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Reversing the return of driving parameters

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    Reversing the return of driving parameters

    I'm experimenting with an idea at the moment, but have come up against a (small-ish) hurdle.

    I have a family I want to control dimensionally by both formula and grip-control - but can't seem to get the two to behave (together).

    I've the formula part down; I've instance (length) parameters, ie. "Y" driven by the product of a type (length) parameter "GRID_UNIT" multiplied by an instance (integer) parameter "GRID_X"... but when I use the grip-control (in a model environment) "Y" changes, but the formula appears to get overridden/forgotten... until either "GRID_UNIT" or "GRID_Y" are then editted, and then "Y" resets to follow the rule.

    How do I get the grip-control talk/respect the formula so edits to the family can be done in either way and the parameters are return true? Dummy parameters? If so, for which, and how?
    Attached Files

    #2
    looks like Y should drive either the grid spacing or both the grid number and spacing, you set it up the other way around, probably for a reason? And for a variable Y, should spacing or grid number change? Revit won't do the choosing for you.

    Y is an EP, so if it drives grid number and grid spacing have to be element parameters. in your current setup, it suprises me that your grips on Y still show up, it is essentially constrained by type parameters. if Y was itself a TP, grips would not show up. What you are butting your head agains here is that EP's can never override TP's... except if you override them without revit noticing, it would seem. if I were expensive software, I would be so embarrassed that i would pretend it never happened.

    oh, and it can indeed be done with dummy parameters, but you have to tell revit which value to use for the dimension label, by y/n+if or some other formula.
    Last edited by ekkonap; September 20, 2011, 08:25 PM.
    There must be a better way...

    Ekko Nap
    Professional nitpicker, architect, revit consultant, etc.

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      #3
      Originally posted by ekkonap View Post
      looks like Y should drive either the grid spacing or both the grid number and spacing, you set it up the other way around, probably for a reason?
      And for a variable Y, should spacing or grid number change? Revit won't do the choosing for you.
      Ideally, "Y" should only ever be an output; the sum of number of grid units * grid unit size or the result of a grip-pull...

      The reason for all this is "we" tend not to say :
      "this building will be 50m long"
      but instead, arrange form by
      "this building will be 10 units long"
      or
      "this building will be from here to there"
      during v.early conceptual design.



      The grid unit size can change depending on our choice of construction, hence why it needs to remain a (editable) fixed constant, whereas it's accepted the number of units (that make "Y") will vary, but ideally remain an integer.

      Originally posted by ekkonap View Post
      in your current setup, it suprises me that your grips on Y still show up,
      I don't know how it's working either! :laugh::crazy:
      Last edited by snowyweston; September 20, 2011, 08:31 PM.

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        #4
        EP_grid number=round(TP_fixed grid size/gripsY)
        massY=if(EP_gridfixedyn, TP_fixed grid size*EP_grid number, gripsY)
        There must be a better way...

        Ekko Nap
        Professional nitpicker, architect, revit consultant, etc.

        Comment


          #5
          Originally posted by ekkonap View Post
          EP_grid number=round(TP_fixed grid size/gripsY)
          massY=if(EP_gridfixedyn, TP_fixed grid size*EP_grid number, gripsY)
          Sorry dude I don't follow.

          It's easier (for me) to picture formulae as "steps", ie. "add this first, divide that by this, take that and multiply by that" etc. That said, I could just be getting weary of a day infront of a computer...

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            #6
            Originally posted by snowyweston View Post
            Sorry dude I don't follow.

            It's easier (for me) to picture formulae as "steps", ie. "add this first, divide that by this, take that and multiply by that" etc. That said, I could just be getting weary of a day infront of a computer...
            ok, you need a different parameter for your grips and for what drives your element dimension, plus a y/n or equivalent formula to let revit choose between the fixed grid sice and the variable grid size.

            duty, in it's cutest 1,5 foot form, calls. more tomorrow
            There must be a better way...

            Ekko Nap
            Professional nitpicker, architect, revit consultant, etc.

            Comment


              #7
              Originally posted by snowyweston View Post
              ..I have a family I want to control dimensionally by both formula and grip-control - but can't seem to get the two to behave (together)..
              It is possible when you have a length and a parameter in the formula that produces X, being X an instance parameter. Something like X = A * 3.0 , then, if you change the value of A or the value of X both of them will update, both in the family editor or in the project by dragging shape handles. But the situation you have in this mass family is something like X (instance/length) is equal to A * B , which makes your wish impossible, because, first, now X becomes unavailable for editing in the family editor and, then, in the project, the length of X loses the shape handles. Imagine if you could change the value of X, how could Revit calculate the new values of A and B?
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