Hello, I am trying to get a linear family to flex incrementally to certain distances. I have written the equations and everything seems to flex fine in the family. But as soon as I load it into the project, It completely ignores my equation driven parameter? I have a feeling that it has something to do with the way a linear family is set up since I cannot delete the length parameter. Its really strange and illogical how it is behaving. I have attached the family. Please help!
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The Family is working "properly" in the Project Environment according to the Family. When you draw a linear Family in the Project, that determines the value of the "Length" Parameter in the Family. Since your Extrusion is constrained to the "Length" Parameter in the Family, your formula is being bypassed. You will need to create and additional set of vertical Reference Planes (left and right sides) that will be constrained by the "LengthCalc" Parameter, and then adjust the Extrusion and the Array to be constrained to those Reference Planes instead.
You will need to adjust your "Number of Holes" formula to reference "LengthCalc" instead of "Length". Also, your "Length Input" parameter currently holds no power - set the formula to "=Length" or substitute "Length" for "Length Input" in your primary formula and then remove "Length Input".
I put the family in and it looks like it stretches okay. Is it supposed to only expand in increments equal to the "Length of a Single Hole Cut".
Sorry, you won't be able to achieve what you are describing. It sounds like you are seeking the behavior of dynamic blocks in AutoCAD? The stretching action in Revit will always be arbitrary initially but if your formulas are well defined the family will adjust to be only an acceptable size afterward. You just won't get the notched or stepped sort of context you are looking for.
To the OP :
Maybe you need to change your plan. My comments:
1) It is not a good practice to array an extrusion. You should array a nested element instead.
2) It is not a good practice to put so many voids in a family. (Is it really necessary that the elements are voids? They could be just a representation with model lines (nested).
3) If you want a family to have a certain length that is determined by a certain module, make it be driven by an integer parameter that controls the number of elements in the array.
Items # 1 and # 2 affect the performance of the family. Have you noticed how long it takes for this family to load and regenerate when you create one instance? Do you want your projects to have their performance affected, waiting for instances of this family to finish regenerating?
The family you are making is a structural framing family, that is created in the project by two clicks, endpoint and startpoint. How can you predict how many holes are going to be in each instance? You can't put all the possible numbers in that extremely long formula that you wrote.
Isn't it better to control the length and number of items with an integer parameter instead of writing a formula with 62 embedded IF statements?
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