A Quick Breakdown of Nested and Shared Families

Using nested and shared families is quite a simple process, however, for new Revit users or even just users that haven’t explored the power of this process, it can initially be a little daunting. Once you understand these features of Revit you will wonder how you ever lived without them, and not only that, the possibility of endless customisations of many of the RevitHQ families’ opens up to you.

To begin with, let’s break down the terms nested and shared, how they are different, and why you should utilize these powerful features.

Nested Families: A term used for a family that is 'nested' in another family. When the host family is inserted into a project, it will be the only family that is loaded in.

Shared Families. A term used for a family has had the 'shared' tickbox enabled in its properties. When shared families are nested in a host family, and that host family is inserted into a project, both the host family and the nested family will be visible in the project browser.

Nested Families

To reiterate, nested families are families that have been ‘nested’ in other families, exactly like it sounds. Any good family creator will utilise nested families. They greatly simplify the family creation process by compartmentalising different elements of the model. An example of this could be a table, the legs of the table could be created in one family, the tabletop in another family, and the two could then be combined in a third family.
While it would be possible to model both of these nested elements in the same family. Using this method would mean:

• All the constraints, reference planes and equations that make the table base won’t interfere with the tabletop, and vice versa.
  
• Any updates to the tabletop or base can be made without the fear of affecting other modelled elements.
• Anyone unfamiliar with the model can easily perform error analysis with significantly more ease.

Furthermore, any parameter created in these nested families, whether they be instance-based or type-based, can then be linked to the parameters in the hosting family. Thereby giving you the ability to either use their constraints in equations or have their size influence other nested families.

To do this, insert your nested family into your host family and navigate to the type or instance property you wish to link.

Linking can be achieved by selecting the small grey box next to parameter, and clicking this box will take you through the standard process of creating a new parameter. After this is done, the equal symbol will appear in the grey box as shown in the example below.

Now that the link has been made the nested family parameter is being controlled by the new parameter ​in your host family.

​Head to the family types dialogue box to find your newly created parameter and begin adding some equations. ​Or simply insert your host family into your project and begin flexing the linked parameter.

Shared Families

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Shared families are where things get a little more interesting and a little more confusing. In the previous example, we showed a nested table top and base scenario, changing these to be nested and shared is simply a matter of checking the ‘Shared’ tick box found in the ‘Family Category and Parameters’ dialogue, shown right.

But it can also be found in the properties bar when no objects are selected.

Any family can be made into a shared family, but it will have a number of effects that are very important to be aware of.

1. To begin with, shared families are what they sound like, shared. By making a nested family shared, it will also be loaded into you project along with the host family, visible in your project browser like any other family. It essentially becomes a family that can be adjusted and placed independent of its host if needed, while simultaneously existing in the host family.
2. Any updates to the nested and shared family can be done straight from the project by editing the family from the project browser, propagating those changes to any instance in you project.
   
3. This nested and shared family can be used in multiple host families, meaning any changes made will update to all host families.
   
4. Nested and shared families can be scheduled independent of their host families.
   
5. Nested and shared families can be selected and tagged in your project, independently of its host family. An example of this would be tagging your door handle and lock in elevation, separate to the door tag. This will even work for nested and shared families of different categories. To do this, use the tab key when hovering the mouse over the family to cycle through its shared components, then select or tag as needed.

​Shared Families Points of Confusion

I made my family shared and loaded it in but how do I change it back to just a standard family?

Be cautious when making a family shared. For a family can be edited, made to be shared, and loaded back into your project or family, but once shared it is more difficult to un-share. The 'shared' tick box is easy enough to deselect, but the problem comes when reloading the family back into the project, as seen in the error shown right.

The reason for this, I believe, is most like due the implications un-sharing a family can have on multiple host families that might be using the same nested and shared family. If you wish to un-share a family, it must be first completely removed from the project or family, and then reloaded in. A pain when you have already used it in multiple locations.

I've made my family shared, loaded it into my host family, but can’t link the type parameters.​

When in the family editor environment and nesting a shared family in a host family, the type properties of the nested families won’t be able to be linked. Only the instance properties of a nested family will be able to be linked. This doesn’t mean that you shouldn’t use type parameters in the nested and shared families; type parameter will still be adjustable in the type settings of the family when inserted into your project. We will cover this in more detail in another post, as it is a great way to compartmentalize large amounts of adjustable parameters, reducing complexity and increasing customization potential.​

Advanced use of Nested and Shared Families

Newly created shared families loaded straight into a project can be swapped into a family that has the same category type of that family already nested and shared in it. This process sounds confusing put to words, but fundamentally it is a quick and easy way to swap in the new custom design of nested and shared family without ever needing to open and edit the host family. An example would be modeling a new table base, loading it into your project and swapping it in using a 'Family Type' parameter of the the host family, all without ever opening family.