A little while ago I was asked how to create a parametric cooling coil to go inside an air handling unit (AHU) family. First up, I would advise that if you’re considering doing this too keep in mind what level of detail (LOD) that you or your company models to and also to take into consideration what value families detailed to this extent will or will not add to your project.
With that though, I decided that because the solution wasn’t immediately obvious and because there may be legitimate reason for someone to create something similar I put together a quick demonstration on how to make it work.
I must admit, when I first started creating this family I was a little worried as the theme song for Mission Impossible started playing on the radio! In the end though it is quite simple to achieve although not immediately obvious to the end user what the solution may be.
There are two methods that you can use to make this work utilising a nested family or directly arraying the sweep. Usually if you find that parametric objects are not behaving the way that they should in Revit most of the time the issues can be resolved by nesting the geometry in another family; you would control the dimensions of the sweep in the nested family and the array in the host.
If you are going to directly array the sweep within the family the trick is to align and lock the quadrant of the circle at the end of the swept path. Most people will try and align and lock the outer edge of the 3D element itself, but this will not work because our sweep profile is a circle it has no edges that can be aligned.
The second option is easier to control the array. As mentioned above you simply need a reference plane within the nested family that you can use as a base to align your array. Usually if there are any odd lingering issues nesting the complex objects is an easy way to eliminate them.
You will see the in demonstrations and the files themselves that for the first option I have made all the parameters in the family type parameters as these would be in the AHU family itself and would be controlled by a family type. In the second option, I have made the parameters in the host family type and the parameters in the nested family instance so they can be driven from the host.
You can download the example files here:
And watch the video demonstrations for each option as well
[su_youtube url=”https://www.youtube.com/watch?v=OGnfa1HBtlY”]
[su_youtube url=”https://www.youtube.com/watch?v=t3zmZWnX41Q”]