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Carlson Hull program
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 |
Carlson Hull program
I have not built a boat from this program but I did build a small model
once. I printed the expanded panels on my printer onto stiff paper and cut them out and taped them together and everything seemed to fit together pretty much the way it should have. Never built anything from the offsets table though. I have noticed some weirdness up by the bow when fooling around with this program. Are you sure you locked in the position of your bulkheads before doing the patterns/nesting? Numbers semed to shift around otherwise. Let's face it, it almost works and the price is right but I never could get beyond the model stage though. But I think it could be done. William R. Watt wrote: 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 |
Carlson Hull program
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 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 |
Carlson Hull program
I have used this for a couple of years for my students in an Intro to Nav
Arch class. They use it to develop a 3-view (plan, profile, body plan) drawing, as well as small models. My observation is that the unwrapping is based on a geodesic approach (i.e., attached triangles), not a developable surface (i.e., unwrapped conic sections). As you get more curvature, the geodesic can underpredict the real unwrapped length of the surface. Having said that, I've never seen more than a small gap at the stem. We usually plot these via the DXF - have you tried comparing plots from the nesting and DXF through a CAD program? The DXF/CAD approach has the benefit of showing the BHEAD locations on the CHINE and DECK plots. This is very valuable with the proper alignment of pieces. One other FYI - the DXF format exported by this program is not compatible with all CAD programs. I've had good success with TurboCAD, Rhino and the Voloview Express viewer. I'm sure there are others. Regards, Don Donald M. MacPherson VP Technical Director HydroComp, Inc. http://www.hydrocompinc.com [2004 Propeller Seminar - January 16th in Tampa, Florida.] "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 |
Carlson Hull program
"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 |
Carlson Hull program
"D MacPherson" ) writes:
..My observation is that the unwrapping is based on a geodesic approach (i.e., attached triangles), not a developable surface (i.e., unwrapped conic sections). yes, I made a silly mistake in my first attempt at this boat of having the lowest point midships adn the widest point somewhat further aft, a shape to which plywood would not confrom. Neither the BluePeter nor the Carlson program complained. I knew better but was not thinking. So then I made the carboard model the old fashioned way to check before keying the offsets into the two programs to do the calculations and get the unfolded plotting points for the panels. I know designers use computers to calculate the shape of unfolded plywood panels and transfer the points to a computer controlled cutting board. I've seen advertisments on the Internet from companies like Chesepeak(?) Ligth Craft who sell kayak kits made this way. Since Greg Carlson sells cutter/plotters and his program produces a file for his cutter/plotters then I figure there should be some way I can get the program to produce accurate plotting points. Having said that, I've never seen more than a small gap at the stem. I've given myself the challenge of attempting a constant bevel which is making the stem a bit tricky on the small scale drawing on the computer screen. We usually plot these via the DXF - have you tried comparing plots from the nesting and DXF through a CAD program? oh no, I have to learn how to use anoother computer program? :) BHW: I've found it easier to use the Patterns/Nesting output because all the files have negative values for plotting points which I haven't been able to figure out. One other FYI - the DXF format exported by this program is not compatible with all CAD programs. I've had good success with TurboCAD, Rhino and the Voloview Express viewer. I'm sure there are others. I can display the DXF images with the program that came with the flat bed scanner I use. They look okay, just like the images displayed by the program itself. Havent' figured out yet how those images relate to the problems I've had with the plotting points. I tried again last night producign a new file of plotting points, drawign and cutting the panels, and taping them together. I still have more work to do on this. I could use teh old fashioned way but am determined to learn how to do it on the computer. BTW2: I make the panels pretty quickly by taping 2 letter sized sheets of paper together which gives 16" for the 16' of two sheets of plywood, plotting and joing the points (straight lines with a ruler is okay for this), putting duct tape over the back of ach panel outline for some stiffness, then cutting out the panel with scissors, and taping teh panels together on the duct tape side with small pieces of cello tape. The duct tape makes it easier to move the cello tape, no tearing of paper. Thanks to everyone for the advice. I'll keep at it. -- ------------------------------------------------------------------------------ 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 |
Carlson Hull program
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 "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 |
Carlson Hull program
Try printing onto trimmed manila folders. They give enough stiffness and
bend nicely. It helps to have a straight-feed printer, though. (The students use a Laserjet for this.) Regards, Don Donald M. MacPherson VP Technical Director HydroComp, Inc. http://www.hydrocompinc.com tel (603)868-3344 fax (603)868-3366 2004 Propeller Seminar - January 16th in Tampa, Florida. http://www.hydrocompinc.com/support/...lerSeminar.htm "William R. Watt" wrote in message ... "D MacPherson" ) writes: snip... BTW2: I make the panels pretty quickly by taping 2 letter sized sheets of paper together which gives 16" for the 16' of two sheets of plywood |
Carlson Hull program
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 |
Carlson Hull program
"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 |
Carlson Hull program
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 |
Carlson Hull program
"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 |
Carlson Hull program
"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 |
Carlson Hull program
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 |
Carlson Hull program
Card stock is a lot cheaper to buy and has the stiffness that is easy to
work with. Brian |
Carlson Hull program
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 |
Carlson Hull program
"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 $800 pricetag, just some basic math and a little common sense... I dunno, I am still not convinced, Scotty |
Carlson Hull program
Yes, ProSurf is very good, it's the old Nautilus and it handles surface
development well but it is not easier to learn than Rhino. We can all agree that whatever method you use, it will take some learning. -- Jacques http://www.bateau.com "Brian D" wrote in message news:MClBb.486707$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 |
Carlson Hull program
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 $800 pricetag, just some basic math and a little common sense... I dunno, I am still not convinced, Scotty |
Carlson Hull program
Danm, Scotty don't get that thread started again! :-)
"Backyard Renegade" wrote in message om... "Brian D" wrote in message news:Ro2Bb.270575$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 |
Carlson Hull program
C'mon ...you're making me feel bad about all that money I spent!
