"Nothing to revert"

After some time working in Rhino the undo command suddenly breaks.
The command line will say: “Nothing to revert.”

Any idea what the problem might be?

maybe you run out of undo steps. check in the options how much memory you have for Undo steps

It has more to do with what the previous operations did.
For example, if you’re drawing curves, they don’t take much memory to keep track of them. On the other hand, of you do a Boolean operation between several very complicated polysurfaces, and big meshing operation, 512MB will be fill up or overflowed pretty easily.

A better option may to intentionally use the Incremental Save command. It’s like SaveAs except it automatically names the file but unlike SaveAs, it leaves you in your current file.
Then after a while, ever after multiple editing sessions, if you change your mind and want to get back to that earlier state when you did the incremental save, just open it and go your other direction.


Thank you for both your input.
First of all the undo memory was indeed quite low (set to only 256 mb). I bumped this and until now I had no more problems.

You shed some valuable light on this situation! It’s now much more logical how this error message comes to life.

The other thing to remember is the memory you have carved out for Undos, is not available for modeling calculations. If your system is short on memory in the first place, increasing the carve out for undos will make your system page to disk sooner as it will run out of working memory faster.

Perhaps the metaphor of ice in a water pitcher will help. If you fill a pitcher with ice, there isn’t much room left for water, so you can’t fill many glasses and are returning to the spigot much sooner.
You want just enough ice to keep the water cold but maximize the amount available for filling glasses.
It’s a balance.