To activate the Rulers in ArchiCAD 13, hit the Ruler icon at the top of your screen. From the Rulers you can get a visual location of your cursor and drag out Guide Lines.
Ruler is a new editing aid in ArchiCAD 13 that gives instant, dynamic feedback on cursor’s vertical and horizontal position. If you want to show/hide the Ruler go to View>Ruler. You can also hide a ruler by right-clicking it as shown below: Note: This feature can be used in every ArchiCAD window, except the 3D