A few notes on this prefab:

(1)  I swiped the original from the net, probably a Rust tutorial file, but I couldn't find it again when I looked for it.  Credit for construction of the elevator and walls belongs elsewhere.

(2)  The original scripts for the demo maps worked, but did not allow the user to go backward to the first map.  Figuring them out was difficult, very obtuse programming in the code.  I changed the scripts to make the multimanager do more of the work, greatly simplified the understanding of how it worked.

(3)  Another flaw of the original lies in objects which make the transition from one level to the other.  While the Wavelength tutorial is pretty good,

http://www.planethalflife.com/wavelength/levels/entities/index.html

the tutorial author neglected to mention that by not including a trigger transition, the carry over of monsters and items from one level to the other seems to be pretty far out from your info_landmark point.  If you move the trigger_changelevel code up a notch out from under the trigger_transition code on the editing tree, then delete the trigger_transition code altogether from both maps, you'll quickly see the problem illustrated.  There is a shotgun and shells on the floor of one level, while there is a crowbar on the floor of the other.  Without the trigger_transition code, if you don't pick up the objects on the floor and make a transition from one level to the other, the objects go with you from one level to the other.  This is logical when considering that walking down a hallway and making the transition in the hall, objects which were behind you should transition.  But this isn't so logical when using the elevator transition since now the objects which went with you were originally on another "floor" of your level.

Without the trigger_transition, monsters from quite far away in level 1 might show up in level 2, way far away from the elevator, and probably corresponding to the same points in world space as the room in which you suddenly found a critter which wasn't supposed to be there (this is what happened to me).  Objects close by make the transition as well, not just monsters.  The trigger transition needs a poly, preferably the same size as the inside of your elevator or a bit smaller, to transition the stuff inside the elevator (say you lured a scientist or barney with you) on the next level.

If you have questions on how the code worked, feel free to e-mail me at:

mmurray@knology.net

Good luck!

Mark Murray

P.S.  Those of you who upload your prefabs, please use the .map format rather than worldcraft.  Some of use different editors (such as Quark) which will not open worldcraft format files.