Maxsurf-Have a design created from markers, need to modify it...

Discussion in 'Software' started by GavinM, Oct 6, 2011.

  1. GavinM
    Joined: Sep 2011
    Posts: 10
    Likes: 1, Points: 0, Legacy Rep: 40
    Location: Central Coast, CA

    GavinM Junior Member

    Hey Everyone,

    Next few questions,

    I have tried to give as much info as possible but please let me know if you need more info or something clarified. I will post some screenshots tonight to try to clarify some things. Also, I'm using Maxsurf Academic if it makes a difference.

    Question 1

    I have a .txt file with station coordinates that I brought into maxsurf by creating 450 markers, and then copying and pasting my data from excel into the markers table. This worked almost perfectly to bring my design into maxsurf except that the bow and stern are kind of weird. My first station is all along the centerline and defines the shape of the bow when viewed in profile view, and my last station is also along the centerline and defines the shape of my stern when viewed in profile. The other stations define the shape of the hull at 1' intervals. Anyways, from stations 1 to 19 (with station 1 being 1' aft of the forwardmost point of the bow) looks great. When I try to complete the surface to include the bow and stern stems though i get more or less triangular divots in front of station 1 and behind station 19. Any idea how to get around this and have a smooth shape?

    Question 2.

    I want to modify this shape to create a new design. I generated a design grid and a trimesh surface but I don't know how to modify these to my design. Essentially all I want to do is make the canoe slightly narrower, round the bottom very slightly, and maybe add a chine... Can anyone give me some general direction to help me along with that? I have about 1 week left to do this and I haven't made nearly as much progress as I would have liked over the past 3 weeks... I know that I probably need to add some control points but maxsurf won't let me add any control points, or view curvature, etc with what I have currently which is a design grid and trimesh surface generated from the 450 markers.

    Thank you very much in advance,

    GavinM
     
  2. dougal_harris
    Joined: Oct 2006
    Posts: 5
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    Location: margaret river

    dougal_harris Junior Member

    Hi Gavin,
    Trimesh surfaces are only for if you wish to import an existing design in for use in Hydromax (for example to create a stability booklet). If you wish to make modifications then you really need to be using NURBS surfaces. If you have the markers imported and as assigned to stations then fit curves through the marker stations and skin a surface across that. The surface can then be modified via its control points. Unfortunately NURBS surface modelling takes quite a bit of practice to get efficient and proficient. Good luck.
    Dougal.
     
    1 person likes this.
  3. GavinM
    Joined: Sep 2011
    Posts: 10
    Likes: 1, Points: 0, Legacy Rep: 40
    Location: Central Coast, CA

    GavinM Junior Member

    Thanks!

    I have a few curves through the markers now (running longitudinally down the length of the canoe) and I will see about skinning a surface to them now.

    Will see how it turns out.

    GM
     
  4. GavinM
    Joined: Sep 2011
    Posts: 10
    Likes: 1, Points: 0, Legacy Rep: 40
    Location: Central Coast, CA

    GavinM Junior Member

    Well we are getting there. I fit curves to marker stations, broke the curves near the chines along the sides, locked the design, and tried fitting a surface to the curves but then I got some pretty weird stuff. Attached is a PDF with some screenshots, everything look normal to you guys or do you see an obvious mistake? Keep in mind what I would ultimately like to do is narrow the design and maybe round the bottom a bit and add a chine or two.

    I tried skinning curves using settings for exact fit and by manually defining the stiffness and number of columns and rows also. I also tried sorting by selection order and longitudinal position to no avail...

    Thanks for all the help so far, definitely feel like I'm almost making progress now.

    Cheers,

    GM

    Also attached the .msd file just in case.

    Thanks again.
     

    Attached Files:

  5. DCockey
    Joined: Oct 2009
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    Location: Midcoast Maine

    DCockey Senior Member

    I'm not a Maxsurf user but my guess is the twist is due to reversed direction on some of the curves.

    In Rhino using the Loft command twisted surfaces result when some of the curves are selected near one end, and the other near the other end.
     
  6. nitinoena
    Joined: Mar 2012
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    Location: India

    nitinoena New Member

    I am student i was trying to make surface from markers -> curves .... I am also getting this twisted surfaces near stern and bow
    Are there any sources from where i can learn about developing surfaces .
     

  7. zeroname
    Joined: Oct 2008
    Posts: 276
    Likes: 5, Points: 0, Legacy Rep: 90
    Location: Europe

    zeroname Naval Architect

    Check the order of points are correct or not. There is a good chapters and video tutorials in www.formsys.com check there, you can solve it.
     
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