This is an FPS camera system that is based around my WASD movement library. All you have to do is create a suitable camera in the map panel of the editor and select it instead of the placeholder variable 'Camera' in the map initialization trigger. It has 8 direction movement and can be set to move and rotate a unit with the camera by setting the view type global variable as 'Third Person' and turning on the unit rotation trigger. This can be done in game, an example being getting into a vehicle. What sets this FPS engine apart is the pathing system. This keeps you from walking through/over/into things like cliffs, units, and doodads without the use of a dummy object. It's entirely pre-made for you, which should save a lot of work.
[UPDATE] There's a new version with pathing perfected. V2.0 of the trigger library is available in the files page and once again there's a demo map to accompany it to demonstrate the library's features and show how to implement the library.
The pathing is now working properly. There's three types of pathing stops now: terrain (cliffs, edges of ramps), units (ground only), and structures (again ground only). This means that you can't walk off or over cliffs, you can't walk through units, and you can't walk through buildings. You can however walk under flying units, walk under flying buildings, and walk up or down ramps.
The map has two ground units of different types to try to walk through, two ramps to demonstrate terrain pathing, cliffs to demonstrate terrain pathing, a flying unit to walk under, a building to try to walk through, and a flying building that you can walk under. All thse things demonstrate what's valid for movement and what isn't.