Optical Research Associates has released its LightTools 6.3 illumination design and analysis software for optical system modeling. It features an alternate optimization engine that supplements the existing one and permits optimization with user-defined variables, merit functions and constraints. It incorporates an expanded LED library that contains mechanical models for LEDs from major manufacturers, including apodization files for accurate far-field modeling of source output, and ray data files for near- and far-field output. The ray data files include color information to model the spatial and angular output characteristics of the source as a function of color. The software includes an enhanced thin-film modeling utility.