Today the development of modern complex automotive lighting systems is only possible with the aid of computer technology. Therefore the CAL (Computer Aided Lighting) system HELIOS was developed for own purposes. The simulation of any optical device is a main part of this program package.The light source model plays an important role in this simulation process. In general a simple model of a cylindrical light source is used, which allows a fast simulation. But sometimes it is necessary to consider more details of the lamp, because they affect important parts of the resulting light distribution. This is possible with an advanced lightsource model, which allows to build lamps like a H7 bulb with complex details.