Rotating your View
Have you ever had that horrible experience where someone has rotated your background drawing? The first tenet of shared backgrounds is "Never Move the Background." If you need to view a background drawing in a different orientation, rotate your viewing direction, don't rotate the drawing.
You can rotate your viewing direction in Model Space or from within a Model Space Viewport. Consider the following plan:
The first thing to notice is the UCS Icon in the lower left corner of the Viewport. (If your UCS Icon is not on, let me strongly urge you to consider turning it on via the UCSICON command.) The icon indicates that the current coordinate system is World with Y increasing upwards and X increasing to the right.
Let's rotate the viewing direction to more comfortably view, plot, annotate, or work on the model.
Use the UCS command to create a User Coordinate System aligned with the building. I used the 3-point method to exactly align my UCS with the building.
Command: UCSNotice the UCS Icon and crosshairs are now aligned with the building.
Current ucs name: *WORLD*
Enter an option [New/Move/.../Apply/?/World]
Specify new origin point <0,0,0>: [pick Pt1]
Specify point on positive ... X-axis: [pick Pt2]
Specify point on positive-Y... of the UCS XY plane:
You can leave the UCS set, or return to World coordinates, depending on your needs.
Alternate Method: The old DVIEW command with the Twist option will rotate the viewing direction without rescaling the Viewport, but you must know the rotation value because you cannot "show" it to the DVIEW command by picking points.