Manual or CAD

Few would argue that CAD is the future of marine design; some would say that manual drafting is the past; but what is the present....?
What do you use ? Why ? When ?

 

I've voted for Amateur designer / Student - Manual + CAD

I'd say CAD is over 90%, but, if I have an idea it might be faster just to draw it by hand. Also, doing the GAs, I find it easier to plot the basics (hull with its divisions) and draw some by hand. Then I'll scan it and start properly with CAD.

Also, I usually plot the drawings and correct them by hand; but I don't think that counts as drawing by hand, does it?

 

definately amature

I voted for " Amature With CAD/HAND"
I myself like to laydown her preliminary with Ye Olde Pencil. I can feel the design out better on paper throw in a little shading to see
if she is worth spending more time on. After I like the basic idea
I will scan her in and lay down the vector lines. I can then use the accurate cad dimensions for math. I do not have a marine drafting program as of yet. I like the Vacanti 98 It seems to be fast to learn. Anyway thats the method to my little madness!
8Kts

 

I'm a student 1/2 way between the manual nad manual + CAD camps.
I'm struggling to find a software package that I'm comfortable using (and can afford...), so at the moment I lie towards the manual end of the spectrum. But once I get the hang of all this computer stuff I reckon I'll end up like '8' - doing most of the preliminary stuff by hand then finishing it off with CAD

 

Professional - I do the preliminary designs by hand as it is easier for me to sketch and think with a pencil. I then transfer the drawings to CAD for the actual finished drawings as CAD is easier for detailing. I will admit to also continuing with 2D, even though I have a 3D CAD program. The added complexity of drawing in 3D is not worth the effort, especially when I still have to convert everything back to 2D in order to create the working drawings. I use 3D when I need a different perspective on how something will look and want to rotate it around and look at it.

 

Timm if you still think 3D is Harder than 2D and that you still must convert back to 2D ofr shop dwgs then your not using the right program. Try someting like Inventor or solidworks I sear you'l never want to work in 2D again. Price to high just to try, then check out the PTC web site you can get a free version of ProDesktop, almost as good as inventor and it's FREE. this is a fully functional program I think it is only lacking the ability to do 2D dwgs but if you like it the full version is not priced out of sight
Like some of the other folks here I still like to hand draw the pre skecths, seems its easier to get a good look of the lines on paper ver the screen.

 

Converting back to 2D isn't a problem with Ashlar-Vellum Graphite, it's actually a single command. Graphite is a wireframe program, not a solid modeler. This means that all the points of the hull have to be faired in 3D space. I find it easier to do this in 2D. Ashlar makes a very good upper end program that does surfaces and solids, but for many things that is overkill, especially the $2,000 upgrade cost. When you are drawing cabinets and plumbing systems for the relatively small boats that I work on, there really isn't a lot of use for solids. It may be because I designed by hand for over 10 years before getting into CAD, but I have never bought into the line that you couldn't design accurately until CAD was invented. I worked to a sixteenth of an inch with relative ease by hand, which was more than accurate enough considering the abilities of the people building the boats. If I put a 1/32 measurement on a drawing they would have laughed at me!

I'll probably upgrade to a solids program eventually, but I'll need to design a lot more boats to write the check! By the way, I don't quite understand how Solidworks or Inventor can create shop drawings without going to 2D. I am talking about traditional 3 view detail drawings covered with dimensions and notes. They may be able to show all three views, but how would you dimension if it didn't "flatten" the view in some way? I would think you would have a problem with dimensioning lines at another level and actually having dimensions that looked right in 2D, but were wrong when viewed in 3D (I hope that makes sense!). Just curious.

