Yes, the Edit->Copy function will copy all geometry and materials into 3DSimED's internal clipboard, and with a large drawing you will also soon have a large undo stack, so it does not take long to run out of memory.
A 64-bit version would help but large drawings really slow the program down so there needs to be some big internal work to counter that downside.
2 Weeks later and I am 100% at home with 3DSimEd - thanks Dave for a great application.
Any chance it will go 64bit to get past the 3.4GB memory limit?
While working with a very populated map, 3DSimEd file size about 600mb I notice it only takes 2 or 3 copy/paste actions to go from 1.2GB memory use in the app to surpass the 3.4GB mark and get the dreaded Out of Memory error when trying to save.
Is the entire data set being placed in the clipboard to allow for Undo operations?