Hull Modelling with stations only

DELFTship forum Hull modeling Hull Modelling with stations only

Viewing 16 reply threads
  • Author
    Posts
    • #39455
      AvatarAxel
      Participant

      Hi,
      is it possible to model a hull without buttocks and waterlines just with transversal sections in Delftship? For example there is only a bodyplan that contains no lines, just the front and aft view. Would that be possible? I am used to NURBS software but this tool is hard :dry:

      Thanks,
      Axel

    • #39456
      Avatariosif gross
      Participant

      If you open DelftShip you have “Load”, “Import”, you will see the options you have.
      See if one of them is what you need

      Best wishes
      Iosif

    • #39457
      AvatarAxel
      Participant

      Thanks! What I mean is, I use a bodyplan with transversals only as a background image. Would that be possible to build a hull from that only? I saw tutorials which all have full linesplan with buttocks and waterlines as well as the transversal bodylines.

    • #39458
      AvatarRobert Holme
      Participant

      Yes provided you know the stations, (transversals), locations along the keel line and vertically up from the baseline.

      HTH
      Regards Maryak

    • #39459
      AvatarIcare
      Participant

      Hi, Axel!

      Drawing a ship just using the stations and knowing the total length is just what I did yesterday. :woohoo:

      First I started a project for the first sketch, asking Delftship to draw just a rectangle (same length than the ship), I changed its angles’ coordinates to superimose it on the vertical plane of symmetry.
      Then I imported the picture as a background image and centered it according to the plane if symmetry (shown by my rectangle).
      I positioned the top of the rectangle at the ship’s half beam distance.
      I determined the stations intervals (comparing their number and the total length), then I divided the rectangle in as many parts as there are stations.
      I moved the superior angles back to the symmetry plane.
      I moved the mesh angles to their position to determine the edges final position.
      The draft was done. Top view and side view were loooking well.

      Then I divided horizontaly into four the rectangles, which followed more or less the diagonal slicing.

      And now, the most boring: I moved each point, one after other, until I got the model’s stations superimposed to the background image. The problem was that when moving a point you don’t change only the corresponding station profile but the surrounding stations’ profiles too.

      Neither the keel or the rudder were shown on the background image, so I had to guess. :whistle:

      Does it sound clear? :unsure:

    • #39460
      AvatarRobert Holme
      Participant

      Sounds good to me with one proviso…………………..Stations are not always evenly spaced longtitudinally, i.e. the number of frames between station x and station y may not be the same as the number of frames between station a and station b.

      It is usual to have more stations at the extremities, (bow and stern), where hull shape changes are more pronounced than midships where hull shape between frames is very similar, if not the same with high block coefficients.

      HTH Maryak

    • #39461
      AvatarAxel
      Participant

      Hi Icare,

      thanks for your explanation or brief tutorial how you did. It does not sound completely clear, but not weird at all 😆
      So I will try to get it same way..

      Cheers,

      Axel

    • #39462
      AvatarAxel
      Participant

      Commonly, if you have a bodyplan with the transversal section from a shipyard, it is divided always in the same distance based on the LPP. As you said, fore and aft part is rather complicated designed hence they sub-divide the stations by half, but always the exact distance.
      If you have a final framing plan where all frames are shown (can be 200 or more depending on the vessel’s length) then you have to stick with the frame distances shown on each general arrangement plan.

      But as above mentioned, the bodyplan for initial construction of a hull, they have either 10 or 20 stations with same distance (and fore / aft half stations or even quartered) I guess this is why they call it stations and not frames, because frames are rather on the final framing plan which indeed show each single frame in shape.

      Cheers,

      Axel

    • #39463
      AvatarIcare
      Participant

      Maryak:
      You’re right, distance between station can change at the very ends of the hull, but when it happens, you can see there’s something odd on the top view (the bow or stern will be pointing out in a aesthetic-displeasing way), then try to divide this station’s interval by two, and if it still doesn’t work well, you’ll have to guess the right distance by trial and error.

      Axel:
      When there are too many stations (I forgot to mention this eventuality), you can simplify the net (use less polygons) and let the software draw more than one station per mesh. I’m used to say about the meshed net “the simpler is the better”, because is easier to draw it and to modify it, too. 😉
      If you really can’t get the model’s stations profile fit the background image, you’ll have to add a row of meshes (depends on the curve’s complexity).
      I’ll try to post scrennshots on the next week.

    • #39464
      AvatarAxel
      Participant

      Hi Icare,

      thanks for the input again and well what you mentioned to Maryak, correct, an odd distance is not common and if it happened you can adjust it on the forcastle outline.
      Looking forward seeing your screenshots 🙂

      Cheers,
      Axel

    • #39465
      AvatarRobert Holme
      Participant

      An example of uneven spacing
      STYelta_Linesplan.jpg

    • #39466
      AvatarRobert Holme
      Participant

      An example of uneven stations Frame Spacing 1 ft 9 ins
      Yeltalines.jpg

    • #39467
      AvatarAxel
      Participant

      Very odd and uncommon, then is better to have the station arrangement on a top view as shown there or you align the stations according to the outline if no station markers.

    • #39476
      AvatarIcare
      Participant

      On Maryak’s example, stations 22 to 32 won’t give you very much information, furthermore, they would look like an unreadable big pack of lines, because they’d all look the same.
      The best is to have all three views (side, top, front/back).

      So, as promised, I’m back after refining my method. B)

      I found a strange bodyplan (large beam and narrow transom) and wished to know what such a ship can look like? So I modeled her just using her stations profiles. I imagine she was around 10 meters long and 3.7 meters wide. I think her transom was rounded (like on Meriak’s example), but creating rounded transoms is an other question, I’ll draw her a flat inclined transom.

      Ready?

      Fifteen screenshots are following

      Martin -our webmaster- is going to kill me for the space my files are using on the forum!

      Don’t feel at loss if my Delftship display doesn’t look like yours: I’m still using a five years old version, but if it works on my old version, it will do on yours, too.

    • #39484
      AvatarIcare
      Participant

      That’s the most boring part…
      Click’n drag again and again…
      Change the station and the polygons location…
      Click’n drag again and again…

      But finaly, I could get something acceptable. B)

    • #39485
      AvatarAxel
      Participant

      Hi! Many thanks for these steps how you got to the good result! I think I can try it the same way. Good to see such tutorial as a guide 🙂

      Cheers,

      Axel

    • #39486
      AvatarRobert Holme
      Participant

      On Maryak’s example, stations 22 to 32 won’t give you very much information, furthermore, they would look like an unreadable big pack of lines, because they’d all look the same.
      The best is to have all three views (side, top, front/back).
      .

      ??? Maybe you are confusing stations with frames i.e. 22 -32 consists of 3 station profiles not 10 all looking the same.
      STYelta_Linesplan.jpg

Viewing 16 reply threads
  • You must be logged in to reply to this topic.