I have seen "MinNumberOfUndos=10" :)
What that? (I have made 24 undo without problem :)

An error script (It's my fault :)
I make a box 3 D (By corners) but clic the second corner on the "same line" ! (yes it's a shame :)
--> Error script "Line 126 Column 0"
That don't block the prog :)
I close the message, the 2 points are automaticaly deleted and I can continue :)
Maybe a message like "you have made a mistake" will be appropriate :)

There are 2 settings that control how many undos you will have available:

[Undo]
MaxMemorySizeMB=20
MinNumberOfUndos=10

The amount of memory one undo action takes up totally depends on the complexity of your objects. Highly complex objects will take up more memory.

MoI always saves at least "MinNumberOfUndos" number of objects in the undo stack, no matter how much memory it takes up.

It will then continue to keep additional undo objects around until the saved undo objects take up more than MaxMemorySizeMB memory size.

So with the default settings, you will always have at least 10 actions, and then it allows more than that until it fills up 20 megabytes.

One cool thing - objects that are saved for undo are zipped inside memory to take up less space.

You will normally get quite a large amount of zipped objects within 20 megabytes, so normally you should have a large number of undos available.

Thanks for reporting the script error - script errors like that are caused by a bug in a command. I'll fix this one up. I eventually want to have some place to output error information, I just haven't figured out quite where to put it yet.

- Michael

Thx for all explanations :)