HELIOS is a program for calculation, simulation and analysis of lighting problems expecially designed for car lighting technologies.Base is an “experiment” in which optical elements and theire features are described. Example: The reflector is defind by CAD-data and the surface is reflective. The result of simulation will be a light distribution. The performance has to be analysed.The LDE gives us the possibility to analyse light distribution strategies before calculation of the reflector surface itself. It is a“virtual light world”.This reduces developing time and costs and gives a help to find the best technical solution for complex illumination problems.