Tips for Nested Families
In this article we will look at creating an Autodesk® Revit® family. Along the way some suggestions will be made about nesting families and organizing your content.
Housekeeping
There are a few things you need to consider when creating content that will save a lot of questions and time in the long run. I will not go into a lot of detail—just give you things to think about to help guide you when creating and organizing your content.
- File Naming. When naming your families, you must consider a name, a location and a way to differentiate your content from the out-of-the-box content provided with Revit. Also, keep in mind that you may schedule the Family Name.
- Ask yourself the question, “How often will this content be used?” If the answer is more than 75 percent of your projects, then you also may want to load the content into your project start-up template.
- Limit the number of views you are placing your dimensional parameters when in the family editor. If someone needs to adjust your family, or just go into the family to understand the functionality, it will be easier to navigate.
- Should your parameters be instant, type, and/or shared? Keep in mind shared parameters can be scheduled and offer consistency when naming parameters within families.
- Name your reference planes. This is a good habit to develop. Even if there are only a few, the habit of naming them will give you a better understanding of the family.
- Always apply your constraints to reference planes, reference lines, and formulas. Then constrain your geometry to the reference planes and reference lines.
- Always test your family by adjusting your parameters to make sure it works.
- Create a screen snapshot showing the adjustable parameters, and call it the same name as your family. A new user can open the image file to better understand its functionality and what the parameters control without going into the family editor.
- Does the family require a type catalog? If this is a family that has five or fewer types, you may want to avoid going through the effort of making a type catalog.
- Create new family templates. There will be a lot of repetitive tasks that you do with every family you create. If you can capture this and save it to a new family template, you will save a lot of time as you create additional content.
- Develop a standard method of pushing new content and communicating its availability to the team.
Those tips just scratch the surface and I hope to point out more during this tutorial of creating a family for the main support in a pre-engineered building.
Figure 1: Pre-engineered building frame
Nested Families
Do not try to put everything in a single family if it makes sense to break it down into simpler parts. For example: With this family, I want to end up having the ability to array the frame to layout the overall length of my pre-engineered building. For this family, it makes sense to have three families.
The first will be a profile that is adjustable to control the flange size and thickness. The profile will be a nested family in the main frame family. Then the main frame family will be nested in the final family to use in the array. Sure, all of this can be done in a single family with the same result, but the more you try and accomplish in a single family, the more difficult it will be to manage and adjust.
Figure 2: Profile family
Building the Family
Figure 3 shows the completed main frame family for the pre-engineered building. The profile family is nested in this family and is used to create the six separate sweeps. Note “A” in the figure points to one of the six sweeps generated. When you nest a family that has associated parameters you must make parameters in the current family to carry through the functionality of the nested family.
Figure 3: Main framing component for pre-engineered building
The profile that is nested may have other uses when nested in other families. For example, this simple rectangular profile may be used as a reveal in a wall system family. With that in mind you may want to have a directory to just store profiles, then name them in an obvious way so others can leverage the work already done. When families can be reused you want to name the parameters generically. In this profile the two parameters are Profile Width and Profile Height. However, when this profile is nested into our frame family we can link the generic parameters to something more descriptive.
Figure 4: Linking the profile parameters to something more descriptive in the host family
We can use this frame family to create the main framing in a pre-engineered building. However, this is a repeatable component and it would be nice to take it one step further by defining the overall length of our building and the distance between the framing components. To do this I will nest this family into a new family. The new family will only have a couple of new parameters to control the array. The rest of the parameters will be created to carry all the functionality of the nested families forward.
Figure 5: New parameters needed to support the array
Figure 6: Array using the new parameters
Figure 6 shows the new parameters being applied in the new family. These new parameters are all instance parameters so there can be unique instances if needed.
Figure 7: The resulting 3D view
Summary
This was a basic family which could save a lot of time when laying out a pre-engineered building. Design your families to save time. Develop your family with a process in mind, develop good habits, and stay organized. Revit is all about the content—the better, more complete content you create will directly affect time and bottom line costs on a project.
