Documenting a 3D Model - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 266

Adjusting views
To adjust what we see in each viewport, we must go inside, that is, we access model
space by maintaining the layout configuration. This intermediate state is called float-
ing model space. Some visual changes occur: the cursor appears only inside the
active viewport, elsewhere is represented by an arrow; the active viewport boundary
is thickened, and the triangular coordinate system icon disappears. To access this
state, there are three main options:
• Double-click inside the viewport, this is the easiest and recommended
method
• Apply the MSPACE command, this command (alias MS ) activates the last
accessed viewport; if no accesses occur, it activates the last viewport cre-
ated