2004

Use Coordinates and Coordinate Systems | 225
To delete a UCS
1 From the Tools menu, choose Named UCS.
2 In the UCS dialog box, Named UCSs tab, select the UCS you want to
delete.
3 Press
DELETE or right-click and choose Delete from the shortcut menu.
You cannot delete the current UCS or a UCS with the default name
UNNAMED.
UCS toolbar
Command line
UCSMAN
Specify Drawing Planes in 3D (UCS)
Control of the user coordinate system is essential for effective 3D modeling.
Use World and User Coordinate Systems in 3D
AutoCAD provides two coordinate systems: a fixed coordinate system called
the world coordinate system (WCS) and a moveable coordinate system called
the user coordinate system (UCS). The UCS is useful for entering coordinates,
defining drawing planes, and setting views. Changing the UCS does not
change your viewpoint. It changes only the orientation and tilt of the
coordinate system.
If you are creating 3D objects, you can relocate the UCS to simplify your
work. For example, if you have created a 3D box, you can edit each of its six
sides easily by aligning the UCS with each side as you edit it.
You relocate a UCS by choosing the location of the origin point and the
orientation of the XY plane and the Z axis. You can locate and orient a UCS
anywhere in 3D space. Only one UCS is current at any given time, and all
coordinate input and display is relative to it. If multiple viewports are
displayed, they share the current UCS. With the
UCSVP system variable
turned on, you can lock a UCS to a viewport, automatically restoring the UCS
each time that viewport is made current.
When drawing in 3D, you specify X, Y, and Z coordinate values in either the
world coordinate system (WCS) or the current user coordinate system (UCS).
The illustration below shows the X, Y, and Z axes of the WCS.