Three-dimensional (3D) representation is one of the most important category of Computer Graphics (CG) and multimedia. Huge architectural buildings, objects, even humans can be represented using 3D graphics in such a way that it is difficult to distinguish between real and virtual objects. Today, all the advanced devices such as Personal Digital Assistants (PDAs), mobile phones, laptops and so forth, are now “3D capable which provide high depth to the information presented.
Although there are many formats of this 3D graphics such as The MPEG group, Binary Format for Scenes (BIFS) and by the Synthetic Natural Hybrid Coding (SNHC) subgroup for Animation Framework Extension (AFX), the discussion is going to be about MPEG because of its importance.
MPEG provides a complete framework for multimedia delivery, and recently, with the MPEG-7, MPEG -4 and MPEG-21 standards, it even allows for the inclusion of media objects semantics as well as evolved processing, such as Digital Item Adaptation (DIA) or intellectual property management and protection (IPMP).
Moreover, adaptation is one of the most important issues considering 3D graphics delivery, and it offers a wide range of possibilities; for instance, by driving single content delivery towards multiple devices.The underlying approach uses a description of scalable encoded data to allow for bitstreams modifications (as illustrated by Figure 1), which is often done by using generic Bitstream Description Language (gBSDL).
Some researches are oriented towards optimization for a specific device; other work is taking advantage of some computer graphics (CG) processing, such as to allow 3D playback on light devices. Other approaches use these devices as a display only. Another work is for appropriate graphics API on light devices, the major one being probably OpenGL ES for embedded and mobile devices.
The production of 3D graphics lies in two steps
- Designing of 3D shapes.
- Creation of animation sequences applied on 3D models.