Lessig, ChristianFiume, Eugene2015-02-232015-02-2320101467-8659https://doi.org/10.1111/j.1467-8659.2010.01736.xLight transport is often characterized within a high-dimensional space although practitioners have long known that it commonly behaves as a much lower-dimensional phenomenon. We study the effective dimension of light transport over a neighborhood on the scene manifold and show that under plausible assumptions the dimensionality is characterized by the spectrum of the spatio-spectral concentration problem. This allows us to improve existing estimates for the dimension in computer graphics using a more insightful derivation and for the first time we obtain optimal representations. The relevance of our results for existing rendering applications is discussed.10.1111/j.1467-8659.2010.01736.x1399-1403