Improve 3D Appearance of Pipes and Structures in Civil 3D

When viewing pipes and structures in 3D with the "Realistic" visual style in Civil 3D, rounded shapes may appear faceted rather than smooth. The image below shows an example of a Humes eccentric flanged manhole alongside a circular culvert with three barrels:

To improve the appearance, go to Civil 3D Options, Display tab, and set the Rendered object smoothness value to 0.5 or higher:

Result: