A proposal for a new generalised rayfile format

The optical design of illumination systems often requires near-field information of the light source. In case ray-tracing methods are used for the design, it is inefficient to consider the detailed internal set-up of the light source, or normally this internal information is not available because it is the essential and confidential know-how of the light source manufacturer. The common used interface to exchange the near-field information is the rayfile interface, which contains basic data for each ray (e.g. starting point coordinates, direction cosines, intensity) in a tabulated form. Unfortunately there exists no standard for the format specification, but a huge variety of slightly different formats, which are not compatible to each other. In our contribution we discuss the state of the art of rayfiles and propose a new generalised format which could serve as a future new standard.