of the drawing displayed on the screen 25 one of the adjoining walls bc in the example is then drawn on the screen 25 the operator then positions the measuring units 50 60 at the junction of the first and second walls corner b and directs the laser to a target adjacent corner c to obtain an accurate reading for the length of the second wall bc and the direction of wall bc relative to the first reference wall ab in practice this direction is usually close to 90 degrees the relative distance and angle are transmitted to the computer and adjustments made to the sketched wall in proportion to the display scale next a third wall cd adjoining the second wall bc is drawn and the operator then directs the measuring units 50 60 from the corner c to the far corner d to obtain an accurate reading for the relative length and direction of the wall cd the process is repeated around the entire perimeter of the house setting the length with the distance measuring unit 50 and the direction with the angle measuring unit 60 referring now to fig5 through fig8 the use of the instrument for interior dimensions is.