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organic curves/beyond arcs and circles

Discussion in 'Tutorials and Tips from the Community' started by Kunkmiester, Jul 7, 2018.

  1. Kunkmiester

    Kunkmiester New Member

    I'm working on a project to build a model M1 Abrams, and will likely extend to doing numerous other tanks at points somewhere past actually getting a business started.

    big problem is most tanks have curved surfaces that don't have fixed radii. I'm looking at the glacis plate(front armor on the hull) on the Abrams, and things like the turret on the M4 Sherman and a few other places. This has similarities to making fenders and car parts where spline type curves are used. While some parts of the curves don't necessarily need to be well defined, I do need decent models that can have some dimensions fixed(for defining attachment points and scale stuff etc.).

    My Google-fu is failing me on getting a decent modern tutorial for this, most are like 10 years old, or not related. I'm also restricted in what material I can use to get data, since this is a commercial project, and can't always guarantee Ed Gruberman's model on Thingiverse is quite right, assuming Alibre can open it and let me turn it into a vacuformed part and accessories.
     
  2. bigseb

    bigseb Alibre Super User

    Post a picture of exactly what you want to achieve.
     
  3. WillAdams

    WillAdams Member

  4. Lew_Merrick

    Lew_Merrick Alibre Super User

    My argument is that we need a much richer set of curve entities available to us: 5-point conic curves, Wronskian curves, True Inolute curves, and the like.
     
  5. GIOV

    GIOV Senior Member

    Alibre is lack in B-spline & loft and specially fall to have a feature Tangent constrain between B-Spline and line or curves so the surface remain with little discontinuity. Here is a little example:
    upload_2019-11-20_21-41-59.png
    upload_2019-11-20_21-43-2.png
     

    Attached Files:

  6. WillAdams

    WillAdams Member

    Okay, I yield the point that this can be modeled in Alibre --- if I may revise my question:

    >How does one draw the profile of such an organic shape directly using the spline tool?

    (see my other post asking how one would draw the Alibre logo)
     
  7. idslk

    idslk Alibre Super User

    Hello WillAdams,
    also the "organic"-tools are not state of the art in Alibre, why do you want o use a screwdriver to get a nail into a wooden plank?
    Regards
    Stefan
     
    bigseb likes this.
  8. NateLiqGrav

    NateLiqGrav Alibre Super User

    I've never tried it but a bunch of people on the forums have found MOI to be a great "organic" shape software that works well with Alibre. http://moi3d.com/
     
    WillAdams likes this.
  9. WillAdams

    WillAdams Member

    It's been on my radar to try for a long while --- I wound up with Alibre Atom3D since it's being bundled with Carbide 3D Nomads and Shapeokos in their Black Friday sale this year:

    https://carbide3d.com/blog/2019/black-friday-2019/

    (as opposed to the Alibre Black Friday sale)

    https://www.alibre.com/black-friday-licenses/
    So the consensus is that Alibre only does arcs, circles, and rectangles, and the spline tool is limited to the shapes which it will naturally/willingly make (which can then be rotated or extruded --- are there other options?) and if one wants free-form organic modeling, use a different tool.

     
  10. DavidJ

    DavidJ Alibre Super User Staff Member

    At first glance the M1 Abrams hardly has a curve anywhere - nearly all angled flats. I would image that to keep manufacture fairly simple, complex curves would be avoided unless there was a very good reason.

    As bigseb commented above - can you give us an example of the shape needed? or at least indicate which aspects are proving problematic...
     

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