Rhino: make a curved bow on a developable plank

Discussion in 'Software' started by Renaud Chile, Jul 2, 2019.

  1. Renaud Chile
    Joined: Jun 2013
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    Renaud Chile Junior Member

    Hello, thanks to you, I managed to realize a plane of canoe with a bow with a curved bow ...
    I cut the planks and I started to build it.
    upload_2019-7-27_20-47-53.png

    upload_2019-7-27_20-49-41.png
    upload_2019-7-27_20-51-38.png
     

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  2. Renaud Chile
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    Renaud Chile Junior Member

    But in parallel, I am thinking about a kayak plan for my son. To train, I start by trying to reproduce plywood designs found on the internet.
    upload_2019-7-27_21-49-4.png
    What annoys me is that I block again on the bottom plank with curved bow :(. I use the very good method of Bhnautika but Rhino does not manage to unfold the plank. Maybe the plank is very wide and really not developable. I tried in different ways, positioning different section curves when scanning on two rails ...
    But that never works, Rhino never manages to unfold the plank ... If someone (Bhnautika?) Has an idea ... Attached is the Rhino file. Thank you in advance, :)
    Renaud
     

    Attached Files:

    Last edited: Jul 28, 2019
  3. jehardiman
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    jehardiman Senior Member

    With that much hollow in the entrance, you will have to do a true conic development. See Lindsay Lord's "Naval Architecture of Planing Hulls", it has the development process. There were also some other breakouts in 1940-1950 tech pubs that detailed the method. I'd have to go digging for them.
     
  4. bhnautika
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    bhnautika Senior Member

    Renaud Chile congratulations on your progress. What version of rhino are you now using ? I made a few small changes to your file and got it to un-roll. I removed one control point from the keel /stem line at the stern and added a small straight line at both bow and stern, put in some random sections, all were two point straight lines. I will put the file up when I know which version is required. RenadKayakBH2.jpg
     
  5. Renaud Chile
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    Renaud Chile Junior Member

    Waoooh Bhnautika, it seems easy for you! :) I still have Rhino version 3 (I'm waiting a bit to buy the latest version). You managed to unroll the deck's planks without any modifications?
     
  6. bhnautika
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    bhnautika Senior Member

    Renaud Chile here is the file un-modified with the bottom and top sides un-rolled in rhino 4 and 5. See if you can un-roll them in rhino 3, I also have the modified version which you can try if it doesn’t work.
     

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  7. Renaud Chile
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    Renaud Chile Junior Member

    Thanks, could you send me the edit file to see if the problem comes from my version of Rhino? With the old file, I get nothing:confused:. When I use the "unroll a surface" command, it then asks me for a curve on the surface. I do not know if I have to select a particular curve.
     
  8. bhnautika
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    bhnautika Senior Member

    Renaud Chile when the un-roll command asks the line question it only wants to know if you have any lines drawn on the surface (like station lines for frames) so it can un-roll them on to the new surface, if you don’t have any then just press enter. In the modified file posted I removed a control point (see pic) then adjusted the line to bring it back to approximately the original shape at the stern. I turned on the “curvature graph”(see pic), I not sure if you wanted a hollow in the stern but I took it out for my model. I then put in some straight sections from bow stem to stern,then “sweep two rails”.

    keel line change.jpg
     

    Attached Files:

    Renaud Chile likes this.
  9. Renaud Chile
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    Renaud Chile Junior Member

    Thanks again for your help! :) I can expand the surfaces of this new file. So this is not a problem of software version. The key would be in perfect smoothing curves :cool:. I will continue to train.
    For the bridge :(, did you make any changes?
     
  10. bhnautika
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    bhnautika Senior Member

    Yes I did make some changes to test so disregard the deck and plates but I did use the original sheer line so your deck should drop right on to the hull.
     

  11. Renaud Chile
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    Renaud Chile Junior Member

    Okay. I noticed that the degree of surfaces was different (V = 1). Changes on surfaces do not matter; this kayak is just a case study for now. I would like to draw another more personalized afterwards. I only "copied" this kayak (from 2 views).

    Well, I stop writing and I'm going to work on Rhino! See you soon.
     
    Last edited: Aug 2, 2019
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