Just like using other software, you can undo what you’ve done.
The Undo command used to reverse the effects of CAD commands.
However, the Undo command is not available for some commands such as Open, Close, or Save a viewport or a drawing, display information, change the display mode, regenerate the drawing or export the drawing to different formats.
How to access the Undo command
Find Quick Access toolbar > Undo, as shown in the following picture,
Alternatively, we can right-click in the drawing area without selecting an object, the Undo command is shown as below,
Or we can just enter “UNDO”, shown as below,
After executing the command, we’ll get the following prompt,
Specifying the number of operations here has the same effect as entering U multiple times.
For example, if you want to undo the last operation, enter 1; if you want to undo the operation before your last operation, enter 2.
How U command is different from the Undo command ?
Many people think of U as a shortcut for Undo command just like L is the shortcut for Line command, however, this is not the case.
Entering U and entering Undo would give you different prompts in the command line, shown as below,
Actually, the U command equals entering UNDO 1. U command is obviously more convenient since it requires less entering and in the design process, few of us would remember the exact number of operations needed to reverse, just repeating U will do.
Other Similar commands
The OOPS is used to restore the last deleted objects. This command can restore the last deleted objects by ERASE command. The OOPS command can not restore parameters, actions or grips in Block Editor, as well objects deleted by the PURGE command.
The LAYERP command is used to undo the last change or last group of changes of layer settings.
Users can undo previous changes of layer settings (such as color or lineweight) and display Restored previous layer status at the Command prompt. All changes of layers are traced. Users can use this command to undo changes by “Layer” control or Layer Properties Manager.
However, layers renamed, layers deleted and layers added can’t be restored by LAYERP command.