You can change dimensions on the drawing sheet to change existing elements. Driving dimensions have relationships that allow you to maintain characteristics such as the size, orientation, and position of elements. When you place a driving dimension on, or between elements, you can change the element size by editing their dimensional values—you do not have to delete or redraw elements at different sizes.
For example, dimensioning the radius of an arc shows its size. Editing the value of the radius dimension changes the size of the arc.
To create dimensional relationships, select a dimension command and click the elements, and key points you want to relate.
To generate driving dimensions, you must set Maintain Relationships on the Tools menu before creating your dimension.