MPEG 3D graphics representation

The Tri-Dimensional Graphics (3DG) information coding tools of MPEG-4 are mostly contained in MPEG-4 Part 16, Animation Framework eXtension (AFX), and focus on three important requirements for 3DG applications: compression, streamability and scalability. There are tools for the efficient representation and coding of both individual 3D objects and whole interactive scenes composed by several objects. Usually, the shape, appearance and animation of a 3D object are treated separately, so we devote different sections to each of those subjects, and we also devote another section to scene graph coding, in which we describe how to integrate MPEG-4's 3DG compression tools with other (non MPEG-4-compliant) XML-based scene graph definitions. A final section on application examples gives hints on the flexibility provided by the 3DG toolset of MPEG-4.