In simple terms, a Revit family is a collection of elements that share common properties (parameters) and associated graphical representations. This concept is similar to a block in CAD, which consists of numerous graphic elements grouped together. Some people have described a family as a block with specific attributes, but unlike blocks, the properties of a family are far more powerful.
A Revit project is a comprehensive information model that includes everything users need, such as three views, schedules, component data, and more. This information model is built from a combination of multiple family types. The concept of the family is essential in Revit; using it properly can optimize data management and simplify modifications.
Unlike display components in SketchUp or 3ds Max, all elements within Revit are family-based. Each family contains multiple sets of parameters and information. Editing a family does not require programming skills—Revit offers a user-friendly editing function that provides predefined templates. Users can add specific parameters like material, size, and others to the family according to their requirements.
For example, a standard door family might include various width options such as 900mm, 700mm, and 1200mm within a project. Depending on the location, the door’s material, height, and shape may differ. Without predefined parameters, all doors created during drafting would have the same material and size, making it impossible to differentiate their specific functions and uses. In such cases, the information model would serve only as a visual display.
Revit categorizes families into three types:
(1) System Families – These are built-in families inherent to the software, which can only be created and modified within a project (examples include walls, doors, and windows). System families cannot be linked or loaded into a project as external files, nor can they be deleted, created anew, or externally modified. System settings that affect the project environment, such as elevations, grids, drawings, and viewport types, are also considered system families. Although they can’t be loaded into templates or other projects directly, system families can be transferred by copying and pasting.
(2) Loadable Families – Also known as standard component families, these can be created using Revit’s loading function. Users can either create custom components using RFA template files provided by the software or download them from online sources. Unlike system families, loadable families are highly customizable, can be loaded as external files, and can be copied and used across multiple projects. They form the basic units for building family libraries. Examples include annotation graphics, windows, doors, appliances like washing machines, and furniture such as tables and chairs. Loadable families also support nested operations by loading multiple families into the same template, which saves time.
(3) In-Place Families – These are unique graphic elements created specifically for a single project. They cannot be saved separately as RFA files or reused in other projects. Revit generates a family for the in-place element, which contains only a single family type.
All three types share a common feature: they are parameterized. Parametric design is at the heart of Revit. Families are presented as components, and the variety of components is controlled by parameters. Any change made to a component is instantly reflected in all related objects. This ensures that modifications in one view are automatically updated across all other views, including 3D models, in real time.
Must log in before commenting!
Sign Up