Ortho
The ortho guide is a very simple and useful tool. With Ortho on, points can only be specified at 90° angles. Also, Ortho allows you to indicate a direction with the mouse and enter a distance with the keyboard. Ortho will automatically correct the angle to either 0°, 90°, 180° or 270°, and it will use the distance you specified with the keyboard, not the mouse. This can help you to quickly enter dimensions in to Draftsight.
To temporarily enable Ortho, hold the shift key while you draw.