Documenting a 3D Model - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 274

The round viewport should also have the same visual style and a Top
view. Double-click outside to return to paper space.
8. Let's specify scales for all viewports. Select all rectangular viewports and,
on the scales list (status bar), select 1:1 . To the circular viewport, apply
2:1 :
9. Orthographic views should be aligned and maybe we could reduce the
viewport's size to better organize the layout.
10. Write, below each orthographic viewport, the respective scale. To com-
plete the layout, insert additional elements (for instance, frame and draw-
ing information).
The PREVIEW command should display a view similar to the next diagram: