Energy loss due to errors is extremely important, and it is imperative that the magnitude of these errors are made as small as possible.  There are several reasons why these errors occur, which are thoroughly discussed in an article entitled How To Locate Geometry Errors. 

If the reported energy loss due to errors is significant, it is sometimes useful to review the propagation of the ray in great detail to locate the probable cause of error.  This can be done via filter strings in the Ray Database Viewer.  The Ray Database Viewer may be opened by selecting "Analysis > Database > Ray Database Viewer" or by pressing the "Rdb" button on the button bar.  In the settings of the Ray Database Viewer, select the previously saved database file from the "File" pull down menu.  Now, the Ray Database settings allow the option to apply a filter.  The filter string, "Z", will only display those rays which have fatal errors.  To apply this filter string, first check the "Apply Filter" box and type the string into the appropriate entry.

The filter may be applied to a small portion of the saved database by adjusting the "First Ray" and "Last Ray" field appropriately.  Or, alternatively, the entire database may be processed if the "Last Ray" is set to the total number of rays launched in the initial ray trace.



In this example, the energy loss due to errors was zero, so not a single ray is displayed in the Ray Database Viewer once the error filter is applied.  However, the filter capability in the Ray Database Viewer is not limited to displaying rays with errors.  Any single filter, or any combination of filters, may be applied to the saved ray database; only those rays which "pass" the test will be displayed for more in-depth analysis.