When you override the value of a driven dimension by editing the dimensional value, the dimension becomes not-to-scale. For example, if you override the dimensional value that is 15 millimeters (A) to be 30 millimeters, the actual size of the line that you see would still be 15 millimeters (B).
Select a driven dimension.
On the command bar, type a new value in the Value box.
Tip:
You can show which dimensions are not-to-scale by using the View→Styles→Style command. This option places a wavy or straight line under dimensional values that are not-to-scale.
To change the dimensional value back to the value of the element it actually measures, delete all the characters from the Value box on the command bar.
You can also hide the dimensional value for a dimension by setting the Dimension Type option to Blank.