The other problem I have with it is that it is largely theoretical, and does not discuss the specifics of rendering with a 3D API such as OpenGL or Direct3D. Nonetheless, the article got me really excited when it showed this screenshot: <a href="http://www.gamasutra.com/gdce/2001/jensen/fig_3,4.gif">http://www.gamasutra.com/gdce/2001/jensen/fig_3,4.gif</a> along with its wireframe version: <a href="http://www.gamasutra.com/gdce/2001/jensen/fig_3.5.gif">http://www.gamasutra.com/gdce/2001/jensen/fig_3.5.gif</a> .