Variable Driven Modeling and Constraints
The Variable Driven Modeling (VDM) tools let you assign variables or equations to the parameters of solids and features contained in your models. For example, if a slab always has its width and height as percentages of its length, you could set equations for these such that any changes you made to the length would automatically correct the width and height dimensions to maintain the relationship. Variables may contain simple values or equations that define a value. Equations also may include previously defined variables.
Many of the settings for features have an equation icon, signifying that you can assign a variable, or an equation, to the particular setting.
Working in conjunction with the variable driven modeling tools, the Constrain Feature tool lets you constrain a feature of a solid. That is you can constrain, or fix, a feature so that it remains in the same relative position on a solid irrespective of how the underlying solid's dimensions are modified. For example, you could constrain a hole to always be 25 mm from a slab's edges. Settings for constraints also may include variables or equations.