How to support collaborative modelling with the emerging standard MPEG-4 MU

In a collaborative modelling environment, multiple users may interact in a virtual environment to deform or modify shared 3D objects (e.g., for modelling and visualization of virtual prototypes). The challenges to collaborative modelling are related mainly to four aspects: user interaction with the virtual modelling environment, 3D object concurrent editing, consistency maintenance among client terminals and real time rendering of the modified 3D objects. The use of Non-Uniform Rational B-Splines (NURBS) surfaces accelerates the rendering process since a small number of control points are used to represent the objects, resulting in a large data compression. Nowadays a number of technologies has either emerged or evolved to support 3D environments, such as: X3D, Java3D and MPEG-4 MU. This paper shows how the emerging MPEG-4 MU standard can be used to support real-time modelling through NURBS in a shared virtual environment among multiple client terminals.