Adding billboards
Billboards put images into the 3D scene — a field photograph beside the outcrop it was taken at, a map, a panel of text explaining what a visitor is looking at.
Add one from the Annotations ribbon tab (Add a billboard), or by dragging an image onto the model as the video shows.
A billboard is not limited to one image. Give it several and it becomes a small presentation you can step through, which is what makes billboards useful for a virtual field trip as well as for annotating your own work. Video works too, with playback controls on the board's header strip.
Full detail — the header bar, the transport controls, sizing, and how billboards behave in a presentation — is in Using Billboards; the Data Tree commands are listed in Billboards.