There appears to be an issue in CC2017 and CC2015 with the menu item 3D Show/Hide Polygons.
Selecting an area and hiding the polygons works correctly - however Reveal All - remains greyed out in the menu so the polygons cannot be unhidden.
I checked in CS6 and this feature works as expected (i.e. once polygons are hidden then Reveal All becomes available to unhide them) .