01035nas a2200109   4500000000100000000000100001008004100002260007000043100001500113245010700128520069000235       2019                            d  c09/2019bEcole Polytechnique Fédérale de LausanneaLausanne, CH1 aLars Grobe00aPhoton mapping to accelerate daylight simulation with high-resolution, data-driven fenestration models3 aData-driven modelling provides a general means to represent optically complex fenestration in daylight simulation by its Bidirectional Scattering Distribution Function (BSDF). Radiance employs the tensor tree as a compact data structure to store the BSDF at high directional resolution. The application of such models under sunny sky conditions is, however, computationally demanding, since the density of stochastic backward samples must match the BSDF resolution. The bidirectional Photon Map is proposed to rapidly forward-sample the BSDF, starting from the known sun direction. Its exemplary application shows a potential speed-up of ≥ 98 % when compared to backward ray-tracing.