Applying a Family Type Parameter

[curiousspinningplates]

I have a question on a fairly sophisticated family that I've simplified to what you see in the attached RFA.

The issue is that I have two extrusions (extrusion, hollow extrusion) which are nested into my parent family (Problem Family). Revit has the capability to have families themselves as parameters - so if I want, I should be able to swap out hollow extrusion for extrusion and vice versa.

So - I've created a parameter called Extrusion and Type and then four types. I've brought in my extrusion and then placed, aligned and locked it to the height ref. plane so that it will move accordingly as the user selects the various types. 1'H Extrusion should move the extrusion family to 1' off the ground. 1' H Hollow Extrusion should have my hollow extrusion family 1' off the ground. But that's my problem - when I change my parameter (Extrusion Type) to Hollow Extrusion - it breaks. However there is no problem in adjusting the height - if I move to 5' H Extrusion, everything works fine - it's just switching from one rfa to another that seems to be creating a major issue.

I've seen the Revit Help document on this:
Creating and Applying a Family Type Parameter

No dice. Anyone have a clue how I can get this to work and what I'm doing wrong?

[twiceroadsfool]

An alternate method to get it to work is as follows: Set up a visibility parameter for "both" extrusions, or Nested families, or however many it is you are inserting. Then, you can set up an IF statement such that it checks which value a person selects, and the IF statement can drive whichever Visibility Parameter gets the positive value in that case. This works fine for scheduling too, and then you will not have the issue of the height constraint collapsing when you swap out the nested family from its parent family.

Steve Stafford has a great blog post on doing something similar, called "Make up My Mind."

http://revitoped.blogspot.com/2005/11/make-up-my-mind.html

I too, have issues with the Family Type parameters. Ive found that when you swap the family types out, the dimensions (and constraints) fall apart from the family that WAS there. For this reason, i dont use them in many cases, but id like to...

[Steve_Stafford]

When I took a look at your family I expected to find that the nested parts were each built/constrained so they flexed differently since that is a leading contributor to failure. Instead I found that I just needed to constrain the family again. I moved the nested family away from the reference planes and removed the constraints that Revit complained about breaking by doing so. (Using Move with Disjoin option will do it without complaints)

I then aligned the vertical centerline of the family to the center(left/right) ref plane. Tested, no worries...did the same for the horizontal and finally for the bottom of the extrusion in elevation. I experimented with changing the family types haphazardly and all works fine.

You must change the parameters in the Family Types dialog, not through the type selector. See if the attached is working the way you hoped? I also linked the Height parameter in both nested parts to the Height parameter in the host. I'm sure I messed up your parameters :smile:

[curiousspinningplates]

Steve-

Thank you, that did the trick. That was just an example file I sent that was going through the same issue I was having in a more complicated family - so no problems with any changes you've made...Thanks again.