The transformation pipeline is considerably more complex than that for Version 1:
Figure 5.1: 3D Pipeline
A major activity is back face clipping which is quite time consuming. Faces have to be defined in the same order, anti-clockwise, and then the normal establishes the direction it is pointing. Once all the faces to be rendered are known, it is necessary to order these correctly for rendering and that sort procedure is quite difficult when faces overlap. It is a significant XSLT transformation involving recursion.
Full details of the system are given in Peter Gould's dissertation and an Overview is given in the SVG Open Paper at the Enschede Conference. Some examples of the output quality are shown on the following slides. Although this technique has not been used in animating the logos so far, it is an option if the need arises. For the Raleigh Conference we managed to cheat sufficiently not to require hidden line elimination.