Ruler
Levels found: 
Drop Down: View
Icon: 
Key Command-1: R
A. Click and drag to set (0,0) location.
(Figure Ref-R-1)
B. Horizontal measurements (Figure Ref-R-1)
C. Vertical measurements (Figure Ref-R-1)
Description:
The “Ruler” function is an electronic measuring tool that
extends across the top and down the left side of the
also aid in the visual representation of the design scale.
Right click on the ruler to set the ruler measurements to
Metric or Inches. (Figure Ref-R-2)