Setting Undo Controls

The UndoN command reverses previous operations and lets you control undo operations.

The steps made during the current drawing session are recorded in an undo register. The steps in register list can be withdrawn by using undo sequentially, where each undo removes the previous step. The undo register is kept only with the current session.

You can repeat the UndoN command until you have canceled all working steps stored in the undo register (indicated by the "Nothing to undo" message).

Canceling the last work step (the first step appearing in the undo register) is the normal mode of the command.

To use the UndoN command:

1. Type UndoN at the command prompt.
2. Type the number of steps to undo, or specify an option:
   • Auto: Prompts you to turn on or off undo auto mode. When undo auto mode is on, all actions of a single command are grouped as if they were one action that can be undone with a single U command.
   • Back: Lets you mark the listed steps of a task and cancel all unmarked steps in one operation. The Back option restores the task to the previously marked state.
   • Begin: Lets you group steps. You can cancel grouped steps with a single undo. Use the Begin option to define the beginning of a group of steps.
   • Control: Allows access to these options for controlling the undo process:
     • All: Indicates that all working steps are recorded for the undo function.
     • Combine: Determines whether multiple, consecutive zoom and pan commands are combined as a single action for undo and redo operations.
     • None: Indicates that no steps are registered in the undo register. The U and the UndoN command have no further effect. Setting this option also deletes the current undo register.
     • One: Fixes the number of the steps you can cancel at the value 1. Only the last working step is recorded in the undo register.
   • End: Lets you group steps. Use the End option to define the end of a group of steps.
   • Mark: Lets you mark the listed steps of a task and cancel all unmarked steps in one operation. The Mark option defines the current state of the drawing as a state that can then be restored by using the Back option.

Access

Command: UndoN