Creating hull form from not so good lines plan

Discussion in 'Software' started by Jure29, Sep 20, 2017.

  1. Jure29
    Joined: Sep 2017
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    Jure29 Junior Member

    Hello fellow members.
    Im a some kind of newbie when it comes to rhino, but have 10 years of experience in shipbuilding industry, from workshop documentation to being in production as a mostly hull architect ( no colege degree ). Recently i returned to a design office and planning on learning the complete process of calculation and design to help my co workers.
    I have some lines plan and everytime i fair a station curve my buttock or waterline are not intersecting.
    Im only using rhino and t spline plug in ( but not very much t spline ).
    And i have seen some pretty amazing models with small amount of control point and all in one surface.
    I cant get even the midship section or a tube with that kind of amount.
    Please help
    Much appreciated
     
  2. Alexanov
    Joined: Feb 2003
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    Alexanov Senior Member

    Do you really think to make hull from one surface is a good idea? I do not use Rhino for lines fairing, but mathematics behind is same. If you need to make well faired hull you need to make flat side and flat bottom as separate surfaces.
     
  3. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    I suppose you try to reproduce the shapes of an existing helmet. My first tip is to not worry if you have to use several surfaces to define the hull. The unique surface to define the hull is almost impossible to get and, moreover, not worth it .
    Another tip is to try to define cross sections and waterlines using a 2D drawing program. Once smooth lines are obtained, use them to get the surfaces of the hull.
     
  4. Jure29
    Joined: Sep 2017
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    Jure29 Junior Member

    I have a model from a member here who has made it and it looks easy but it ain't. I know that rhino makes a mess from it when you do it. Its to stiff and its never laying on the flat curve.
    How can you make CFD it its not watertitght or you use triangulated mesh?
     
  5. Jure29
    Joined: Sep 2017
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    Jure29 Junior Member

    I never done the whole hull, i have a coleague who does the complete model and we others use a different CAD software for modeling structure, but want to master it, kind of stubborn but advices aleays welcome.
    Here is a picture of a bow im wofking now for workshop documentation, its wireframe program but you can do stuf that most CAD programs cant.
     

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  6. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    Sorry, I thought you wanted "create hull form from not so good lines plan".
     
  7. Jure29
    Joined: Sep 2017
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    Jure29 Junior Member

    I got carried away, thats the first step, then till i learn the freeform of calculations for hull shapes.
    At my previous employer we started to work on a yacht that has some lines from autodesk software so inwanna receeate the whole model in rhino, from hull to superstructure.
    Also wanna improve my skills in rhino and naval architecture cause havent got any experience or knowledge of building up from scratch.
    Wanna do it step by step.
    How much buttocks and waterlines are needed to better and fair hull form?
     
  8. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    Start with 10 waterlines and 3 butocks and, if necessary to get better definition, increase the number.
    I use AutoCAD for this job and I get very good results.
     
  9. Jure29
    Joined: Sep 2017
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    Jure29 Junior Member

    I tried rebuilding curves in autocad, but always when i get them to rhino the curvature graph shows not smooth transition in radiuses of curves.
     
  10. Jure29
    Joined: Sep 2017
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    Jure29 Junior Member

    Maybe im doing something wrong.
    As i know in rhino there are b-splines but in multisurf a c-splines like in software im using for building drawings.
    C-splines mora accurate?
     
  11. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    Splines, any type, are difficult to handle in Rhino because you should work with fit points, rather than with control points.
    I try to get smooth surfaces in AutoCAD and then export them to another CAD program, if necessary. Maybe you should use, not another type of spline, but another way to define your surfaces. Depending on the hull you are defining, it may be easier to define the surfaces by cross sections or by water lines.
    Show me the file you're working on and I'll see if I can clarify anything.
     
  12. Jure29
    Joined: Sep 2017
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    Jure29 Junior Member

    Im currently working on a container ship but still gonna try fairring station lines, then go for other curves but in autocad first like you said.
    Do you prefer orca plug in it seems to me that its the only way to make a fair surface of whole hull or freeform.
    I also downloaded allot of video tutorials so gonna watch them.
    Thanks for the tips and advices.
    Good speed
     
  13. rwatson
    Joined: Aug 2007
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    rwatson Senior Member

    You might like to check out some tutorials in YouTube

    eg

     
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  14. Jure29
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    Jure29 Junior Member

    Thanks will do, is there any other marine tutorials except that rapid hull modelling on rhino site?
     

  15. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    PS. Also, Lookup the Crv2View command in the tutorials. You can convert Plan and Elevation lines to the Sheerline or Chine
     
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