With the AI mesh, it's basically a guide that leads the bots to the player and prevents them from trying to run through walls to reach the player. There are 3 different modes for the mesh, they can be moved as with any prop. Use the create new face to make a new panel of the mesh. The vertex mode moves corners, edge mode moves one side of the plate, and the face mode moves the whole panel. Look at the ni maps and their meshed to see how they work. Also as Alpha said, remember the barriers, they need to be EVERYWhere so that the players don't glitch or have cades stuck in props and other nasty stuff.
Video Guide, ai mesh mentioned 44~ minutes in: http://youtu.be/bnipiwUW7rk
Good luck:p
Video Guide, ai mesh mentioned 44~ minutes in: http://youtu.be/bnipiwUW7rk
Good luck:p