Quote Originally Posted by Kiote View Post
This is about right. The simple fact is that when you Change the Engine of a game, you have to rebuild everything. You can't just drag and drop parts of the old world to the new world. It might be similar, but nothing will be the same.
This is absolutely false. Model data is a list of vertices in 3D space. Model placement data is a list of points in 3D space attached to model data. Textures are bitmaps, art assets which are not procedurally generated, which have texture maps, which again are just points, these do not change.

Changing the engine presents a good opportunity to modify things yes, but if they so wanted they could make everything exactly the same from a model data/texture perspective. What they're changing is the way objects in the game are rendered using shading, lighting, and rasterization. The changing of the world is not a result of them changing the engine, it is a result of player feedback.