Cat’s and Tri’s

DELFTship forum Hull modeling Cat’s and Tri’s

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    • #36054
      David Smith

      How do I do Multihull’s in FREEship?

    • #36057

      This is my way, but it’s possibly not the better 😛

      1. I draw the half of a side-hull (port or starboard).

      2. I ask FS to actually draw the other half (not just to show the symetry). This gives me the two side-hulls, but I can see only one: they’re both drawn on the same place (overlaping?).

      3. I move the side-hull off the symetry plane. Thus I get my two side-hulls with a gap between.

      4. I draw the arm(s) connecting the side-hull to the symetry plane, by extruding a part of the side-hull’s inner board.

      The Cataman (twin-hull ship) is done.

      5. For a trimaran (three-hull ship), I draw shorter arm(s) then I draw the central hull by extruding the arm(s)’s edge frontward, backward and downward..

      The Trimaran is done.

      – Draw your ship’s differents parts on differents layers. This will help with sophisticated drawings and use different colors.
      – There are two tools concerning the symetry. One just shows the other half of your ship, the other one actually draws it, knit it to the first half and make both halves an only object.
      – It’s easier to draw the multi-hull ships from the external board toward the symetry plane.

      You can draw non-symetrical ships, too!

      I hope this is clear enough since english isn’t my mother tongue. :unsure:

    • #36058
      David Smith

      Thanks, uh how do you move things off the symetry plane

    • #36081

      Well! I’m back after downloading and installing the last version. (Wow! It’s pretty different of the old FS 2.6 I was using. ThanX to the Delft Development Team! :woohoo: ).

      I quickly drew an example for you, taking screenshots from times to times. Here you have the result. Watch a picture, read it’s title, find the result on the next picture. It’s not as easy to draw as to watch the pictures, but if you already understand how to extrude polygons and how to knit them, you’ll succeed.

      Concerning the FreeShip new design, you have to understand how the tools are gathered:

      The layers, points, edges, polygons and display operations are gathered under the HOME tab.
      The meshes operations are gathered under the TOOLS tab (move, rotate, scale, mirror).

      So when you wish to MOVE a whole mesh (or many at once), deselect all, click on MOVE (TOOLS tab), select the mesh(es) to be moved, fill the relative coordinates and click on OK.

      You can move just a point or an edge (or many edges) by selecting them, and clicking on MOVE.

      Remember: Positive coordinates are orientated forward (longitudinal axis), outward (transverse axis) and upward (vertical axis) according to the box you’re filling.

      Remember, too, a few of hydrostatics data are inconsistant with the multi-hull designs: lateral area for example. I assume it’s based on the wetted part along the symetry axis… which doesn’t exists on a catamaran and is not significant on a trimaran (above all with a ship such the one I drew!).

    • #36082

      And here you have the example’s file itself:

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