SceneKit is a very simple to use 3d Game Framework for iOS made by Apple but it is very powerful.
I see the games that are made with SceneKit and they look really awesome.
Having a 3d GameEngine for b4i will be a great addition. Don't you think?
Create 3D games and add 3D content to apps using high-level scene descriptions, and easily add animations, physics simulation, particle effects, and realistic physically based rendering.