On the Tools menu, click Show Grid. Display the grid on a 2D view to assist in drawing walls and <null> lines, and to help you to more accurately place windows and shades. The command will also display the grid on the selected 3D view. Displaying a grid on one view will not automatically display it on other views. The grid will be drawn as a series of dotted or solid lines, the default setting will be solid lines. You can change the setting on the Grid dialog to redraw the grid with dotted lines.