A Revit family is a reusable, parametric building component that combines 3D geometry with embedded data — doors, windows, furniture, columns, equipment, or any other element you place in a Revit project. Every single element in Revit belongs to a family, which is why families are called the building blocks of BIM: instead of drawing each object from scratch, you place intelligent components that know their own dimensions, materials, and behavior — and update everywhere at once when a parameter changes.
If you’re new to the software itself, start with what Revit is and what it’s for — this guide focuses on the concept that everything inside Revit is built on. Below: the family hierarchy, the three kinds of families, how parameters work, the file formats involved, and why families beat CAD blocks at their own game.
The Revit Hierarchy: Category → Family → Type → Instance
Everything in a Revit model is organized in four levels, and understanding them is understanding Revit. Let’s trace one real example — an office chair — through all four:
- Category — the broadest bucket, predefined by Revit and not editable: Furniture, Doors, Walls, Lighting Fixtures. Our chair lives in Furniture. Categories control high-level behavior: visibility settings, tagging, and which schedules an element can appear in.
- Family — a group of elements with shared geometry and behavior: the Chair – Desk (5) family. Think of the family as the mold — it defines what a desk chair is (a seat, a back, a five-star base) without fixing every dimension.
- Type — a specific variation of the family with concrete parameter values. Our Chair – Desk (5) family contains a Chair-Task type and a Chair-Task Red type — same mold, different parameter values. Types are what you pick in the Type Selector.
- Instance — each individual element actually placed in the model. Place four chairs around a conference table and you have four instances of the Chair-Task type, each one selectable, taggable, and countable on its own.
You can see this hierarchy live in any project: open the Project Browser and expand the Families branch. Every loaded family appears under its category, with its types nested inside.
The 3 Kinds of Revit Families
All families follow the hierarchy above, but they come in three distinct kinds — and knowing which is which saves real confusion:
System families
Built into Revit itself: walls, floors, roofs, ceilings, stairs, ducts, pipes — the elements that get constructed on site rather than delivered as products. System families cannot be created, deleted, or saved as external files; you work with them by duplicating and modifying their types. Curtain walls are a system family too — one flexible enough that making a curtain wall in Revit deserves its own guide.
Loadable families
External .rfa files that you load into a project: furniture, doors, windows, fixtures, equipment — anything manufactured and installed. This is the kind you’ll work with most, the kind you can download, share, and build a library around, and the kind this entire site is dedicated to. Loadable families are also called component families.
In-place families
Modeled directly inside a specific project for one-off geometry that will never be reused — a sculptural reception desk, a custom concrete form. They do the job, but use them sparingly: in-place families can’t be reused in other projects and are heavier on model performance than a proper loadable family.
| Kind | Where it lives | How you get it | Typical use |
|---|---|---|---|
| System | Inside Revit / the template | Duplicate an existing type | Walls, floors, roofs, curtain walls |
| Loadable | External .rfa file | Download or create, then load | Furniture, doors, windows, equipment |
| In-place | Inside one project only | Model it in the project | Unique, unrepeatable geometry |
Type Parameters vs Instance Parameters
Parameters are the “data” half of a family, and they come in two flavors that trip up every beginner:
Type parameters belong to the type — change one and every instance of that type updates at once, across the whole project. The seat width of the Chair-Task type, the material of its upholstery, the glazing buildup of a window type: edit it once in Type Properties and all placed copies follow. Think of type parameters as the manufacturer’s catalog sheet.
Instance parameters belong to one placed element only: its level, its height offset, its individual mark number, its phase. Change them and only the selected element moves. Think of instance parameters as this specific unit on site.
This distinction is what makes schedules work. A furniture schedule groups elements by family and type and counts the instances — load one conference table family with shared nested chairs, and the schedule reports each type with its count automatically:
One loaded table family with shared nested chairs, and the schedule reports every family and type with its count — seven elements from a single load. That’s the hierarchy doing its job.
Revit Family Files: .rfa, .rft, and .rvt
Three extensions cover the family world:
- .rfa — a loadable family file. This is what you download from a library and load into projects.
- .rft — a family template, the starting point for creating a new family in the Family Editor. Each category has its own template (door, window, furniture…) with the right behavior pre-wired.
- .rvt — a project file. Once loaded, families live inside the .rvt — you can delete the original .rfa and the project keeps working.
Some .rfa files ship with a companion .txt — a type catalog that lets you pick which types to load, which we cover in loading a family with a type catalog. And one compatibility rule to tattoo somewhere: Revit files only move forward — a family saved in a newer version won’t open in an older one. Version troubleshooting is covered in our family loading guide.
Revit Families vs CAD Blocks
If you come from AutoCAD, the closest thing to a family is a block — and the comparison shows exactly why the industry moved to BIM. A CAD block is dumb geometry: lines and arcs grouped under a name. A Revit family is geometry plus data plus behavior. A door as a block is a drawing of a door. A door as a family knows its clear width, its fire rating, its material, and its hardware set; it cuts its own opening in the wall that hosts it, appears in the door schedule with the rest of the project, takes a door tag, and updates every plan, section, and elevation the moment you change its type. The block represents the door — the family is the door, as far as the model is concerned.
Where Do Revit Families Come From?
Four sources, in the order most people meet them:
- Autodesk’s cloud library — the stock content that used to install locally now lives online, accessed via Load Autodesk Family. Generic but reliable.
- Manufacturer BIM objects — real products modeled by (or for) their manufacturers, with catalog-accurate data.
- Third-party libraries — curated collections like ours: browse the full Revit family library or jump into furniture, doors, and curtain walls, all free and organized by Revit version.
- Your own creations — built in the Family Editor from an .rft template, with parametric dimensions and custom parameters. Creating families well is a craft of its own, and one we’ll cover in a dedicated guide.
However you get the .rfa, bringing it into a project takes thirty seconds — here’s how to load a Revit family, every method included.
Frequently Asked Questions
What’s the difference between a family and a type in Revit?
The family is the mold — shared geometry and behavior. A type is one concrete variation of that mold, with specific parameter values. One family contains one or more types: the Chair – Desk (5) family holds both the Chair-Task and Chair-Task Red types.
Can you edit system families in Revit?
You can’t create, delete, or export them, but you can freely duplicate and modify their types — wall assemblies, floor buildups, mullion profiles. Duplicating a type before editing is the standard practice so the original stays intact.
What file format is a Revit family?
Loadable families are .rfa files. System families have no file of their own — they live inside the project or template. Family templates for creating new content use .rft.
Are Revit families free?
Many are. Autodesk’s cloud library is free with the software, manufacturers publish free BIM objects of their products, and libraries like ours offer thousands of free .rfa and .rvt downloads organized by category and Revit version — start at the family library.
How do I create my own Revit family?
Open Revit, choose File > New > Family, and pick the .rft template matching your category. Model the geometry, add parametric dimensions, and load it into a project to test. It’s a deep topic — a full step-by-step guide is on our roadmap.
Start Using Families
So — what is a Revit family? The unit everything in Revit is made of: a parametric component that carries geometry, data, and behavior through the whole hierarchy, from category down to the instance sitting in your floor plan. Master the family-type-instance logic and the rest of Revit stops fighting you. The fastest way to build that intuition is hands-on: grab something from our free Revit family library, load it into a project, and watch the hierarchy work.
