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Rack Constraint Index Problem

Discussion in 'Using Alibre Design' started by temartin, Jul 31, 2020.

  1. temartin

    temartin Member

    When I use a mechanical rack constraint, I find that each time that I open the file, the rack constraint "indexes" by 360 degrees of the pinion.
    I have also found that it indexes each time I suppress and then re-enable the constraint.
    If I enable and suppress the constraint several times, the rack will be out in space on the model.
    Am I doing something wrong or is this a bug?
     
  2. idslk

    idslk Alibre Super User

    Hello temartin,

    it might be a serious problem with the gonkulator, to speak with "Lew's words":D
    Jokes aside...it would be benefical to append a package of your design.
    Without it is nearly impossible to imagine what's going on on your side.

    Regards
    Stefan
     
  3. Lew_Merrick

    Lew_Merrick Alibre Super User

    Hi Stefan -- I had a (now deceased) uncle who spent much of WWII working in the Manhattan Project. The only "description" of what they were working on whilst "off site" was "Gonkulator." That is where my use of the term comes from. My uncle thought it hilarious that "my generation's term" for such things was "The Looking Glass World." -- Lew
     
  4. temartin

    temartin Member

    This rack is part of a more complex machine.
    Let me see if I can replicate the problem in a smaller file.
     
  5. temartin

    temartin Member

    Attached is an assembly with the irrelevant parts taken out.
    If you suppress and the reactivate the Rack(1) constraint, the rack advances each time you do it.
    It also happens each time the file is opened.
    Please treat the file as proprietary and a trade secret.
     

    Attached Files:

  6. DavidJ

    DavidJ Alibre Super User Staff Member

    Try changing the Pinion definition in the constraint to a circular edge rather than a face.

    It might just be the re-definition that resolves it, rather than something magical about using an edge.
     
  7. temartin

    temartin Member

    I have tried several combinations of edges and reversing relative motion.
    It is still doing it but oddly not every time.
     
  8. idslk

    idslk Alibre Super User

    upload_2020-8-4_21-21-44.png

    Hello temartin,

    in the first try (original package) it has the described movment.
    Second try i've changed the constraint partners.
    I've tried the light blue highlighted edges.
    In addition to this, i've supessed the angle constraint (only to see full motion...).

    Regards
    Stefan
     

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