Note: The Ray Tracing study step is similar to the Time Dependent study step, but has a different default time step size and termination criteria. For this study, the maximum time step is specified in terms of the maximum path length which can be easily estimated from the geometry dimensions. It should also be noted that while only two time steps are specified (corresponding to optical path lengths of 0 and 200 mm), the study does of course refract the rays at all material discontinuities at intermediate times, even when these do not match up with any of the specified output times. The ray tracing algorithm can apply a very large number of reflections and refractions between consecutive time steps or optical path length intervals taken by the solver. The maximum number of interactions per ray, per time step is 1000 by default but can be adjusted in the physics interface Advanced Settings.