In an isometric drawing, vertical lines are drawn straight up the screen, and the horizontal lines in the width and depth planes are shown at 30 degrees to the horizontal. When drawn under these guidelines, the lines parallel to these three axes are at their true lengths. Lines that are not parallel to these axes will not be of
their true length. (You may work out from this that Perspectives Pro is a bit of a misnomer – it should really be Isometrics Pro, but that’s marketing for you.)