3D Studio Max Undo and Redo Urdu Tutorial

The Undo command reverses the last operation performed on any selected objects. Redo reverses the last operation performed by the Undo command. Some actions cannot be undone: for example, applying the Collapse utility or Reset Transform utility, or saving a file, which overwrites the previous version. When you know something cannot be undone, use Hold first. Then if you want to undo it, use Fetch. Hold and Fetch are also commands on the Edit menu.
After you perform an action that is undoable, the Edit menu shows the name of the function to be undone. After you undo an action, the Edit menu shows the name of the function you can redo.
Undo and Redo are also available as buttons on the main toolbar. You can right-click the Undo or Redo button to display a box that lists the last operations performed. You can highlight and reverse any number of these operations in sequence with the respective Undo or Redo command. By default, there are 20 levels of Undo. You can change the number of levels with the Customize > Preferences > General tab > Scene Undo group.

3D MAX Urdu Tutorials | Undo and redo Levels by xpacademy