 

Amateur using CAD only

Just a short tale of things I’ve learned and mistakes I’ve made, while using CAD software to draw boats. I have been building a digital 3D model of a canoe I built a few years back. My goal is to use this hull form as a starting point for a different boat. While discussing this idea with the original designer, I agreed to supply him with a set of lines from my model. The plans are one sheet with the shape of the stem, stern, and half stations. I recorded XY points from these lines and entered them into Rhino. The model I created from the points looked very much like the canoe I own, so I was very pleased with myself. I had to make a few minor deviations during the fairing process. At this point the whole process had gone by the book, so I assumed my lines were correct and the original lines were wrong. After all, he used pencil and paper and I had a computer. When shown my lines the designer was polite but not happy. So I agreed to play with it some more. After much tinkering I was able to come up with lines very close to his. I started to learn a great deal about the editing tools in Rhino. Also how a minor change in one spot will affect many other spots. With everyone happy I agree to do another hull. This one required no editing and was virtually identical to the original. My lines are to be used as the new plans and will have my name on each sheet. Now I have no reputation in this business so I was a little concerned that all was correct. It bothered me that one hull needed so much editing and the other one, none at all. After doing many checks, I went back and checked some basics. I found that the model of this 192” boat was only 183”. I had made a very bad mistake right in the beginning and it ruined everything from that point forward. With the error corrected the lines came out the same as the original.

I have offered my apologies to the designer for my insult. I have discovered for myself that CAD isn’t better than paper, just different. And I have learned how to use many of the editing tools in Rhino. Now the professionals here can lean back and nod with a smile. But I hope by sharing this, it might be of some small help to those that are starting out.

Gary

 

Gary, you aren't the first, nor the last to do something like that. On the screen it is very hard to get a feel for scale without actually measuring something. On paper I could tell when something was off just by look and feel. I especially get nervous when making major changes - did I get all the changes in all the drawings? Sometimes I check myself 3-4 times before I feel comfortable. I sometimes miss being in an office where someone else went over all my drawings before they went out the door!

 

I think that for many calculations like: panel loading, displacement, stress points, etc. a computer is a wonderful thing. However, new designers that never used battens and pigs, learn to draw lines restricted by a program designer. The programs are usually written by a computer expert with no experience on boats. Also it is not possible, in a computer screen, to eyeball the lines; it is too small. I have lofted many boats, and a pencil line becomes 3/4 of an inch when scaled full size on a 60 foot boat. A pixel is probably a couple of inches. The result is clear in the barrage of ugly boats. Few still learn that tweeking a line frctions of an inch in thirty or forty feet make a hughe difference. All the science is much easier in the computer, but the beauty is easier with a pencil.

 

hmmm

I agree... sort of...

beauty is often easier with a pencil.

But saying that he hull programs are "usually written by a computer expert with no experience on boats" is plain wrong and very unfair to the guys that all started the different hull design software.
I think every current hull design program came out of a frustrated yacht designer rather than a programmer, sure a yacht designer with a great feeling for math and an interest in programming, but none the less a yacht designer. ebviously the larger companies employ "normal programmers" (if they exist, I've never met one)

And you can also have your design written out as a linesplan on a largecale printer with good resolution, that makes another way to "eyeball" the lines.

Just my 0.02 €

 

“normal programmers” LOL!!! They don’t exist, that’s my job title some days, and I’m not normal. (not a geek either) I agree 3D can be a pain, but once you have a model, you have all you need. If done right the full size lines can be as fair and as pleasing as ones drawn by hand. A digital 3D model is a lot of work but when complete it is amazing the amount of information you can get from one. Plus you can send that info. around the world without losing any data. Someone in Turkey has access to the same data I do. I’m staring at my drawing board as I type this.

Gary

 

I guess I got a bit carried away. However, the programmer gives the designer a limited set of options. The freedom of wooden battens is something I haven't found in any program yet. Another advantage of battens is that if they bend through some points, a plank will also. Of course this is irrelevant with FRP. The cost is another concern also. I agree that if you have the capability and budget to print full size, change lines and keep in printing, eyeballing lines is possible. My setup, wooden battens, lead pigs, squares, pencils, etc. is more economic. It is more intuitive for me to tweek a batten, finish a design and enter the table of offsets for calculations. My strongest complain is that CAD systems prevent designers from experimenting outside the program parameters. Both systems have good qualities and together are excellent. Sorry ir I offended anyone. And no one can accuse me of calling a programer "normal".

 

LOL!! No one was offended. And you have made some good points that I agree with. My humor isn't easy type out.

Gary