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 UCSs tab of the (Named) 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.
NoteGenerally, it is
recommended that you leave the elevation set to zero and control
the
XY plane of the current UCS with
the
UCS command.
Change the UCS in Paper
Space
You
can define a new UCS in paper space just as you can in model space;
however, the UCS in paper space is restricted to 2D manipulation.
Although you can enter 3D coordinates in paper space, you cannot
use 3D viewing commands such as PLAN and VPOINT.
Save and Restore UCS Locations
by Name
If
you plan to work extensively in 3D, you can save named UCS locations,
each having a different origin and orientation, for various construction
requirements. You can relocate, save, and recall as many UCS orientations
as you require.
To define a new UCS origin
in 3D
-
- Specify a point for the new origin.
The UCS origin (0,0,0) is redefined at the point
you specify.
To define a new UCS with
a specified Z axis
- Specify a point for the new origin.
The UCS origin (0,0,0) is redefined at the point
you specify.
- Specify a point that lies on the positive Z axis.
To define a new UCS with
particular X and Y axes
- Specify a point for the new origin.
The UCS origin (0,0,0) is redefined at the point
you specify.
- Specify a point that lies on the positive X axis.
- Specify a point that lies on the positive Y axis.
To shift the XY plane
- Specify an origin point for the new UCS
(1).
For example, in a large
drawing, you might specify an origin point near the area in which
you want to work.
- Specify a point to indicate the horizontal
orientation of the new UCS (2). This point should be on the positive
portion of the new X axis.
- Specify a point to indicate the vertical
orientation of the new UCS (3). This point should be on the positive
portion of the new Y axis.
The UCS, including grid, shifts to represent
the X and Y axes you have
specified.
To select a UCS preset
-
- In the UCS dialog box, Orthographic UCSs
tab, select a UCS orientation from the list.
- Click Set Current.
- Click OK.
The UCS changes to the selected option.
To restore the location
and orientation of the previous UCS
The previous UCS is restored.
CommandsELEV
Sets elevation and extrusion
thickness of new objects.
UCS
Manages user coordinate
systems.
UCSMAN
Manages defined user
coordinate systems.
System VariablesELEVATION
Stores the current elevation
of new objects relative to the current UCS.
UCSVP
Determines whether the
UCS in viewports remains fixed or changes to reflect the UCS of
the current viewport.
