If Revit projects are buildings made of data, then Families are the vocabulary from which that data is assembled. Every element you place in a Revit model — every wall, door, window, structural column, light fitting, plumbing fixture, and piece of furniture — is defined by a Family. The ability to create, customise, and manage Families is one of the most important advanced skills in Revit, separating users who are dependent on the default content library from those who can build models that precisely represent their actual design intent. This guide explains the Revit family system and takes you through the process of creating custom loadable families.
The Three Types of Revit Families
Revit uses three distinct family types, each suited to different modelling scenarios:
System Families
System families define elements that are integral to Revit’s structure: walls, floors, roofs, ceilings, staircases, railings, MEP ductwork, and pipes. They cannot be loaded from external files or saved independently — they exist within the project file. You create new types within a system family by duplicating and modifying an existing type (for example, duplicating a wall type to create a new wall specification).
Loadable Families
Loadable families are the most versatile and widely used category. They are stored as separate RFA (Revit Family) files and loaded into projects as needed. All doors, windows, furniture, structural columns, equipment, and fixtures are loadable families. You can download manufacturer BIM content (typically in RFA format), use the Revit content library, or — critically — create your own in the Family Editor.
In-Place Families
In-place families are custom elements created directly within a project for unique, non-repeating elements. A bespoke reception desk designed for a specific location, or a sculptural roof canopy that only occurs once, might be modelled as an in-place family. They are less efficient than loadable families (they cannot be reused in other projects) and should be used sparingly.
Anatomy of a Loadable Family
Every loadable family consists of:
- A Category — the Revit category to which the family belongs (Doors, Windows, Furniture, Structural Columns, Lighting Fixtures, etc.). The category determines how the family behaves, what system connectors it can have, and how it appears in schedules.
- Reference Planes — the geometric skeleton of the family. Reference planes define the critical dimensions and provide the anchor points to which geometry is locked.
- Geometry — solid extrusions, blends, revolves, sweeps, or symbolic lines that represent the element visually.
- Parameters — the variables that control dimensions, materials, and other properties. Parameters can be Type parameters (same value for all instances of a type) or Instance parameters (individually adjustable for each placed instance).
- Family Types — specific configurations of parameter values. A door family might have types for 762mm, 838mm, and 915mm leaf widths, each with the correct frame dimensions automatically calculated.
Opening the Family Editor
The Family Editor is a separate Revit environment dedicated to family creation. Open it by:
- Creating a new family: Go to File > New > Family and select an appropriate family template (RFT file). Choose the template that matches your element category — Metric Door.rft for a door, Metric Window.rft for a window, Metric Generic Model.rft for a general component.
- Editing an existing family: In a project, select a placed element and click Edit Family in the Ribbon. The family opens in the Family Editor.
The Family Editor interface is similar to a project environment but simplified — you have plan, elevation, and 3D views available, a Ribbon with family-specific tools, and the Properties Palette for parameter editing.
Creating a Custom Loadable Family: Step-by-Step
As an example, we will create a simple parametric louvre panel — a common architectural feature that does not exist in the standard Revit content library.
1. Choose the Right Template
Create a new family using the Metric Generic Model.rft template. For a wall-mounted panel, consider using Metric Generic Model face based.rft, which automatically orients the component to the face of a host wall.
2. Set Up Reference Planes
In the plan view and front elevation, draw reference planes to define the overall dimensions of the panel. Draw a vertical reference plane at the left and right edges (the panel width) and horizontal reference planes at the top and bottom (the panel height). Draw a third plane for the panel depth.
Label the reference planes by clicking on each plane and entering a name in the Properties Palette (e.g., “Left”, “Right”, “Top”, “Bottom”). These labels make the planes easier to reference when adding constraints.
3. Add Parameters
Go to Create > Properties > Family Types to open the Family Types dialog. Click Add Parameter to create parameters for:
- Panel Width — Type parameter, Length, default value 1200mm
- Panel Height — Type parameter, Length, default value 2100mm
- Panel Depth — Type parameter, Length, default value 100mm
- Louvre Spacing — Type parameter, Length, default value 150mm
- Louvre Blade Thickness — Type parameter, Length, default value 12mm
- Panel Material — Type parameter, Material
4. Constrain Reference Planes to Parameters
In the elevation view, add a dimension between the left and right reference planes. Click the dimension, then in the Options Bar click the small label dropdown and select the Panel Width parameter. The dimension is now driven by the parameter — changing the parameter value will move the reference planes accordingly.
Repeat this for Panel Height and Panel Depth dimensions. All reference planes are now fully parametric.
5. Create the Geometry
Select Create > Forms > Extrusion. Draw the cross-section of a single louvre blade in the side elevation — a thin horizontal rectangle at the angle you want (typically 30-45° to the vertical). Constrain the depth of the blade to the Panel Depth reference plane.
For the repeating louvre blades, use an Array. Select the extrusion, then go to Modify > Array. Set the spacing to be driven by the Louvre Spacing parameter. The number of blades should be calculated from the panel height divided by the spacing — enter this as a formula in the Family Types dialog: Number of Blades = Panel Height / Louvre Spacing.
6. Assign Materials
Select the louvre blade geometry, go to the Properties Palette, and click on the Material field. Set it to associate with the Panel Material parameter. Now users can change the panel material from aluminium to timber to steel simply by changing the instance parameter when placing the family in a project.
7. Define Family Types
In the Family Types dialog, create several standard sizes — 600 x 2100mm, 900 x 2100mm, 1200 x 2100mm — as named types. Each type stores a specific set of parameter values. Users can select from these predefined sizes when inserting the family, or adjust dimensions as instance parameters.
8. Load into Project
When the family is complete, click Load into Project in the Ribbon. The family is available immediately in the project’s family browser. Place instances, assign types, adjust instance parameters, and the parametric model updates instantly.
Best Practices for Family Creation
- Always use the correct family template — the template sets the category and connection behaviour.
- Lock all geometry to reference planes — geometry that floats free of reference planes will not resize parametrically.
- Test all parameters extensively — try extreme values (very small and very large) to ensure the family does not break at unusual sizes.
- Keep geometry minimal — overly detailed families slow down model performance. Represent fine detail with 2D symbolic lines for fine and medium detail levels, switching to full 3D only at Fine.
- Use nested families for repeating sub-components — nest simpler families (e.g., a bolt head) within a larger family (a connection plate) rather than modelling every detail in one complex geometry.
Build the Content Library Your Projects Deserve
Custom Revit families are a long-term investment in your practice’s modelling capability. A well-built library of parametric components — custom wall types, bespoke joinery families, project-specific structural sections — reduces modelling time on every subsequent project and ensures your models accurately represent your designs rather than Autodesk’s defaults.
Revit 2026 is available from GetRenewedTech at €46.99 for one year of access on Windows — including the full Family Editor and all the tools needed to build a comprehensive practice content library.
