Every luminaire contains optical components. The purpose of the optical components is to redirect the light from the light source into the desired light output pattern. The design of such systems is largely done by experienced engineers using known solutions and optimization by trial and error: a design is repeatedly modified until the required output pattern is reached. This is a slow process. Inverse methods, on the other hand, provide an optical design directly for a specified light source and a desired output pattern. Inverse methods can significantly speed up the design process of optical illumination systems, and even provide designs which could realistically never be achieved with trial and error. Due the introduction of LED lighting, there is a renewed interest in inverse methods.