Four-dimensional non-linear ray tracing as a visualization tool for gravitational physics

General relativistic ray tracing is presented as a tool for gravitational physics. It is shown how standard three-dimensional ray tracing can be extended to allow for general relativistic visualization. This visualization technique provides images as seen by an observer under the influence of a gravitational field and allows to probe space-time by null geodesics. Moreover, a technique is proposed for visualizing the caustic surfaces generated by a gravitational lens. The suitability of general relativistic ray tracing is demonstrated by means of two examples, namely the visualization of the rigidly rotating disk of dust and the warp drive metric.