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Thread: CAD type programs

  1. #1
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    Default CAD type programs

    I am looking at a thread on the modelshipworld site about a guy who's building a digital model of the Ernestina in Blender 2.79. He did one in Fusion 360 as well.

    Hull modeling with Blender - CAD and 3D Modelling/Drafting Plans with Software - Model Ship World™

    My question is this: what benefits does Blender have over something like Delftship, sketchup or another CAD program? Can Blender do the things that one would need to do if they were trying to digitize a set of plans and be able to manipulate them, adjust and add detail etc. as one would try to do prior to building a full sized vessel? What program (preferably a free one but if not, a not too expensive one) would I best be advised to use for that purpose?
    Thanks,
    Daniel
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

  2. #2
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    Default Re: CAD type programs

    Blender is a wonderful app! However, in spite of recent advances (plug-ins) that aid in CAD type measurement and layout, it is not really the best solution for naval architecture. Blender is not written to accommodate necessary calculations or projections. You can certainly design a boat shaped object with Blender. I've actually done it by accident. Blender, however, will not serve well to produce a set of plans.

    Where Blender really earns it's salary is taking your 3d model and making it look pretty, putting it into a realistic scene, and animating it. If you want to make a move starring your as yet un-built yacht, Blender is the ticket. But for designing your beauty, you'll be much better served by more specific design packages such as Delftship.

    P.S. I must honestly temper my comment with the fact that I have much experience with Blender, but little with Rhino or Delftship, or ...

    I love Fusion 360, but I won't be buying the paid version. I want to be able to use my software without a connection to the Net.
    Schooner sailors love to get blown offshore!

  3. #3
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    Default Re: CAD type programs

    Does Delftship do things like model weight as well or is it more simple than that? I'm thinking Delftship is what I need but want to be sure. I don't mind coughing up some $ to get the right program for me needs as long as it's not stupid expensive, but I want to make sure I'm getting the right program for my needs. Designing the beauty as you put it is what I'm looking to do. Sort of. I purchased the plans from the designer, I just want to digitize them so I can "explode" things, pull out individual station moulds. Essentially, I want to loft her out in some CAD program so I can do make changes to say, details of the deck framing, or figure out how much space there really is in the aft lazarette locker/cable locker etc.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

  4. #4
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    Default Re: CAD type programs

    I produced a design in Freeship. I exported the plank expansions and lines plan, then imported them into Draftsight to create the internal structure and nest the components.

    The finished GA
    6 strake coble_Linesplan.jpg

    The nested planks and stern
    6 strake developments.jpg

    The working GA
    6 strake coble GA.jpg
    It really is quite difficult to build an ugly wooden boat.

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  5. #5
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    Default Re: CAD type programs

    Does freeship do developable surfaces too or just hard chine, flat panels? The design I have is carvel planked, not ply etc.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

  6. #6
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    Default Re: CAD type programs

    Quote Originally Posted by Sailor View Post
    Does freeship do developable surfaces too or just hard chine, flat panels? The design I have is carvel planked, not ply etc.
    Only if you are verry lucky in your design. It can show you where the surface is developable, but with carvel it is not necessary. You just hang narrower planks and fair off the ridges with a plane and or long board.

    P.S. flat ply planks are developed surfaces when hung on the boat, so yes that is what Freeship does for multi chine and broad strake clinker like my 6 strake coble.
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
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  7. #7
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    Default Re: CAD type programs

    Do you remember me using the line, "for every boatbuilding problem there are at least a dozen solutions, and two or three of them are correct"? Well, it's the same thing with CAD software....

    I think that a lot depends on a.) how good you are at using 3D modelling and 2D drafting software, and b.) what you are trying to accomplish. If you want to create a hull and then stretch an pull and squeeze it into a new shape, then 3D modelling with programs like Rhino are just the thing, except they are not great at pulling out 2D plans for building and don't tell you anything useful like displacement and centre of buoyancy. If you want to create building plans, it is not all that hard to manipulate lines plans for bigger, smaller, skinnier, deeper, in 2D drafting programs like AutoCAD if you know what you are doing, but visualization of the whole in 3D is difficult and how to do certain things - like making a fair compound curve - is not obvious. Both of the foregoing don't do carp about naval architectural calculations such as stability and displacement, but you can get add-ons for this (at a price). Delftship seems to have most of the bells and whistles that you would need, but I am unfamiliar with the program so don't know where the pitfalls are. I have never met a 3D modelling program that is easy to use to create an accurate model of an existing hull form; free-form start-from-scratch is easy, but making an accurate model of Bluenose II's hull is a challenge.

    In my old Luddite experience, there is no single cover-all-the-bases software available for ship designing at a reasonable cost. AutoShip comes pretty close, but it costs around $30,000. My suggestion would be to acquire two programs - a 3D modelling program and a 2D drafting one. Scan the lines plan you want as a PDF and import the image(s) into the 2D drafting program. Trace the lines of the PDF in 3 views. Import the 2D graphics into the 3D program and build the model around it. Squeeze and stretch the model to the desired shape. Run the stability and hydrostatics to confirm the hull. Define cutting planes to create the new lines on the model, then export the 3 orthographic views back into your 2D program to create the new lines plan. Build your new boat structure, outfit, etc. in 2D so you can extract builder's plans from it. As you add to the 2D plans, add the items and details to the 3D model to create the 'pretty picture' model, which you can then export to your Photoshop-type program to add background, texture, colour, etc.

    Carefully define what you want to create - not what boat, but what computer output (technical drawings, pretty pictures, CNC toolpaths, etc.) - and evaluate software on whether it can accomplish those ends. Be wary; there is an awful lot of bulls**t and bravado about design software. People will tell you that it can easily recreate the Mona Lisa, but when you start using it you realize that it is not much more sophisticated than Donkey Kong.

    But that's just me. the subject is so broad, the software availability so numerous (not all is what is needed, but somebody will think it's the cat's azz), and the opinions held so fiercely, that someone will be along shortly to dismiss all that I have said and opine that the software that they are familiar with is definitely the best and that you NEED to have it.

    Good luck.
    Hope for the best, but plan for the worst.

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