Ruling lines in Delftship-Freeship

Discussion in 'Software' started by Newhill, Feb 7, 2014.

  1. Newhill
    Joined: Sep 2012
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    Newhill Junior Member

    Correct me if i'm wrong... The vertical edges between faces, along a developable hull side, or transversal edges along the bottom are in fact ruling lines?
     
  2. DCockey
    Joined: Oct 2009
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    DCockey Senior Member

    Not sure what you mean by some of your terms. An illustration, even a simple sketch would help.

    Developable surfaces can have ruling lines at any angle to the edges of the surface. For hull sides the ruling lines will usually not coincide with frames unless the angles of where the frames intersect the hull side are the same.
     
  3. The Loftsman
    Joined: Jun 2010
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    The Loftsman The Loftsman

    Ruling Lines

    I would tend to go with the other poster (David) and a picture or sketch is worth a thousand words, ruling lines on the developable surface (used for rolling of the plate etc) will not run parallel unless the plate happened to be completely square with the frames then it would be a part cylinder.



     
    Last edited: Feb 7, 2014
  4. Newhill
    Joined: Sep 2012
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    Newhill Junior Member

    Here is a picture from Delftship. I did some fiddling with the controlpoints, and now i se that the vertical lines between points on sheer and chine can't be ruling lines.
    Isn't there some way to show ruling lines in this application?
     

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  5. The Loftsman
    Joined: Jun 2010
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    The Loftsman The Loftsman

    Ruling Lines

    Don't know about Delftship,
    Newhill


     
  6. philSweet
    Joined: May 2008
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    philSweet Senior Member

    No. At least not in the ancient version I have. It's better to go back to Rabl's method on paper for that, unless somebody has implemented Rabl's method in a spread sheet. Designing developed surfaces from scratch is full of grief in FreeShip. I work them up on paper, then transfer to FreeShip, and patch in any curvy bits. Using any kind of intersection command tends to ruin the result. Also, the developability checks are dependent on the grid and on the scale being used. Ie. low, med, high, highest produce different results. There are definitely right and wrong ways to lay out a mesh for a developable surface in FreeShip. It takes some practice, and an understanding of how the surface is calculated certainly helps. Where possible, keep crease control points on a ruling line and let the stations take care of themselves. This presumes that you start out knowing the ruling line geometry and that you can use control curves and the curvature function to full advantage.
     

  7. lewisboats
    Joined: Oct 2002
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    lewisboats Obsessed Member

    You can use stations, waterlines and buttocks to create a 3D grid on the model.
     
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