Optical Research Associates has added an Illumination Module to its LightTools optomechanical modeling software. This feature uses a menu-driven interface to facilitate rapid 3-D solid modeling of illumination systems such as surface-emitting light sources and mechanical constructs. It is equipped with Monte Carlo ray tracing, which allows the user to visualize system performance with photographic-quality graphics that can be zoomed or rotated. The user interface allows designers to compare the performance trade-offs of different design forms. The software can be used to design projection systems, flat-panel displays and other illumination systems.