2011

Define a UCS by selecting an object
Method of determining UCSObject
its extrusion direction. The object you select to establish a new
UCS has a rotation angle of zero in the new UCS.
The insertion point of the object becomes the new UCS origin,
and the new X axis is defined by the rotation of the object about
Text, block refer-
ence, attribute
definition its extrusion direction. The object you select to establish a new
UCS has a rotation angle of zero in the new UCS.
Previous
Restores the previous UCS.
The last 10 user coordinate systems created in model space and the last 10
created in paper space layouts are retained. Repeating this option steps back
through one set or the other, depending on which space is current.
UCS definitions saved in one viewport are not retained in the Previous list for
a different viewport. However, if you change a UCS setting within a viewport,
the last UCS setting is retained in the Previous list. For example, changing the
UCS from World to UCS1 would retain World at the top of the Previous list.
If you then switch viewports with Front as the current UCS, and then change
the UCS to Right, the Front UCS is retained at the top of the Previous list. If
you then choose the UCS Previous option twice in this viewport, the UCS
setting changes to Front, and then back to World. (UCSVP system variable)
View
Aligns the XY plane of the user coordinate system to a plane perpendicular to
your viewing direction. The origin point remains unchanged, but the X and
Y axes become horizontal and vertical.
World
Sets the current user coordinate system to the world coordinate system (WCS).
The WCS is the basis for all user coordinate systems and cannot be redefined.
1076 | Chapter 21 U Commands