Families are the heart of how Revit works. Almost everything you place in a model — walls, doors, furniture, light fittings — is a family. Understanding the three kinds, and when to use each, is one of the biggest steps from “clicking around in Revit” to actually working efficiently. Here’s a clear, practical introduction.

First, the hierarchy: category → family → type

Revit organizes elements in three levels. A category is the broad class (walls, doors, furniture). A family is a group within that category that shares behavior and parameters (a particular door design). A type is a specific variant of that family (that door at 900 mm vs 1000 mm wide). Get this hierarchy straight and the rest of families makes sense.

The three kinds of families

Three kinds of Revit families System Built-in, not external files Walls, floors, roofs, ceilings Make new types, not new files Loadable External .rfa files Doors, windows, furniture Reusable across projects In-Place Made inside the project One-off custom elements Not saved as separate files

System families

These create the basic elements you’d assemble on site — walls, floors, roofs, ceilings, stairs — plus project settings like levels, grids, and sheets. They’re predefined in Revit, built into the project or template; you don’t load them from external files. You can’t create brand-new system families, but you can (and do) create new types within them — for example, the Wall category includes Basic Wall, Stacked Wall, and Curtain Wall, and you make your own wall types from those.

Loadable families

These are the components you’d usually purchase and install — doors, windows, casework, fixtures, furniture, planting. They live in external .rfa files and are loaded into projects, which makes them highly customizable and reusable across multiple jobs. Because of that flexibility, loadable families are the ones you’ll most often create and modify, using the Family Editor where you define geometry, parameters, and materials. They can also be nested inside one another.

In-place families

These are unique elements modeled directly inside a project — a custom reception desk, a one-off decorative column. They’re created and edited much like loadable families, but they can’t be saved as separate .rfa files for reuse. Use them sparingly and only for genuinely one-off elements; overusing in-place families can slow down large models.

How to create a loadable family (the basic workflow)

  1. Start from a family template. Revit ships with .rft template files that carry the right defaults for each category. Pick the one matching what you’re making (e.g., a furniture or door template).
  2. Build the geometry. In the Family Editor, model the form using extrusions, sweeps, and other solid tools, working against reference planes.
  3. Add parameters. Define the dimensions and properties you want to control (width, height, material). This is what lets one family produce many types.
  4. Create types. Set up the specific variants you’ll use — the same family at different sizes or finishes.
  5. Load into your project. Save the .rfa and load it into your model, then place it. Because it’s an external file, you can reuse it on future projects.

Choosing the right kind

A simple rule: use system families for the building’s basic fabric, loadable families for reusable components, and in-place families only for unique, project-specific elements you’ll never need again. Choosing well keeps your models efficient, accurate, and well-organized — and keeps file sizes and performance under control.

Part of our Revit tutorials series. Next: the top Revit keyboard shortcuts to speed up your workflow.