I am trying to help a coworker who needs to show a typical ventilation ductwork layout with three different terminal devices serving the system. Just to paint a picture one system will be served by VAV, one on a terminal coil, and the final option would be a some type of valving.

I suggested using design options to show the typical ductwork, air terminals in the main model. Then create the three design options to show the different terminal devices. The problem I have is how can he annotate these 3D views with just descriptive text, e.g. pointing to the terminal coil and noting "TERMINAL COIL".