Houdini 19.0 HScript commands undoctrl

undoctrl HScript command

Turns undo on or off, or clears undo memory.

Replaced by


undoctrl on|off

undoctrl [-s] [-c]

Turning off the undo mechanism can cause scripts to execute with greater speed, but the changes made by the script will not be undo-able.

Please use with caution, remembering to turn undo back on at the end of the script. Running this command by itself in the textport will cause the undo stack to be corrupted.

If you don’t specify any options, the command prints the current state.



Print the memory usage of the undo stack.


Clear the undo stack, freeing the memory used.