Modelling Light Scattering in the Context of Freeform Optical Design Simon Kronberg, Martijn J.H. Anthonissen, Jan H.M. ten Thije Boonkkamp and Wilbert L. IJzerman EPJ Web Conf., 238 (2020) 02003 Published online: 20 August 2020 DOI: 10.1051/epjconf/202023802003