FreeGameDev

Currently im working to implement scene load/unload in my game project. Im using Ogre, and I have found a problem, at least in version 1.6: to remove the terrain I have to clear the scene, removing also the characters nodes. My idea was just to make the characters nodes invisible, but now seems that Ill have to figurre out a way to recreate the nodes when the map is loaded again.
I would like to know how other developers are dealing with such problem, what do they do with scene nodes when a map is unloaded, etc. Any opinions?

one possibility would be to make one "root"-node per level, and set that one invisible (subnotes won't be drawn, so you only need to toggle this one). i think it's also quite common to clear the entire scene, saves ram.