hi every body I have a problem with star-cd. I can't find undo. how can I come back to the last activity when make a mistake? if anyone knows how I can undo the activities please help me. thank you

you can't. there is no undo.

There is a vundo to undo the last vertex operation.

The older and more general command you are looking for is RECOVER. This replays all the commands since you last SAVEd.

You put in the last command you want it to execute, be careful not to make that command in the middle of a set of mouse picks.

It may sound inefficient, but often it is very disappointing to watch an hour's work whiz past in about 2 minutes of CPU time.

It works pretty well unless you have self modifying scripts, have overwritten cell and vertex files ,etc. and generally done things that mean the initial state cannot be replicated easily.

There is also an undo for vertex manipulation (VUNDO) and undelete commands for cells (CUNDELETE) and splines (SPLUNDELETE).

copy that...no undo!!!
Try to save frequently and at various model...and try the RESUME <filename> command when you need to recover a saved model.