Dimension-driven design (DDD) is the process by which elements are drawn with respect to previously determined dimensions, and/or relationships between dimensions.

Taking a very simple case, for example, you may have a rectangular element in which you want the width always to be half the length. You can create a dimension-driven cell, with this constraint defined. When you place the cell, you need only define the length and the width is determined from the constraint formula. Similarly, when you use the DDD tools to modify the length, the width also is modified to maintain the relationship.