Nested Families vs Assemblies

[smbrennan]

Ok I'm new to Revit development, so please bare with me here as I stumble my way through.

I am trying to create a family with interchangable parts (at the moment I'm trying nested families). However, I want every family to have limitations based on other components (If one family type is this, then this family type must be one of these types). I want every instance of this family to have full flexibility. I also want every part to be schedulable, not only into a BOM, but also an "assembly schedule."

Also, the 3D gemoetry is not critical for this. It would be nice to eventually get a visual representation, but I'm sure processing power will be limited, as there can be several hundred of these nested families in a single project.

Where I'm stumped, is trying to determine the best method to do this. I've read obout nested families with Shared parameters, I read about assemblies. I've also thought about making a generic family with parametetrs that via text fields call out the different components.

Does anyone have any recommendations?

[CoreyDaun]

Could you provide an example, including what additional options you would want to restrict?

[smbrennan]

I want to create a (parent) family that contains the possibility of 3 electrical devices (receptacles, tele/data, light switches, etc). These devices would be nested families. The parent family would also contain other electrical families for the different junction boxes available.  Each junction box available will have it's own set of pre-defined trim rings available. 

The purpose of this is to get an accurate BOM for all wall rough-ins, while providing the most flexibility, but still limiting selections to real-life limitations (there are 4 common junction boxes, they come in 2 different LXW dimensions (4"x4" and 4-11/16x4-11/16), and those two types have 2 different depths (1-1/2 & 2-1/8). However, the trim rings are sized to the LXW dimensinons, and have varying depths (flat, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2).

As I'm thinking about it, it's almost as if I should organize the families as this:

Main Assembly

  - Device #1

  - Box #1 Type

      - Trim Ring Size

  - Device #2

  - Box #2 Type

      - Trim Ring Size

  - Device #2

  - Box #2 Type

      - Trim Ring Size

The box types would be separate families per the LxW dimensions, thus allowing a limited selection of Trim Ring sizes. When the parent family is loaded, users will only have to select the junction box type, ring size, and devices. Devices will have no relation to boxes. 

Oh, and when a receptacle or light switch is selected for the device, the ability to create a power or 

I hope this all makes sense.

[CoreyDaun]

I have not used Assemblies much, but I'm thinking that might be the way to go:

+ You're end-product is comprised of components belonging to multiple Categories. Since a single Family can only belong to a single Category, it may be difficult to control which components are shown on a given View. True, the Nested Families can be of different Categories, but ultimately, their visibility will be dependent on the Host Family's Category. Although this can be managed by creative means, Assemblies would handle this much better.

+ Connectors cannot be "turned off" or removed for certain Family Types, meaning that you'll have all of the Connectors available for every type of connection at all times. For instance, even if a receptacle is not included in the selected Type, there will still be an Electrical Connector available to the user in the Project, which may cause some confusion. Also, the Connectors would have to reside within the Host Family, since Connectors from Nested Families are not available in the Project. With Assemblies, this is not a concern.

+ Generic Annotations from Nested Families do NOT display in the Project, meaning that any such symbols residing in the components (or nested Families) will not display. You would have to create a single Generic Annotation family to properly display the selection of components included in the Type, or at least insert each Generic Annotation into the Host Family and manage their spacing and display via parametric control. With Assemblies, this is not a concern.

+ If you need to create a new Type, it will get very arduous if you keep having to make adjustments to your Family to accommodate the new Types. You will have to make the Family very flexible and anticipate what options may be needed later on. On the other hand, Assemblies are very easily changed and customized. In fact, if you were to simply make a change to an instance of a Family, Revit automatically creates a new Assembly for it. Very easy.

- Unlike a Family, I do not believe an Assembly can be easily transferred from one Project to another. All of the Assemblies (for each "Type") would have to be reconstructed in each Project. But as I stated, I have not done a lot with Assemblies, so maybe I am wrong here.

- If you intend to have Instance-based options that a user needs to be able to change on a case-by-case basis, Assemblies will be a hindrance. Since each instance of an Assembly is identical, a separate Assembly is required for every single possible combination of options. However, as mentioned above, if such a change is made to an instance of an Assembly, Revit automatically creates a new Assembly for it.

There may very well be more pros and cons, but I've covered what I think are the major points, and I think this response is long-winded enough already!