By Justin Doughty
A recent Revit support call triggered my investigation into nested symbols and their visibility/display in families hosted in different ways. I thought I would document this in the details below, and make some suggestions along the way.
The main cause of visibility problems with symbols, relates to the following message when we look at symbols nested in families:
Generally this means the symbol is only visible in some views, and we might have to think about altering the hosting of the host family to get the nested symbol to display correctly. For example we would switch a face hosted family to wall hosted if we wanted a symbol to appear on a wall.
However some families categories, such as Electrical Fixtures, give us a tick box that lets us keep the symbol annotation orientation:
For face based families this means even if the family is hosted vertically on the wall, the symbol will still show:
Great! But what if don’t want to alter the hosting of our family or switch the category to electrical fixtures? We have a face based family and want to show a symbol no matter what the hosting. After a bit of experimenting and testing there is a way, using even more nesting.
In this example, I have taken something simple, a 3D exit sign family, that is face hosted, with a 2D arrow symbol nested into it.
By default we can see at fine detail level, we have the 3D families showing (one on the floor one on the wall): 
Switch this to Coarse detail level, and we only get the 2D symbol on the floor (as the floor is the face parallel to creation):
To make this symbol appear correctly on the wall, we need to create a middle/intermediate face hosted family that is shared, to host the symbol. Then load that into the 3D family:
Going back to the project, the end result is the symbol on the wall:
