A method and a processing device for performing rendering are disclosed. The method comprises generating a base hierarchy tree comprising data representing a first object and generating a second hierarchy tree representing a second object comprising shared data of the base hierarchy tree and the second hierarchy tree and difference data. The method further comprises storing the difference data in the memory without storing the shared data, and generating an overlay hierarchy tree comprising the shared data, the difference data, and indication information indicating nodes of the overlay hierarchy tree that comprise the difference data. The method further comprises rendering the first object using the data stored for the base hierarchy tree, and rendering the second object using any one or a combination of the shared data, the difference data, and the indication information.