2d pattern to 3d hull

Discussion in 'Software' started by Alball, Sep 7, 2014.

  1. Alball
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    Alball Junior Member

    I would like to model a stitch and glue design in cad before I build and I am looking for software that can join the 2d plywood hull patterns into a 3d hull. Does such software exist? The closest I have seen are some fabric manipulation programs but hey are very complicated and expensive.

    I use rhino and Solidworks regularly, but if have not found an easy way to do this in either program.

    Best,

    Al
     
  2. TANSL
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    TANSL Senior Member

    You can do it with Rhino, placing the cross sections in the correct position in space and using the various commands that Rhino has to create surfaces that are supported by multiple lines.
     
  3. Alball
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    Alball Junior Member

    Ah, yes, TANSL, that would be easy if I had the cross sections, which I do not. I just have the developed 2d pattern shapes which get stitched into a hull shape.

    Another way to think of it: recreate the shape of a five sided banana in 3D from the 5 2d shapes of the peel.
     
  4. TANSL
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    TANSL Senior Member

    Sorry, I had misunderstood.
    If 2d patterns have drawn lines of the frames, you can try with any cad program.
    Can you show me what you got?
     
  5. DCockey
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    DCockey Senior Member

    Al, did you ask the same question in the Rhino3D forum several days ago, or are there two different people on the same quest?

    One suggestion is to start with a physical model. Print the panel shapes on stiff paper and tape them together to form the 3D shape. Measure that shape to create an initial set of offsets.

    Then use the initial offsets in Rhino to create a 3D model. Adjust the model as required so that the panels are developable. Extend the edges of the panels in the 3D model past each other. Put curves on the panels where the original edges were. Unroll the extended panels. Next fit the original panel shapes onto the unrolled extended panels. There is a method in Rhino to go from curves on an unrolled panel to curves on the 3D model which has been described on the Rhino forum. Use that to put the original panel edges on the 3D model.

    Next revise the 3D model to make it closer to the original panel shapes, and repeat the process in the previous paragraph. Iterate until the agreement is satisfactory.
     
  6. PAR
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    PAR Yacht Designer/Builder

    Alball, welcome to the forum.

    It might be easier to simply state what you're trying to do. To me, it sound like to have a set of plans with no lines or offsets, but just "developed" panel dimensions, that you cut to and use to assemble the boat. The reason most designers do this (don't offer lines drawings) is, to prevent you from stealing the lines of the boat, mostly because with the new, low cost and free software packages now available, make hijacking a design quite simple, in spite of any copyright protection. So, what are you trying to do?
     
  7. Alball
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    Alball Junior Member

    TANSL, I am trying to figure out an easy way to do this:
    [​IMG]
    on the computer so I can model variations of the next boat I am going to build.:confused:

    Dcockey, that was either me or my dog on the Rhino forum.;) I know I can make a physical model, but my challenge here is to do it in CAD. It seems like it should be simple but I am finding that it is not. If I can figure it out then I can easily print models on my 3d printer, or cut them on the cnc mill.

    I may end up iterating as you suggest by cutting the panels into smaller pieces and fitting them on the center-line and sheer line. I was just hoping to find a rhino or solidworks command, plugin, or other software that would automate this process.

    PAR, thanks for the welcome. I thought my original post was pretty straightforward, but maybe this post makes it clearer. I have many sets of stitch and glue plans, some I purchased (these give me the right to build one boat of the design), some are from books I have purchased, and some I created cutting thick paper and forming into hulls with scotch tape. It is my intent to model some hulls in 3D CAD, play with the sheer lines, cabin designs and configs, internal infrastructure and furniture, etc., to create a design to build.

    Do you think that this is unreasonable? Do you mean to suggest that I am trying to steal a design?:eek: If so that does not make sense because I'm starting with hull panel patterns which I own the rights to.

    I am still interested to know if there are any software tools available that can virtually stitch 2d patterns into 3d shapes.:?:

    best,

    al
     
  8. PAR
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    PAR Yacht Designer/Builder

    To specifically answer your questions, yes, there are software packages that will generate developed panel shapes from 3D models, but you're asking to do the reverse, which is the hard way around the bush.

