We've always used a lot of our own stuff, mixed with other middleware that we liked. Coming off of Fallout 3, we made a pretty big list of what we wanted to change technically. So we redid the rendering, lighting, shadows, animation, faces, foliage, mountains, scripting, interface and more. And by the time we got through it all, it was clear the technology was new enough to give it its own name, The Creation Engine. Same with our editor, The Creation Kit. They go together as technology.

Some of that you'll notice as a player, like shadows, mountains, and the animations; some you won't, like how scripting or pathfinding works internally. If you looked quickly at our editor, it behaves similar to our old ones; it just does a lot more, and does some old things in better ways. But we don't change things just to change them. We still use the nif file format, because it worked fine for what we're doing and our modders know it well. We still use some middleware that we like, such as Havok. We're not just using their physics this time, but their animation system, Havok Behavior. It makes a dramatic difference in how the game looks and plays. Overall though, the paradigm for how we build these huge worlds has not changed dramatically, we just want it to look better and play more smoothly.