The user coordinate system (UCS) establishes the location and orientation of a movable Cartesian coordinate system. The UCS is an essential tool for many precision operations.
The UCS defines：
- The XY plane, also called the work plane or construction plane, on which objects are created and modified
- The horizontal and vertical directions used for features like Ortho mode, polar tracking, and object snap tracking
- The alignment and angle of the grid, hatch patterns, text, and dimension objects
- The origin and orientation for coordinate entry and absolute reference angles
By default, the UCS icon appears in the lower-left corner of the drawing area for the current model viewport. The UCS in each paper space layout is displayed as a drawing triangle.
Methods for invoking UCS #
1，Click Menu: View/UCS
2，Enter Command line: UCS
World #
Aligns the UCS with the world coordinate system (WCS).
X, Y, Z #
Rotates the current UCS about a specified axis.
Point your right thumb in the positive direction of the X axis and curl your fingers. Your fingers indicate the positive rotation direction about the axis.
Point your right thumb in the positive direction of the Y axis and curl your fingers. Your fingers indicate the positive rotation direction about the axis.
Point your right thumb in the positive direction of the Z axis and curl your fingers. Your fingers indicate the positive rotation direction about the axis.
You can define any UCS by specifying an origin and one or more rotations around the X, Y, or Z axis.
Z Axis #
Aligns the UCS to a specified positive Z axis.
The UCS origin is moved to the first point and its positive Z axis passes through the second point.
