When you are working with Revit Families, Symbolic Lines are a fantastic way of showing detail without having the entire model represented.
A small restriction to some family types is the Visibility setting, ‘Show only if Instance is Cut’ which will allow you to have the Symbolic Lines appear only if the family is cut in the view. The option is greyed out in a lot of the family categories, especially Generic Models.
If you need the ability to activate this option, here is the solution.
Change the Category of the Family to a Category where the tick box is available. ‘Casework’ works fine. (It is only temporary, so is doesn’t matter about which Category it is, just one that works).
Now if you select the line and go to the Visibility Settings, the ‘Show only if Instance is cut’ tick box is available.
Once the box is ticked, if you then switch the Category of the Family back to its original Category, the Visibility Option will Grey out again but it will remain ticked.