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Make flexible - unexpected behaviour

Discussion in 'Using Alibre Design' started by OrjanB, Jun 30, 2020 at 4:40 PM.

  1. OrjanB

    OrjanB Member

    I have an assembly consisting of several subassemblies.
    Each subassembly is, when originally made as assembly, constrained with parts that can be moved. (Linked together)
    These assemblies become subassemblies when placed in a new assembly, but now as fixed parts, no movement is possible.
    Then to the point:
    I go to the explorer, find a subassembly and activate «make flexible»
    Now I expect the subassembly to behave as if opened as assembly in separate window.
    This is not the case. When I activate «make flexible» the parts become unconstrained and must be reconstrained in the top-assembly.
    Am I missing something?
    Added info: The assemblies are originally step-files from external sources and constrained by me.
    Could this be the reason?
     
    Last edited: Jul 1, 2020 at 9:26 AM
  2. Lew_Merrick

    Lew_Merrick Alibre Super User

    Orjan -- Flexible only applies to a single level of UsedOn Assembly. It does not apply to any "UsedOn-UsedOn" level of Assembly -- this is something about which I have been "complaining" for more than a decade. -- Lew
     
  3. OrjanB

    OrjanB Member

    Lew:
    Not sure I understand you correctly.
    I have a two-level assembly: Top level and subassembly, not level-on-level.
    Then it should work(?)
     
  4. JST

    JST Alibre Super User

  5. NateLiqGrav

    NateLiqGrav Alibre Super User

    Yes and I think that (for some reason) assembly patterns break the positions of the made flexible subassembly. Also a problem with configurations if I remember correctly.
     
  6. Lew_Merrick

    Lew_Merrick Alibre Super User

    Hi Orjan -- To confuse thing someshat I use a terminology derived from US military traditions. (1) A Project is what many call a Top Assembly. (2) A Project is made up of Major Assembles and Parts. (3) A Major Assembly is made up of SubAssemblies and Parts. (4) Sub-Assemblies are made up of SubSubAssemblies and Parts. (Etc.)

    If I make a (say) SubSubAssenbly Flexible within a SubAssembly that definition cannot and will not translate into the "next higher" Assembly. This is a limitation that has existed (I believe) since Flexible was introduced to Alibre. Prior to V21 I had to create "Hidden Linkages" to makes things such as pneumatic and hydraulic cylinders work correctly. Such component Assemblires can only be introduced at the Project level Model and have them work! My argument of many years is, "Once declared Flexible all transmission "u[" the Model Tree should be flexible." -- Lew
     
  7. idslk

    idslk Alibre Super User

    are the parts in your subassembly constrained or only fixed?
    Can you post your assembly as a *.pkg?
    Have you tried the file in This Post ?

    Regards
    Stefan
     
  8. JST

    JST Alibre Super User

  9. DavidJ

    DavidJ Alibre Super User Staff Member

    This issue has been confirmed with JSTs files from an earlier support ticker. It has been passed to Development for investigation.
     
  10. OrjanB

    OrjanB Member

    The parts in the assembly (a push-pull handle) are constrained before placed in the top-assembly as a subassembly.
    I now see that this assembly consist of several subassemblies and that this fact probably is the reason for the problems.
    The assembly was imported as a .stp-file. When this file was opened in Alibre the subassemblies occurs.
    I have made a special assembly (enclosed as package) to illustrate. This is just a part of the total construction.
    So Lew: You are right: There is a level-on-level situation.
     

    Attached Files:

  11. idslk

    idslk Alibre Super User

    Hello Orjan,
    your first level assembly (sokkel and 001_Desta....) was constrained, the second level (001_DES... and his sub assemblies) was constrained, but the 4 subassemblies in them selfes were not contrained. That makes them "floating"...
    In this appended package i tried to contraint everything...hope it behaves like expected.
    Regards
    Stefan
     

    Attached Files:

  12. OrjanB

    OrjanB Member

    Hi Stefan,
    Thank you for investigating. You confirm my findings concerning the push-pull device with parts.
    The part named sokkel, being the first part in the top assembly, is constrained by me.
    I always constrain the first part to the original planes in top assembly in order to avoid «floating» in space.
    Earlier I have sent Alibre a wish: Make a function that, if wanted, in one action constrains the first part to the original planes.
    In Inventor this is possible.
    Regards
    Orjan
     
  13. JST

    JST Alibre Super User

    You can always use the "anchor part", which is what I do. It may be what you are doing, and may sometimes cause issues, but it is do-able and un-doable in one click.
     
  14. OrjanB

    OrjanB Member

    I know, but by constraining original part planes to original assembly planes the part is correctly orientated when you later make drawings/dimensions.
    With anchoring only there is a danger for the part not to be perpendicular to the sheet.
     
    Last edited: Jul 3, 2020 at 5:10 PM
  15. JST

    JST Alibre Super User

    But you have full control of the orientation on the drawing sheet, so it makes no difference. A couple more clicks only.
     
  16. OrjanB

    OrjanB Member

    You are right if you place the first part in the assembly on the first click and without any rotation.
    But if you unintentionally rotate the part after first placing it will not appear correct on the drawing sheet.
    And if you by accident deactivate the anchoring the mess will start.
    After years with Inventor I prefer constraining first part to the original planes in the assembly, thus reducuing risk for mess later in the work.
    As mentioned earlier, in Inventor this is done by one click .
    This discussion on not regarding right or wrong, more a matter of preferred workflow.
    However, I suppose Inventor has made this function due to feedback from users.
    Regards
    Orjan
     
    idslk likes this.

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