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jdonovan-21-Visitor
1-Visitor
January 24, 2018
Question

replacing models without screwing up constraints and references??

  • January 24, 2018
  • 4 replies
  • 8893 views

using Creo2 ... simple example

Scenario:  upper level assembly p/n 12345.asm  ..... pcb assy with (5) connectors p/n pcb123.asm .... sheet metal panel p/n 6789.prt  ...... The cutouts in the sheet metal panel are created in the upper level assembly using the connectors in the pcb assembly as references.  (this is typical top-down parametric design process).

Case: Need to replace pcb assy with new part number ..... when I do replace command it makes me re-do the original placement constraints in the upper level assy and it also creates errors so that I need to basically re-do the sketches/references for the cutouts in the sheet metal panel.

I am a former Solidworks user and this type of thing was never a problem.  With Creo I can't figure out the proper way to do this without doubling my work (maybe the solution is there but I just can't find it).

4 replies

S
23-Emerald III
StephenW23-Emerald III
23-Emerald III
January 24, 2018

Using the replace command, select the "unrelated component" option (also good to uncheck "remember these components" unless you want a permanent reference to remain on how to replace the parts in the future).

Select your new component.

Use the "edit reference table" button. Creo makes an assembly of the 2 parts, and generates a list of the references used by the existing part.

Choose the coresponding reference for each on the new part.

replace.jpg

    D
    DaveMartin16-Pearl
    16-Pearl
    January 24, 2018

    "it also creates errors so that I need to basically re-do the sketches/references for the cutouts in the sheet metal panel"

     

    Are you using Project (formerly Use Edge) and/or Offset in Sketch mode a lot to reference external components? If so, that is not a great design practice.

    J
    jdonovan-21-VisitorAuthor
    1-Visitor
    January 24, 2018

    Just creating cutouts in sheet metal using the edges of the connectors as references … ie. rectangular cutout – right edge of cutout 0.5mm off of referenced edge of connector; top edge of cutout 0.5mm off of referenced edge of connector etc etc

    D
    DaveMartin16-Pearl
    16-Pearl
    January 25, 2018

    So are you using Data Sharing Features like Copy Geom, or are you selecting the edges from the other parts directly?

     

    If the latter, are you breaking the External References in the sketch?

    J
    jbob12-Amethyst
    12-Amethyst
    January 24, 2018

    Just to add onto using the replace by unrelated component, I would do the replace command in your upper level assembly and not the lower level.

    J
    jhaston-31-Visitor
    1-Visitor
    January 30, 2018

    @jdonovan-2, I thought the question you posted here was good, interesting, and I wanted to try to help you out.

     

     

    I didn't have the time to formulate my answer when you posted and had to wait to consider it and decide the best way to answer. In the meantime you got frustrated and blew-off some steam. I'm sure we all did that at some point.

     

    Back to your question.

     

    Top-down design is easily misunderstood. Perhaps I misunderstand it myself.

     

    Attached you will find a procedure, 2 pages, describing the steps performed in a short video you can find here https://youtu.be/SiG2UikQs64

    Sorry, cheap video and no sound.

     

    From the procedure and video (only 12 minutes), I hope you can re-create the model and learn about some important features of 'top-down' design using Creo, from my understanding anyway.

     

    The example introduces the use of parameters, relations and program editing, using a simple example of the kind you described. I hope it demonstrates a method you can learn and develop to suit more complex cases.

    The final model in this example allows you to choose between two assembly configurations, when regenerating the top-level model.

      J
      jdonovan-21-VisitorAuthor
      1-Visitor
      January 31, 2018

      thank you for your input, helpful .... appreciated.

      One more question: Do you, or anyone else out there, find yourself using top-down design practice with Creo2? or do you shy away from it? and if not using it, why??  ..... the reason I ask is because I took a quick seminar trying to learn Creo2 and the guy who was giving examples kept on saying "once you get the design complete, go back in and delete all of your references etc etc" ..... I couldn't understand what he was trying to convey.

      Thank You again.

        D
        DaveMartin16-Pearl
        16-Pearl
        January 31, 2018

        I have used Top Down Design with External References in multiple industries, including consumer electronics, unmanned aerial vehicles, and aerospace.

         

        There are pros and cons to using External References. When used improperly, they have severe negative repercussions.

         

        I believe your instructor was irresponsible for blindly advocating deleting all references, which would be bad modeling and might not be in accordance with your Design Intent.

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