I've got a few models exported from Revit MEP 2014 to Navisworks 2015. When I attempt to override the color of a piping system only the fittings (elbows, tees, etc) change color. The pipes remain a dark gray (as indicated in the attached image). Note that the short piece of vertical piping is selected, shows that it's color is red, however, after it's deselected it remains dark gray. There is no insulation on these pipes so it's not that. Any thoughts? Suggestions??