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#21
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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 $800 pricetag, just some basic math and a little common sense... I dunno, I am still not convinced, Scotty |
#22
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Carlson Hull program
I was wondering about that. I thought that back when I did some research on
the topic, that I found that ProSurf 'was' Nautilus. Either way, it's produced by New Wave Systems ...as long as you need only the basics, it's a good package. If you want the extra stuff, like the Savitski planing hull resistance package (etc), then you pay for more 'pieces' of software to add on. I guess that's not too much different than plug-ins for Rhino, although the Rhino plug-ins tend to cost less. Hmmm...I'm betting that if a guy (gal) had to learn all three, Rhino, ProSurf, and AutoCAD, that it'd take a year or so. Add couple of weeks for a photo-realistic rendering and you've got it. By then, Scotty will have about a dozen boats built and in the water and will have spent about 1/4 of what you did ... ;( Brian "Jacques Mertens" wrote in message ... Yes, ProSurf is very good, it's the old Nautilus and it handles surface development well but it is not easier to learn than Rhino. We can all agree that whatever method you use, it will take some learning. -- Jacques http://www.bateau.com "Brian D" wrote in message news:MClBb.486707$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 |
#23
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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 |
#24
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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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