http://www.ac3d.org/I happen to just stumble upon this little shareware program... though it's a little dos'sy it's exelent it what it can do.. I incourage anyone to check it out! B)
I've used it before, it is very easy to use but not fast enough for really large worlds.
Perhaps not... but you can always just make small segments of those worlds and make each segment like a diferent level or something.... I plan on doing something like that when I get into designing some VRML worlds.. though that's not Blitz related, it's still pretty cool
AC3D *IS* a really nice modelling program since v2.x.
Very easy for modelling a charactor or smapp maps, works well with .X export, I usually export model to MilkShape for further Animating/Editing.