Surfaces that are not visible are clues to bad objects - bad trims, bad joins etc. They are invisible because Rhino can’t figure out how to mesh them to make them visible. Does rhino say your object is valid? (Check command)
If you explode the object, the surface will probably magically become visible again. Once exploded, if you run RebuildEdges on all surfaces and then Join, you will probably see a bunch of naked edges where the tolerances are out.
–Mitch