Marking up CAD Models
In the 3D model markup mode launched with the Markup button on the Basic Markup or Standard Markup toolbar, an end user can annotate a 3D CAD model with arbitrary lines, highlighted areas, and labels.
A 3D model view with markup items should be explicitly saved before switching to the model viewing mode because all current markups are not saved and will be lost during this switching: the viewing 3D scene will not have them.