Select one or more Y columns or a range of data from at least one Y column. If there is an associated X column, X column supplies X values; otherwise, sampling interval of the Y column or row number is used.
Select required data.
From the menu, select Plot > Basic 2D : Vertical Drop Line.
Click the Vertical Drop Line button on the 2D Graphs toolbar.
DROPLINE.OTP (installed to the Origin program folder).
Drop lines can be turned on or off from the Drop Lines tab in the Plot Details dialog box.