UCS — UCS

Manages user coordinate systems.

• Command: UCS · Global name: _UCS
• Ribbon: View › Coordinates
• Menu: Tools

Changes the user coordinate system (UCS): an origin and X and Y axes of your own, moved or rotated with respect to the world coordinate system (WCS). It is useful to draw aligned with a rotated building or to measure from a corner of the plot.

Usage

1. Enter UCS or click the button.
2. Specify the new origin, or choose an option. Enter goes back to the world system.

Specify origin of UCS or [NAmed/OBject/Previous/World/Z] <World>:

3. Specify a point on the positive X axis; Enter keeps the axes as they were and only changes the origin.

Specify point on X-axis or <accept>:

4. Press Enter (or specify any point) to accept.

Specify point on the XY plane or <accept>:

Options

• NAmed (NA): saves the current UCS with a name, restores a saved one or deletes it; ? lists them.

Enter an option [Restore/Save/Delete/?]:
Enter name to save current UCS or [?]:

• OBject (OB): aligns the UCS with an object: a line (origin at the endpoint nearest to the selected point), a circle or an arc (origin at the center), a polyline (its first segment), a text or a block (its point and rotation), an ellipse or a point.

Select object to align UCS:

• Previous (P): goes back to the previous UCS. The last ten of the session are remembered.
• World (W): goes back to the world system.
• Z: rotates the UCS about its origin; Enter rotates 90°.

Specify rotation angle about Z axis <90>:

• X and Y: rotate the UCS about its X or Y axis (Enter: 90°).

Specify rotation angle about X axis <90>:

• ZAxis: new origin and a point on the positive Z axis; X and Y come from AutoCAD's arbitrary axis algorithm. Type x,y,z to give the Z.

Specify new origin point <0,0,0>:

• View: UCS parallel to the screen, with the current origin.
• Move: changes the origin without rotating the axes; Zdepth moves it along the Z axis.

Specify new origin point or [Zdepth] <0,0,0>:

• Orthographic: the six standard UCSs (Top, Bottom, Front, Back, Left and Right) with the current origin.

Enter an option [Top/Bottom/Front/BAck/Left/Right] <Top>:

• Apply: applies the current UCS to the viewports (here, the only active one).
• Face: not available: it would need the face of a 3D solid to be selected.

Notes

• 2D drawing works in the XY plane: a UCS rotated about X or Y (X, Y, ZAxis, View, Orthographic) is saved and shown in the icon, the 3D view and AutoCAD, but 2D commands treat it as the World UCS.
• With a UCS, the coordinates you type and those shown in the status bar are in the UCS. To type a point in the world system, put an asterisk in front: *100,50 or @*20,0.
• Ortho, the grid, snap and the crosshairs are aligned with the UCS, and so are RECTANG and the rotation of TEXT. Polar tracking, dynamic input and the angles of other commands stay on the world axes.
• Only UCSs in the plane: the 3-point option does not tilt the XY plane.
• It is saved as in AutoCAD (UCS table and the UCSORG, UCSXDIR and UCSNAME variables): AutoCAD opens the drawing with the same UCS.
• PLAN rotates the view so that the UCS X axis is horizontal. The icon is controlled with UCSICON.

See also

UCSMAN · PLAN · UCSICON · Coordinates and data entry