The framework (skeleton) is comprised of reference planes and parameters in which you later create the family geometry.
It also defines the origin (insertion point) of elements that you create with the family.
To create the framework, you begin by defining the family origin. You then build the framework with elements called reference planes and reference lines. Next you define family parameters. The parameters that you define at this stage usually control the size (length, width, height) of the element, and let you add family types.
A view of a family framework
When the framework is complete, you test it by changing the parameter values and ensuring that the reference planes resize. By creating solid frameworks from the information that you gather in your planning stage before you create the family geometry, you ensure the stability of the families that you create.