In Vasari, each element you place in a drawing is an instance of a family type. Elements have 2 sets of properties that control their appearance and behavior: type properties and instance properties.
The same set of type properties is common to all elements in a family, and each property has the same value for all instances of a particular family type.
For example, all elements that belong to the L-shaped Building family have a Width property, but its value varies according to family type. Thus every instance of the 60” x 30” family type within the L-shaped Building family has a Width value of 5’, while every instance of the 72” x 36” family type has a Width value of 6’.
Changing the value of a type property affects all current and future instances of that family type.
A common set of instance properties also applies to all elements that belong to a particular family type, but the values of these properties may vary according to the location of an element in a building or project.
Changing the value of an instance property affects only the elements in your selection set, or the element that you are about to place. For example, if you select a form, and change one of its instance property values on the Properties palette, only that form is affected. If you select a tool for placing forms, and change one of its instance property values, the new value applies to all forms you place with that tool.