Roof disappearing and walls are transparent in referenced file

[SharonP]

I am working on a project with 6 houses, which I have set up in separate files, and for some perspectives I have referenced those files into one separate file.  In each of the 6 individual files I can view a perfect perspective with hatched walls and roof (hidden line view) but as soon as I look at a 3d view in the referenced file, the roofs all disappear and the walls are transparent.  This happens as soon as I use the flyover tool.  If I have a look at the front view for example then I have solid walls with no hatch showing (in hidden line) and no roof.

 

Does anyone have any clue as to what is going on?  I have wasted about 4 hours so far trying to work this out.   I have checked and rechecked all the class and layer visibilities, and this is happening even with all of them set to visible.  Even looking at the 6 houses in top view I can see all of the walls instead of the rendered roofs.

 

I have the "use current documents class visibilities" button ticked in each referenced viewport.

 

Anyone got any ideas of what I am missing?

 

I woke up this morning (in NZ)  hoping that it had magically fixed itself, but no luck 😕

 

Sharon