I strongly believe that they are a collection of pre-contstructed maps, you just start at random points. I can usually recognize a battlefield from before.
If they're pre-constructed, then the occasional weirdness you get (like 200-foot pillars of rock with you atop them) must be the product of a truly twisted sadist.
They're randomly generated. Armagan has said so before and I believe the files are there for all to see in M&B's root directory.
I strongly believe that they are a collection of pre-contstructed maps, you just start at random points. I can usually recognize a battlefield from before.