ZWCAD lets you select a preset UCS. The six planes defined by looking along the x,y,z axes align the UCS with the top, left, front, bottom, right, or back, based on either the WCS or the current UCS in effect when you select the tool. You can also select the previous UCS, align the UCS to the current view, or select the WCS.
When you select a UCS, the cursor orientation and UCS icon change to reflect the new UCS.
The display does not change, however, unless you select the Change View To Plan View Of The Selected UCS check box.
After you align the UCS to a preset UCS, you can use "Named UCS" from the Tools menu to save the current UCS.
To select a preset UCS
Choose Tools > Named UCS.
Choose Orthographic UCS tab and select the desired UCS, then click 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