Direct3D Retained Mode API is designed for manipulating 3D objects and managing 3D scenes. Retained Mode makes it easy to add 3D capabilities to existing Windows-based applications or to create new 3D applications. Its built-in geometry engine supports advanced capabilities like key frame animation and frees you from creating object databases and managing the internal structures of objects. In other words, after using a single call to load a predefined 3D object, the application can use simple methods from the API to manipulate the object in the scene in real-time without having to work explicitly with any of the internal geometry.
Retained Mode is built on top of Immediate Mode and is tightly coupled with the DirectDraw® application programming interface (API). Microsoft will incorporate Retained Mode into a future version of Windows. For more information, see DirectDraw and Introduction to Direct3D Retained-Mode Objects.