To Create a New Expression while applying a 2D Dimensional Constraint

Select the desired Dimensional constraint tool (Home > Constraints > Dimensional).

Select the profile(s) or segments to constrain.

Enter a data point.

The following drop-down appears:

Select New Expression.

The Expression Builder dialog opens.

Create the desired expression.

Select OK to accept.

The newly created expression will be applied to the variable and will display in the Variables Dialog.