ISO/IEC 14496-16:2006 specifies MPEG-4 Animation Framework eXtension (AFX) model for representing 3D Graphics content. Within this model, MPEG-4 is extended with higher-level synthetic objects for specifying geometry, texture, and animation as well as dedicated compression algorithms. The geometry tools include Non Uniform Rational B-Splines (NURBS), Subdivision Surfaces, Mesh Grid, Morphing Space and Solid Representation based on implicit equations. The texture tools include Depth-Image based Representation and MultiTexturing. The animation tools refer to Non-Linear Deformers and Bone-based Animation for skinned models.
AFX also specifies profiles and levels for 3D Graphics Compression tools and the encoding parameters for 3D content. In addition, AFX specifies a backchannel for progressive streaming of view-dependent information.