What made AD think that if I used the 3d section box tool (bx) that I would not also want to section off whatever else was attached to my model. The whole excercise is a bit pointless if you end up with a marker pointing to a pixel on an otherwise blank screen. To replicate this, think of a large industrial plant building (ARC) and you want to isolate your view to a single one inch valve (Systems).
I propose to enhance the 3d section to cover whatever Revit would otherwise show in its 3d view window.