Offset surface – flipped normals

DELFTship forum Hull modeling Offset surface – flipped normals

This topic contains 5 replies, has 3 voices, and was last updated by  iosif gross 4 weeks, 1 day ago.

  • Author
    Posts
  • #43562

    Johannes Theron
    Participant

    I am trying to create some plank thickness in order to accurately draw the frames. However, the surface is always added to the outside of my hull. This happens also after I flip the normals to point inwards.

    Can anyone help?

     

    Jan

  • #43564

    iosif gross
    Participant

    I would like also to know how to do that, but I am using the frames of my small bats as is while adding the planks thickness. The hydrostatics are given with the skin.

    Best wishes

    Iosif

  • #43565

    Icare
    Participant

    Hi Johannes!

     

    Did you try to use a “negative” distance? (positive -> outward… negative -> inward).

    If it works, you may get a strange behaviour of this operation when the hull curvature’s radius reaches the offset surface’s distance, in the region of the stem or in the sternpost for example (the surface may cross itself).

     

    Drawing the planks’ inner face may be tricky because Delftship will consider them as a supplementary surface to be developped (in the cutting draft) and to be taken in account (in the weight & buoyancy calculation).

    I strongly suggest you draw these extra surfaces in an other layer using a special setting to have them NOT taken in account in the cutting draft and buoyancy calculation).

  • #43566

    iosif gross
    Participant

    Thank you Icare, I was waiting your answer 🙂

    It convincing me to continue as I am doing right now

    Best wishes

    Iosif

  • #43568

    Icare
    Participant

    Iosif said:

    It convincing me to continue as I am doing right now

     

     

    It depends on what you’re expecting from the software Delftship.

    Since you’re building boats, you need the most efficient result in buoyancy calculation and draft drawing.

    But Delftship can be used for simple illustrative purpose, without any worries of physics, too.

    I already used it to explain the kind of poster for a show I was imagining, to show a cremone/espagnolette however I hadn’t any camera, and to draw an electrical connection diagram.

    And, concerning Delftship‘s main puropose, naval design, when preparing a simple skiff you may wish to draw the planks’ inner face, just to know the cross pieces’ profile and how to cut them (outter profile minus the planks thickness and eventually minus the inner reinforcing parts).

    Hey! 💡 Don’t you feel this latest sentence needs a sketch? Delftship can be the convenient tool. 😎

     

    • This reply was modified 4 weeks, 1 day ago by  Icare.
  • #43570

    iosif gross
    Participant

    The point is that with planking of plywood between 4 to 12 mm the boat size and the displacement changes are very small. I am taking in consideration the planking addition is size when I am making the preliminary design.

    My designs are between 2.3 meter and 8.5 meter on deck. I am not planning anything bigger in the near or far future 😀

    Best wishes

    Iosif

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