Source Engine - In The Belly Of The Beast?

Thanks to Half-Life 2 Fallout for its fan-written feature discussing the content of Valve's Source videogame engine, as used for Half-Life 2. The piece explains: "The Source engine is not just a 3D engine (in the sense it's not just a renderer) -- it contains many different modules that are all brought together into one package", and tries to clarify discussion on subjects as diverse as lighting ("Something that has caused confusion in the past is 'dynamic lights' [in the Source engine].... All a light has to be in order for it to be qualified as dynamic is to be able to move and have changeable attributes.... It doesn't mean that it will [necessarily] cast real time shadows like in Doom 3 or Unreal Engine 3.0"), and in-game water ("When Valve say the water is physically simulated, they mean objects have buoyancy. They don't mean the Source engine has fluid dynamics.")