In previous releases of Autodesk Revit you have to add your own hidden detail into family files or use Show Hidden lines and these are then shown in the relevant views.
However, there are issues with this method. Consider the image below showing the structural framing on a roof plan. Notice that the raking steels do not show the hidden detail of the web because they are not 90 degrees (Normal) to the view!
A quick fix for this in Revit 2015 is to use the new feature of Show Hidden Lines which is found in the Properties Palette for views such as plans, elevations, sections etc. 
In the below example I have set this feature to all so all hidden detail is shown. Note that you may have to change your View range settings to allow Revit to show hidden detail of objects outside of this range.
The new Show Hidden Lines command has the following options:
LawrenceH
Autodesk Revit Structure 