    Simply put, there are free and nearly free packages that will permit you to draw a set of shapes that can be "unfolded" into the flat panels you's like to work with. Unfortunately, these programs will not tell you how well suited a set of 3D shapes are, for the intended uses of the boat, nor offer the appropriate scantlings information for it's structure.

    Bluntly, the software will faithfully regurgitate the shapes you've inputted, without regard for suitability structurally or in use. So, if you go in blind or attempting to reverse engineer something, without a reasonable command of the engineering, physics and hydrodynamics involved, the software will happily provide lines for a crappy boat.

    This said, if you have some building experience, some things can be reasonably assumed (to a degree), such as planking thicknesses, framing elements and other structural considerations, in normally shaped and casually used boats. This means you have enough intuition to make reasonable guesses, unless you're trying to go really fast or attempt to stretch the design envelop past normal parameters, where you'll need to understand the additional considerations often applied in high speed or highly stressed craft. So, if you're just looking to develop some shapes and their developed panels, for say a self designed 16' center console, that's not going to be asked to blast along at 60 MPH with 250 hanging on it's butt, then sure, you can get fairly good results, with one of several programs. If on the other hand, you'd like an impressively quick, well balanced, safe and reliable vessel, there's a whole lot more to it then a software package.

    Lastly, yes it seems like it should be a simple set of tasks, but to the computer, it's not and then there's the hydro stuff that creeps in to makes things more confusing. Couple this with prerequisite engineering standards and other considerations, a bundle of stuff you may not want to know. You'd be best advised to get the Geer book "Elements of Boat Strength" to place you in the ballpark on structures and other design considerations. There's lots of books you can absorb, to get the understanding necessary, but for small, simple boats, you'll be well armed after sucking through "Elements".
     
  9. Alball
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    Alball Junior Member

    yup, I hear everything you are saying but my ambitions are not so grand. I just want to document an existing design on the tube so I can design the interior details. I not looking to re-design the hull, just document it so I can work inside it.

    I have often unrolled developable surfaces in Rhino for work. I just wondered if there was a way to do it backwards. From what I hear, and my research online, I am finding that it is not so easy to go from 2d patterns to a 3d hull shape this way.

    thanks for your insights.

    best,

    al
     
  10. SukiSolo
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    SukiSolo Senior Member

    I don't know if there is an easy way to do this. However you do have a 2D pattern so a lot of information. No reason why Rhino could not re engineer this perfectly well.

    The two most useful starting points are the stem line and the transom. If the transom is vertical, even better. This allows you to take the 2D 'line' from the flat drg and place it in one elevation, say side. The stem you can assume to be on the CL, whereas the transom can assumed to be symmetrical. Then with careful placement of points and subsequent Deg 3 splines, the line lengths can be arrived at accurately ie chines. By tweaking between developing the 'new' surfaces and the pattern ones a very good match could be made in reasonable time. You will become very familiar with curve editing commands and distances (lengths).
     
  11. TANSL
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    TANSL Senior Member

    As far as I know, that software does not exist.
    If you have some more information, such as the longitudinal profile, it is possible that, for example with AutoCAD (or several other CAD programs), you could define a very good 3D model of your boat, but always working in a "manual" way.
     
  12. rwatson
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    rwatson Senior Member


    I am playing with that now in Rhino.

    have you checked out Oreint3Pt yet ?

    Can you tell me first, where did you get the file with the flat panels from ?
     
  13. TANSL
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    TANSL Senior Member

    rwatson, as you know, I really like these themes. Therefore, if you get any progress, I would like you to share your experiences.
    I think there is no way to correctly locate any line in space, no valid references, so it is not possible to do a proper job. You should begin a process of trial and error, very laborious, with little chance of success.
    I look forward to your comments.
     
  14. rwatson
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    rwatson Senior Member

    Yes, its fun.

    That's why I asked where he got the flat sections from.

    It would be a nightmare to try to resolve them by eye, but if he also got a few vertical stations as part of plans etc, it might be feasible.

    I have been practicing with control point manipulation from the Youtube video I posted a few days ago, and this has opened up a whole new way of doing business

    hgjxO5yuRxg
     

  15. TANSL
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    TANSL Senior Member

    Yes, as the forms are simple, one vertical, cross section or longitufinal section, probably, would be enough.
     
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