of a 20 foot skiff, will have 6 planks. I designed it in
Carlson Hulls, mostly so I could get a 3D look at it and some simple
numbers to compare as I shaped the hull. Eventually though, when I
build it, I will probably revert to more traditional ways of getting
out the planks once the station molds/bulkheads and seam battens are
in place.

Let's say it takes the average person 8-12 hours solid time to learn a
new program to the point where they can use it to get out panels, and
then say another 4-8 to either design or transfer over a boat hull and
spit out those expanded panels. You have 16 hours in and you have cut
nothing and these time guestimates are all probably very low as these
software programs are mostly directed toward those with formal
drafting experience/education. Remembering that I am talking about a
simple 6 plank 20 foot boat, (and Santa is not likely to bring me a
CNC machine) I dare say with a few sheets of luan or some battens,
ruler, pencil, skill saw, and a good days work, I could already have
all my panels cut out. No fancy software, no $800 pricetag, just some
basic math and a little common sense... I dunno, I am still not
convinced, Scotty

Danm, Scotty don't get that thread started again! :-)

"Backyard Renegade" wrote in message
om...
"Brian D" wrote in message
news:Ro2Bb.270575$Dw6.918600@attbi_s02...
Scotty,

Don't be scared off. Buy some cheap 1/8" door skin and build a 1/4
scale
model. Use duct tape as your 'adhesive'.

Model my ass, that's the way I build my full size boats!
Scotty

You'll find most errors right
off. Have some fun...

Brian

"Backyard Renegade" wrote in message
m...
"Brian D" wrote in message
news:m9NAb.460002$Fm2.453789@attbi_s04...
Keep in mind that shell plate expansion (what you are doing by hand
and
with
software) is one of the more challenging parts of a hull design
program.
Even programs produced for more professional work, such as Rhino 3D
and
ProSurf, do not do a perfect job until you learn the ins and outs
and
tricks
of the trade to make it work right ...a key one being tolerance
management.
It's very easy to create an issue with tolerance stacking,
especially in
an
iterative calculation like what shell plate expansion uses. You can
nearly
always tell which designers actually built the boat they sell plans
to
or
not by how large the errors are in the panels. I've heard of errors
as
large as 5" in a 20' boat for example. Another key is management of
curve
complexity. In a developable panel, this primarily refers to the
combination of rate of change of curvature and also the tightness
(radius)
of the curves. To be accurate in such areas, the triangulation
(what
the
software is doing) either has to be very tight across the board or
vary
as
it goes. You'll find that every program is 'pretty good' to a
point,
then
once beyond that particular constraint, the accuracy drops off. Try
designing a boat with more gentle curves and see how it works out.
If
the
software allows you to define a measurement tolerance, then lean
towards
making it tighter, not looser. You can loosen the specs after you
have
a
finished panel that works, but don't do it in the calculation stage
(kind of
like not rounding off in precision until you report the final answer
with
the right number of significant digits.)

So, the bottom line is: take heart, your experience is not out of
the
ordinary. Look into the settings that Carlson makes available and
continue
to try different approaches until it all comes together.

Brian

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

I just got my design for a 20 footer I am building back from the
engineer (who I had go over the design a one time). I designed the
boat in Carlson and was able to shape the bulkheads there. I was
thinking about expanding the panels out and building that way but the
more I read, the more I think I might just get them out the old
fashioned way.
Scotty from SmallBoats.com