2011

Table Of Contents
Control the User Coordinate System in 3D
Several methods are available for manipulating the user coordinate system in
3D. You can also save and restore user coordinate system orientations.
You define a user coordinate system (UCS) to change the location of the 0,0,0
origin point, the location and rotation of the XY plane, and the orientation
of the XY plane or Z axis. You can locate and orient a UCS anywhere in 3D
space, and you can define, save, and recall as many saved UCS locations as
you require.
If multiple viewports are active, you can assign a different UCS to each
viewport. 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.
Define the UCS Location
You can define a UCS in the following ways:
Specify a new origin (one point), new X axis (two points), or new XY plane
(three points).
Align the UCS by selecting a face on a 3D solid object. The selection can
be on a face or on an edge of the solid.
Align the new UCS with an existing object. The origin of the UCS is located
at the vertex nearest to where the object was selected.
Align the new UCS with the current viewing direction.
Rotate the current UCS around any of its three major axes.
Reorient the XY plane by specifying a new Z axis.
Use UCS Presets
If you do not want to define your own UCS, you can choose from several
preset coordinate systems. The images on the Orthographic tab of the UCS
dialog box show the available choices.
Change the Default Elevation
The ELEV command sets the default Z value for new objects above or below
the XY plane of the current UCS. This value is stored in the ELEVATION system
variable.
216 | Chapter 16 Use Precision Tools