Well I just figured out that I can do a 3D plot by adjusting my 'shaded vieport options' on the plot window, but it would be very helpful if it were possible to plot in a hidden mode(that will hide the architecture behind the duct & not show the dashed lines of the hidden edges of the duct) & see the duct sizes directly on the sides or top of the duct. I have used other software packages, such as CAD-PIPE, that can do this easily.