Brian PS: Your method guarantees fit. Can't argue with that, eh? "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 $800 pricetag, just some basic math and a little common sense... I dunno, I am still not convinced, Scotty |
Carlson Hull program
I was wondering about that. I thought that back when I did some research on
the topic, that I found that ProSurf 'was' Nautilus. Either way, it's produced by New Wave Systems ...as long as you need only the basics, it's a good package. If you want the extra stuff, like the Savitski planing hull resistance package (etc), then you pay for more 'pieces' of software to add on. I guess that's not too much different than plug-ins for Rhino, although the Rhino plug-ins tend to cost less. Hmmm...I'm betting that if a guy (gal) had to learn all three, Rhino, ProSurf, and AutoCAD, that it'd take a year or so. Add couple of weeks for a photo-realistic rendering and you've got it. By then, Scotty will have about a dozen boats built and in the water and will have spent about 1/4 of what you did ... ;( Brian "Jacques Mertens" wrote in message ... Yes, ProSurf is very good, it's the old Nautilus and it handles surface development well but it is not easier to learn than Rhino. We can all agree that whatever method you use, it will take some learning. -- Jacques http://www.bateau.com "Brian D" wrote in message news:MClBb.486707$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 |
Carlson Hull program
By then, Scotty will have about a dozen boats built and in the
water and will have spent about 1/4 of what you did ... ;( Yes, that's true but my interest is in design more than building. I did enough building . . . Nautilus from S. Hollister is now ProSurf, correct. I got it from Westlawn, it was part of one of their design courses. So, that maybe a solution for those who are interested: take the Westlawn CAD course. You'll get software at student's price and a teacher will help you learn it. Westlawn is good, probably even better now that Dave Gerr is their director. Thta's if learning design is your goal. To build one boat, I second's Scotty's method. -- Jacques http://www.bateau.com "Brian D" wrote in message news:aRABb.498122$Fm2.478352@attbi_s04... I was wondering about that. I thought that back when I did some research on the topic, that I found that ProSurf 'was' Nautilus. Either way, it's produced by New Wave Systems ...as long as you need only the basics, it's a good package. If you want the extra stuff, like the Savitski planing hull resistance package (etc), then you pay for more 'pieces' of software to add on. I guess that's not too much different than plug-ins for Rhino, although the Rhino plug-ins tend to cost less. Hmmm...I'm betting that if a guy (gal) had to learn all three, Rhino, ProSurf, and AutoCAD, that it'd take a year or so. Add couple of weeks for a photo-realistic rendering and you've got it. By then, Scotty will have about a dozen boats built and in the water and will have spent about 1/4 of what you did ... ;( Brian "Jacques Mertens" wrote in message ... 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 |
Carlson Hull program
"Brian D" wrote in message news:MClBb.486707$Fm2.472295@attbi_s04...
[snip] ...the book by S. S. Rable. I believe it's still for sale. Look for "Ship and Aircraft Fairing ^^^^^ Rabl, if you're searching for it :-) and Development." Rabl, S.S., "Ship and Aircraft Fairing and Development for Draftsman and Loftsmen and Sheet Metal Workers" reprinted 1992 by Cornell Maritime Press, ISBN:0870330969. Terrific book, but hard to find. In general, you'll get more information on development from the old aircraft lofting texts than naval architecture books, because those guys bent more metal into more shapes. Cheers, Earl |
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