About Families

Families are classes of elements within a category that group elements with a common set of parameters, identical use, and similar graphical representation. Revit contains various predefined families, which you can use in your projects. You can modify these predefined families to suit project requirements. You can also create custom families by using templates for beams, columns, and foundations.

Definition of Families

A family is a collection of objects with similar characteristics. These characteristics are represented by instance and type parameters. Instance parameters are specific to a particular instance of an object in a structural model, but type parameters apply to all objects of a particular type. Different elements within a family may have different values for some or all properties; however, the set of properties is the same. Each element with a different value is a new type within a family. For example, a beam with a specific profile can be of different sizes and all beams of different sizes are new types within the beam family. Similarly, rectangular columns can be considered as one family, though the columns belonging to the family are available in different styles and different sizes within those styles.

The following illustration shows different types of columns belonging to the Structural Columns family.

Component and System Families

There are two types of families, component and system.

Component families, also known as loadable families, are families for which you can specify parameters and graphical representations. The extensive library of component families includes annotation components, 2D detail components, and 3D model components. You can create component families by using family templates or by loading existing component families into a project. You can also modify the existing component families.

A special type of component family is an in-place family, which is specific to the project in which it is created and edited. An example of an in-place family is a tapered column.

System families are families that have a predefined set of parameters and graphical representation. The system family library includes walls, dimensions, roofs, floors, and levels. System families arenot available as external files; therefore, you cannot load or create system families as separate files. However, you can modify the existing system families to suit project requirements or organization standards. You can use a predefined system family to generate new types in that family in a project. For example, although the behavior of a wall is predefined, you can still create different types of walls with different compositions. You can transfer system families between projects.

The following table shows an example of an element, a family, a type, and an instance.

Option	Example
Element	Wall
Family/System family	Basic Wall
Type	Exterior - 12" Concrete
Instance	Actual user-drawn wall in a project

Example of Families

Revit provides controls for how elements are constructed and located in a project using the Family, Type, and Instance Properties dialog boxes. The family properties control the geometry of elements, the type properties control their size, and the instance properties control the location of elements in space.

The following illustrations show a wall instance, different wall families, and a wall family type.