Unreal Tournament, for example has got a waypoint system. Just add waypoints (many!) in your map while you edit it and then do a simple algorithm that knows what waypoint is visible to another. Calculate also distance between these two, so you know how long will it take to travel.

Then use A* for routefinding in your waypoint-link-net.
Good A* links and something about implementing A* for a 3d-game:
http://www-cs-students.stanford.edu/~amitp/gameprog.html

Unfortunately waypoint systems are not good for dynamic maps, but doors and lifts are not a problem.

So has anybody figured out how to do polygon based route finding in a randomly generated world that is fully dynamic (like an RTS)?

Are there any algorithms to find a path for a unit of any size on a map with polygons as obstacles? And do any of these algorythms deal with dynamic map changes?

There have been some papers written on pathfinding in a polygon based world. I found them while searching the web on "path finding" and "shortest path" and "mobile robots". Its been a while since I've read them, but I seem to recall the process being somewhat computationally extensive. You should be able to locate them via yahoo or alta vista pretty easily.

I've used the waypoint system (similar to what is described above) in a dynamic 3D world (just like described for a RTS) and when the world changed (walls destroyed, buildings built, etc.) we would evaulate and place new nodes (same as waypoints) and link them into the network via the nearest nodes. Then run Astar on the nodes to find the path. Moving units or other NPCs were not a problem, as we would collision detect on those within a specific range as the path was determined.

Just some ideas to consider ...