When drawing Civil 3D Pipes in Section Views or when displaying crossing Pipes in Profile Views you may find that the Pipes do not look very smooth. In fact they may look like the example below that appears to be drawn with just a few straight lines.
If you want to display smooth, more rounded, Pipes you can control this with the FACETDEV system variable. FACETDEV defines the maximum distance from the chord to the arc when drawing Pipes in Section Views and Profile Views. So just set this variable to a smaller number and you will have smoother Pipes.