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#1
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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 $800 pricetag, just some basic math and a little common sense... I dunno, I am still not convinced, Scotty |
#2
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Carlson Hull program
Good point: if you plan to build only one boat, it is not worth spending all
that time learning CAD. Trial and error is, in that case, a better method. You can start with a cardboard scaled model and fine tune the panels full size with cheap plywood. -- Jacques http://www.bateau.com "Backyard Renegade" wrote in message om... "Brian D" wrote in message news:MClBb.486707$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 $800 pricetag, just some basic math and a little common sense... I dunno, I am still not convinced, Scotty |
#3
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Carlson Hull program
C'mon ...you're making me feel bad about all that money I spent!
Brian PS: Your method guarantees fit. Can't argue with that, eh? "Backyard Renegade" wrote in message om... "Brian D" wrote in message news:MClBb.486707$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 |
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