Ray Statistics
The Geometrical Optics interface defines a number of special variables, some of which can only be used during results processing. These variables can be found in the Ray statistics section in the Add/Replace Expression menus.
In the variable names below, gop is the physics interface tag. If multiple instances of the Geometrical Optics interface are different, this tag may differ.
The following variables are defined for each ray:
Ray index gop.pidx. Each ray is assigned a unique index starting from 1 up to the total number of rays. This expression can be used as an input argument to a function. For example, randomnormal(gop.pidx) would sample pseudorandom numbers from a normal distribution with unit variance. The random numbers would be distinct for each ray.
Ray release feature gop.prf. If there are multiple release features in a model, it is useful to visualize which rays correspond to each release feature. Rays from each release feature are assigned a unique integer, starting at 1. This variable can also be used to filter ray trajectories in postprocessing so that only the rays released by a specific feature are shown.
Ray release time gop.prt. Usually, all primary rays are released at t = 0. To allow other release times to be specified, select the Allow multiple release times check box in the physics interface Advanced Settings section.
If the Store ray status data check box is selected in the physics interface Additional Variables section, then the following additional variables are created:
The release time of a given ray (variable name gop.rti). Unlike gop.prt, this works for secondary rays and thus allows for extraction of the time at which a secondary ray was released. This includes reflected rays at material discontinuities and higher diffraction orders at gratings.
Stop time gop.st, when a ray gets absorbed at a boundary or annihilated by the Ray Termination feature.
Final status gop.fs. This indicates the status of a ray at a given point in time. When used during postprocessing, the value always indicates the status of the ray at the last time step. The value is an integer which has one of the following values:
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