Can FreeShip give me horizontal slices?

Discussion in 'Software' started by alexlebrit, Jun 5, 2007.

  1. alexlebrit
    Joined: Aug 2006
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    Location: France - Bourbriac

    alexlebrit Senior Member

    I'm thinking of glass on foam core construction, and the logical thing to do would be to cut big horizontal sheets of foam following the hull form and layer them up, then with some sanding I'll get the basic form and then I can glass.

    I've got the hull in FreeShip, but can I work out a way to get these horizontal slices out? Nope, short of shifting the waterline about and printing each one individually.

    Is there a way to do this, or perhaps a way to export to something else and do it from there (assuming the something else isn't ludicrously expensive)?
     
  2. Martijn_vE
    Joined: Apr 2005
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    Martijn_vE Marine software developer

    Export the coordinates of the waterlines to a text file and draw these manually on a piece of wood or cartboard. This is by far more accurate than puzzling small pieces of paper together. Make sure you have disabled the "simplify intersections" setting.
     
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  3. Windvang
    Joined: Jan 2006
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    Windvang Yacht Designer

    Export linesplan with all waterlines as dxf., look for free or cheap CAD program (plenty around) use dimension function in CAD program to measure width at each station.

    If you are talking about your pedal boat most plotting shops can print that out full scale (1 side of boat) for around 60 EU If you use cross sections instead that will even be less.

    You don't have to shift waterlines you can select multiple.
     
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  4. Guest625101138

    Guest625101138 Previous Member

    Alex
    I think Martijn assumes you have set the waterlines.

    You do this by <Calculation> <Intersections> select the Waterline button then the +N and set the spacing to the thickness of your foam - say 50mm.

    You then Export the Offsets.

    I have attached what I produced with the boat facing forward. So "0" is the stern.

    I think you will find cutting the foam to be tedious. Even hot wire is difficult unless you have guides.

    You could always simplify the lines to make it easy to build. Remember that water and air take less effort to move in gentle curves.

    Rick W.
     

    Attached Files:

  5. alexlebrit
    Joined: Aug 2006
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    alexlebrit Senior Member

    Thank you one and all and especially thank you Rick. I wanted to start with a 1:10 scale model, so in fact I popped all the waterlines in FreeShip, selected Plan View annd then Printed that out using the pdf995 program, which will print to a PDF file. Then I opened that up using Photoshop and spent a bit of time splitting it into two contour maps, the first of the hull form and the second of the deck/superstructure form. Printed those out and had endless fun with Spray adhesive and 4mm thick polystyrene, glue and sandpaper, and voila, I know have a 1/10 scale model.

    As FreeShip will print on a 1:1 scale, and I have tax deductable print costs I'm sorely tempted to do the same thing.
     
  6. Guest625101138

    Guest625101138 Previous Member

    Alex
    You can reduce a step in the process by using the faithful right-click mouse button when you are in plan view. This allows you to save a bitmap image that can be loaded directly into your image handling software and scaled as required.

    Would be great to have a printer that could print out big sheets. I am stuck with marking up although I can print out bulkheads for narrow hulls that save a bit of work depending on how I build.

    Rick W.
     
  7. kengrome
    Joined: Jul 2006
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    kengrome Senior Member

    I wish FreeShip could produce transverse cross-sections with the mold borders marked on a grid -- like "develop plates" but perhaps called "create cross sections" instead -- so I could easily create the molds for building the boats I'm designing.

    Any ideas of how I might do this now, or if it might become a feature in a future version?
     
  8. Guest625101138

    Guest625101138 Previous Member

    Ken
    I am not sure if I got the correct understanding of your question. I have attached an image of what I think you mean.

    Rick W.
     

    Attached Files:

  9. kengrome
    Joined: Jul 2006
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    kengrome Senior Member

    That's close Rick, but what I am actually hoping for is the coordinates of the intersections of the grid with the cross-section curves.

    With the coordinates I can build very accurate molds, but without them I have to "guess" at the coordinates where the cross section curves intersect the grid.

    The "develop plates" feature provides these coordinates of course, but only for the developed panels, not for cross sections that I would use to create my molds ... :(
     
  10. alexlebrit
    Joined: Aug 2006
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    alexlebrit Senior Member

    Rick you can indeed. The advantage to the method I described is that it allows you to scale things within the process, rather than having to scale up in an image editor - never an easy task. Also if you scale that way the thickness of your lines stays the same at 1 pixel, and the curves become curvier and less pixellated, whereas if you scale up the bitmap, you scale up the size of each pixel - if you see what I mean.

    I'd thoroughly recommend pdf995, it's free to use, and very useful for all sorts of printing operations.
     
  11. Guest625101138

    Guest625101138 Previous Member

    Ken
    You can get the text version of what I think you want using the Export to Michlet. Michlet works on a hull grid of intersecting waterlines and stations.

    It takes some thinking effort to understand the data set. You also have to pull it out of the Michlet .mlt text file. I have done this in the attached Excel file. As a check I plotted the stations on a chart shown in the file. Note that the chart is not to scale. It also shows some obvious discontinuities on the centreline (bottom axis of the chart) due to the coarseness of the waterlines. The same thing happens when you use Michlet to produce offsets that are imported into FreeShip. It pays to have waterlines close together to avoid large discontinuities.

    You can set the number of waterlines and stations when you export to Michlet. Also if you want to get the full hull you need to sink it. (Set the draft higher than the highest point). By choosing the right number of waterlines and stations during the export you can get nice even grids. I have used a 0.1m grid for the waterlines so this gives fair resolution for the size of hull shown. The Stations are at 0.4m intervals - maybe more than needed.

    Rick
     

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  12. nero
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    nero Senior Member

    Stacking foam to make a model boat may have worked well for you. Imagine the waste if you intend to do this on the full size boat.

    It would be better to reproduce your intended building method when making your model. This helps to illiminate problems that at full scale could be project ending.

    There is a technique of strip foam. It uses strips of foam like corecell to strip plank the boat. Never used it myself.
     
  13. alexlebrit
    Joined: Aug 2006
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    alexlebrit Senior Member

    Well it does of course depend on what you want to do with your model boat. If it's just to look at, have sat on your desk and wave around at visitors to bore them to death, then quite frankly who cares what it's made of, especially when it's 2 foot long.

    And in fact i'm planning on using this method for the real thing too, it's really only a kayak-a-like thing, so I won't have huge amounts of wastage - the reason for doing this, was so that I COULD replicate the build, so as my foam comes in 2m x 1m bits, I started with 20cm x 10cm pieces of paper, so see how much wastage there would be.
     
  14. bhnautika
    Joined: Feb 2006
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    bhnautika Senior Member

    Alexlebrit you seem to be confusing vector lines produced by CAD and raster used by graphic programmes. Take the lines you want out of freeship in DXF format and import them into any CAD. From there you can get any measurement you want to whatever accuracy you want.
     

  15. nero
    Joined: Aug 2003
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    nero Senior Member

    Alexlebrit
    Can you post a picture of your model? How thick are the sheets of foam?
     
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