When you draw new objects, they are created in relation to the current coordinate system.
Set the current UCS
Choose Tools > Named UCS.
Select the desired UCS and press Set Current button.
Click OK button.
Command line DDUCS
UCS: Manages user coordinate systems
UCSICON: Manages user coordinate systems
UCSMAN: Manages defined user coordinate systems
System Variables Reference
ERRNO: Displays the number of the appropriate error code when an AutoLISP function call causes an error that ZWCAD detects
PUCSBASE: Stores the name of the UCS that defines the origin and orientation of orthographic UCS settings in paper space only
UCSFOLLOW: Generates a plan view whenever you change from one UCS to another
UCSNAME: Stores the name of the current coordinate system for the current viewport in the current space
UCSORG: Stores the origin point of the current coordinate system for the current viewport in the current space
UCSXDIR: Stores the X direction of the current UCS for the current viewport in the current space
UCSYDIR: Stores the Y direction of the current UCS for the current viewport in the current space
UCSICON: Displays the UCS icon for the current viewport using bitcode
UCSVP: Determines whether the UCS in active viewports remains fixed or changes to reflect the UCS of the currently active viewport