Composite Lighting Simulations with Lighting Network


A whole variety of different techniques for simulating global illumination
in virtual environments have been developed over recent
years. Each technique, including Radiosity, Monte-Carlo ray- or
photon tracing, and directional-dependent Radiance computations,
is best suited for simulating only some special case environments.
None of these techniques is currently able to efficiently simulate all
important lighting effects in non-trivial scenes.
In this paper, we describe a new approach for efficiently combining
different global illumination algorithms to yield a composite
lighting simulation: Lighting Networks. Lighting Networks can exploit
the advantages of each algorithm and can combine them in
such a way as to simulate lighting effects that could only be computed
at great costs by any single algorithm. Furthermore, this approach
allows a user to configure the Lighting Network to compute
only specific lighting effects that are important for a given task,
while avoiding a costly simulation of the full global illumination in
a scene.
We show how the light paths computed by a Lighting Network
can be described using regular expressions. This mapping allows us
to analyze the composite lighting simulation and ensure completeness
and redundant-free computations. Several examples demonstrate
the advantages and unique lighting effects that can be obtained
using this technique.