Rendering For each node of the graph a panoramic rendering is done (made of 6 axis-aligned renderings).
For each arc of the graph a panoramic video is created by densely sampling the path making a panoramic rendering for each sample.
These renderings can be simple OpenGL renderings (that is, with local illumination model of simple effects such as shadow mapping or ambient occlusion), or complex global lighting.
It all depends of what we want our final result to be, how much computational power we have and hoe much time are we willing to wait.