For the Crytek stuff, you’ll have to search for Mikko Mononen’s talk at the Paris Conf. But specifically I was talking about the tactical points system that Matthew Jack did for CryEngine which you should be able to see here: http://docs.cryengine.com/display/SDKDOC4/AI
You might need a login to that, I can’t remember.
Point being, its more complicated than just a bunch of LOS checks if you want really interesting combat encounters. Oh while I’m at it, search for a talk by one of the Insomniac designers about combat encounters to see some stuff from a designer perspective (it was a GDC talk, but I’m sure I saw it on the Insomniac site).