Relative Line Polar Command makes the angle of Polar to last segment 0 so it saves you time in calculating angles. There is an option you can use to change the direction of the angles from counter clockwise to clockwise direction and back again with just a push of a button.

Clicking on the command RLP sets the Relative Polar angle to 0 (Zero).

The installer that ran when downloaded this plug-in from Autodesk App Store has already installed the plug-in. You may need to restart the Autodesk product to activate the plug-in. To uninstall this plug-in, click Control Panel > Programs > Programs and Features (Windows 7/8/8.1) or Control Panel > Add or Remove Programs (Windows XP), and uninstall as you would any other application from your system.

If you have a draw a drawing as shown in the screenshot this command would be suitable to use.