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lhoogeveen17-Peridot
17-Peridot
September 4, 2015
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Switching Unit Systems with Parameters that have units

  • September 4, 2015
  • 20 replies
  • 7362 views

Is there a way to hard code Parameter Units to get ignored when switching units systems? I have a couple Parameters driven from Relations (e.g. WT_LB, MASS_KG, VOLUME_IN, and VOLUME_CM) and I would like them to always be in lbm, kg, in^3, and cm^3. Switching from in-lbf-s to mm-kg-s changes only the in^3 but changing back changes kg and the now mm^3.


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Best answer by TomU

You have to play games and manually convert from one system to another with unit less parameters.  See this: Feature Parameters in Repeat Region (BOM Table)

20 replies

TomU23-Emerald IVAnswer
23-Emerald IV
September 4, 2015

You have to play games and manually convert from one system to another with unit less parameters.  See this: Feature Parameters in Repeat Region (BOM Table)

    lhoogeveen17-PeridotAuthor
    17-Peridot
    September 4, 2015

    Tom Uminn‌

    I'm testing your method right now. It looks pretty flexible and hands off as well is easy to copy into legacy parts without having to turn on or define units to parameters. Our start parts calculate from model tree analysis features rather than using the MASS_PROPERTY_CALCULATE AUTOMATIC config setting. Just the way we've always done it. Do you know if analysis feature relations can be set to 'Post Regeneration'? Doesn't seem like it should be able to since it's in the model tree.

    Thanks,

    Luke

    dgschaefer21-Topaz II
    21-Topaz II
    September 4, 2015

    Analysis features run at their point in the regen cycle.  Same with relations buried in sketches.

    By using analysis feature or the pre- and post-regen areas of the relations dialog, you can control when any given equation gets calculated.

    dgschaefer21-Topaz II
    21-Topaz II
    September 4, 2015

    When you set the new units you are presented with this dialog:

    Capture1.JPG

    Click on the "Parameters" tab, There you'll find a list of parameters that are defined with units in the current unit system.  Look for any unit driven parameters that you need to remain in their existing units and set them to "ignore".

    Capture2.JPG

    In my case, the first three should change with the unit system, the other two I need to stay in pounds & inches respectively.

      lhoogeveen17-PeridotAuthor
      17-Peridot
      September 4, 2015

      Doug,

      Can that get set as the default so every time someone switches it would remain IGNORE'd? It resets every time for me. I'm reworking our start parts and would like all future switches to be ignored.

      Thanks,

      Luke

      dgschaefer21-Topaz II
      21-Topaz II
      September 4, 2015

      No, as far as I know, you need to review that list every time you change units.  In my experience, a unit change doesn't happen that often

      Sounds like a great Product Idea request.  Another would be nmot to bury those unit driven parameters in another tab, but display them right in the main dialog so they are harder to miss.

      lsrutkowski1-Visitor
      1-Visitor
      September 4, 2015

      Maybe I am missing something here, but why not just drop a mass properties feature into the footer and define your alternate parameters there.  User parameters defined in a mass properties feature can have units assigned and will retain their units when the units of the model are changed.  Being in the footer means that the mass properties are automatically calculated at the end of the part regeneration.  I added this to all of our start parts a while back so it is already there.  For the transition, I had a mapkey set up and also passed out a set of instructions so the engineers could fix any problem files in their current projects.

      Capture.PNG

      lhoogeveen17-PeridotAuthor
      17-Peridot
      September 4, 2015

      Larry Srutkowski‌

      What happens when you switch units systems on your part with this setup? It's a common enough occurrence for us. Also, I'm not sure how to create local parameters from Analysis features.

      My code above seems to work great for defining regardless of units system... except Sheetmetal Relations don't work with things like [lbm].

      Thanks,

      Luke

      lsrutkowski1-Visitor
      1-Visitor
      September 4, 2015

      When you switch units, the default units of the model will change, but the calculated units are defined in the parameters, so Pro|E / Creo will automatically convert the exist value to the requested unit of the user parameters.

      Now that I read that sentence again, it does sound a bit confusing...

      The attached PDF pages are from our old WF4.0 work instructions (I cut out the non-essential information).  The same method works for Creo with one minor change: before you set the units of a parameter, you need to define the type of unit in the preceding column (if you look at my previous post, you can see where the column before the units says "mass").  I am guessing that PTC did this so you do not have to scroll through a list of 30+ units.

      As for calling the units, you need to call &<parameter>:<feature ID number> or &<parameter>:FID_<mass property name>.

      lhoogeveen17-PeridotAuthor
      17-Peridot
      September 8, 2015

      I'm getting a weird situation where the code listed above works for .ASM and a solid .PRT but not for a sheetmetal .PRT. It doesn't seem to recognize the units in the relations. Is this normal with sheetmetal or a bug with Creo 3? I'm running Creo 3.0 M010.

      Never mind. Relations>Utilities>Unit Sensitive needs to be  turned on.

      150908 Start Part Relations - Sheetmetal Part Weight Issue.jpg

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