Wow, the amount of ■■■■■■■■ and misinformation in this thread is making my head explode…
First off, a game engine consists of a graphics pipeline (rendering engine), physics engine and a sound engine. That’s it. All the other stuff that it can include (AI, inventory, networking, memory management, threading, …) are just gimmicks. They don’t have to be part of a game engine.
That used to be the case 30 years ago, but it hasn’t been the case for ages. Developing and maintaining an engine is expensive. And I mean really expensive. You can gain much more my taking a off-the-shelves engine (Cryengine, UE, Havoc, Leadwerks, …) and just writing custom code for the stuff you want to improve on, while using the rest.
Game engines are no longer tightly coupled with the games they’re developed for, because it makes no economic sense to do so. They’ve simply grown way too complex for that and you also don’t want a new hire having to spend 3 months figuring out how your engine works before he can get productive.
Game engines are frameworks, not games. They’re built to be reusable across games.
As already mentioned, CCP uses their in-house developed CARBON engine. It replaced the formerly used Trinity Engine, which in turn replaced the first engine they used (I think it was Trinity 1.0 and 2.0, but not entirely sure). But considering that CCP is constantly making adjustments and improvements, the CARBON engine they introduced with Incarna is light years away from the current state of the CARBON Engine.