MPEG-4 toward solid representation

The limitations imposed on three-dimensional (3-D) rendering by the current polygonal pipeline are becoming apparent in several contexts. In order to surpass these limitations, applications will require modifications to the rendering process that will be more significant than just increasing the number of polygons processed per second. This paper addresses one of the most forward-looking features of MPEG-4, aimed at providing a framework for a smooth evolution toward future rendering engines. It covers the motivations that help sustain the inclusion of solid representation of 3-D objects into the standard, the nodes that support it, and their contribution to 3-D functionalities of the future. The range of applications is thus extended from visualization and animation to ones using exact geometry representation and solid 3-D space as in CAD/CAM/AEC and medical applications.