Select at least one Y column (or a range from at least one Y column). Ideally, select at least two Y columns (or a range of at least two Y columns). If there is an associated X column, X column supplies X values; otherwise, sampling interval of the Y column or row number is used.
From the menu, choose Plot> 3D: Walls: 3D Walls.
Click the 3D Walls button on the 3D and Contour Graphs toolbar.
(Installed to the Origin program folder)