Design variables (X-Axis).
Design
Variables 
. Select the design variable that you
want to plot.
Y-Axis.
Objective
. Click this option if you want to plot the selected design
variable versus the objective function.Constraint
. Click this option if you want to plot the selected design
variable versus a constraint. If your study has more than one constraint,
select the desired one from the menu.
Normalized to initial value. Select to plot the selected quantity (the objective function or a constraint) normalized to its initial value.