You can use both 2- and 3-dimensional geometry to create families. Create solid geometric shapes to represent the element that the family is intended to create. Use 2D linework to add detail to solid geometry in certain views or to create a symbolic plan representation of an element.
As you create the family geometry, you can specify the visibility, material, and an optional subcategory of the geometry. These settings determine how and when the specific geometric components of the family display.
To ensure the stability of each parametric family, build the family geometry incrementally, testing (flexing) the parametric relationships in each increment.