use of POLYCAD naval design software

Discussion in 'Software' started by JFD, Jan 30, 2020.

  1. JFD
    Joined: Jan 2020
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    Location: France

    JFD New Member

    HI,
    Who can help me ? I try to use POLYCAD 10-4 for designing boats and I would like to know if some of you use alos this naval design software because I need some help about some shape drawings.
    I live in France
    Thank you for your reply
    JFD
     
  2. pafurijaz
    Joined: Dec 2016
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    pafurijaz Senior Member

    Hi I tried to use it, but I only managed to loft the curves to make a hull, From what I have seen, it has all the tools to generate complex surfaces, The only flaw for now does not support trimmed surfaces, I use a workflow that starts from Blender where I create the hull with the subdivision surfaces, then go through FreeShip and then import my hull in IGES in PolyCAD, or in Rhinoceros to create a precise model to work on, but I use PoliCAD for some hydrostatic calculations and other things such as offset tables and more.
     
  3. pafurijaz
    Joined: Dec 2016
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    pafurijaz Senior Member

    Probability you know these video anyway if no, they can be help maybe.



     
  4. Alexanov
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    Alexanov Senior Member

    Looks little bit complicated to use many different products. Look at https://www.shmexpert.com/post/shape-maker-cad-export-files it can be probably more simple way.
     
    pafurijaz likes this.
  5. JFD
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    JFD New Member

  6. Alexanov
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    Alexanov Senior Member

  7. Andy
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    Andy Senior Member

    Im playing with Polycad just now and I really like it, very powerful and some clever approaches to the usual problems. Its very parametric too which is nice. X-topology is a kind of almost Tsplines like approach but using lines from which surface patches are automatically constructed with continuity determined by the initial lines. There is a Polycad help site with tutorials which oddly isn't linked to from the main page...google it?
     
  8. sujeethmonu
    Joined: Jan 2013
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    sujeethmonu Asst Professor(mech dept)

    Hello everyone,
    There seems to be a serious error in the calculations of PolyCAD hydrostatics. PFA of hydrostatics calculation table.
    At draught (T) of 150 mm, displacement is 224.1 kg and TPC=2351020.25 kg/mm.
    At T=151mm, displacement is 225.6 kg.
    So how does TPC which is in kg/mm correlate?

    I similarly created a model in delftship and performed hydrostatics and results are attached as well which is correct.
    example:
    At draught of 0.05m, displacement FW & displacement seawater is 0.035 tonne with TPC=0.021 tonne/cm.
    At draught of 0.06m, displacement FW & displacement seawater are 0.057 & 0.059 respectively which approximately correlates to TPC=0.021 tonne/cm at 0.05m draught.

    Can someone please throw light on this issue in polycad?
    I switched to polycad from delftship to design small boats as a hobbyist but have a concern regarding the calculation part.
     

    Attached Files:

  9. sujeethmonu
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    sujeethmonu Asst Professor(mech dept)

    Please take a look at my polycad and delftship hydrostatic images, since you are using polycad for hydrostatics calc it might interest you as well.
    Thanks in Advance
     
  10. pafurijaz
    Joined: Dec 2016
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    pafurijaz Senior Member

    Can you share the file? I can try check if there is some problem on boats and in the relative positions in the 3D space that make difference on the result, and make some times errors.
    But I'm not an naval engineer and I'm newbie on this fields.
    Anyway below a boat with DELFTShip and the same on PolyCAD, maybe these can help you..

    kn_ds.png kn_pc.png
    below result with high subdivision surfaces
    df-hy_h.png

    below result with mid level subdivision surfaces
    df-hy.png
    and PolyCAD
    PC_hy.png
     

    Attached Files:

  11. sujeethmonu
    Joined: Jan 2013
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    sujeethmonu Asst Professor(mech dept)

    Yeah the results what i see in polycad is showing correct TPC. Please check it. It'll be of great help in my learning process. seems like I have done something seriously wrong. Also, how to change the units in PolyCAD. mine is in mm and kg.
     

    Attached Files:

  12. pafurijaz
    Joined: Dec 2016
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    pafurijaz Senior Member

    Hi the problem is the scale I changed and now it should be fine,
    as far as I understand PolyCAD performs all calculations in meters or feet,
    this is probably a bug, I changed the scale from mm to meters and reset the values, now it seems to work, this I think is obvious, since it becomes complicated on these dimensions to take into account 1mm more or less.
    pc_into_m.png

    Maybe I'm wrong but it could also be that you filled in the fields in the wrong way using the comma and not the semicolon, but hydrostatic calculations are done in meters and not in mm. at least in my version.

    Here the inconsistency on units
    Hy_pc.png
     

    Attached Files:

    Last edited: Jun 9, 2020
  13. pafurijaz
    Joined: Dec 2016
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    pafurijaz Senior Member

    you must select the scale command and then the menu appears at the bottom right where you can change the unit of measurement

    scpl.png
     
  14. pafurijaz
    Joined: Dec 2016
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    pafurijaz Senior Member

    Seem I have the same result even into mm setup, I changed the hull and joined the surface to the transom but that seem the same hydrostatic result of yours file

    new_hull.png

    Below the same file with units in meters
    hull_mt.png
     

    Attached Files:

    Last edited: Jun 9, 2020

  15. sujeethmonu
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    sujeethmonu Asst Professor(mech dept)

    Just checked.. Thanks a lot. I even mailed marcus developer of polycad about the same. Will inform him about this. probably he will fix it. I feel polycad better than delftship or freeship. Whats your opinion on it to start learning basics of hydrostatics and modeling simple boats?
    Without your help I would not be solving it on my own. Thanks again.
     
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