The Calculation Menu provides some control over the radiosity calculations from within the viewer environment. Here you have the ability to Pause/Resume, Cancel or conclude the radiosity calculation and proceed to the calculation of individual illuminance points (Next). You can also begin the calculation again using the Calculate option (F12) should settings change (see Settings below).

These options apply to only the environment that has been loaded into the viewer. The calculation viewer is not refreshed with a revised environment if you leave it open and then make changes in Revit.

Settings...

The Settings selection provides access to the same radiosity settings as seen in the master program Settings dialog.

Here you can change the radiosity Stopping Criterion, adjust the Adaptive Subdivision parameters, enable Secondary Sources or modify the mesh of the selected environment. Details for all of these items can be found in the Master Program Settings area.

Summary...

The Calculation Summary is a detailed breakdown of statistics associated with the calculation of the currently loaded environment. This includes: elapsed times in hours, minutes, decimal seconds for the various portions of the calculations, a Radiosity Summary showing various settings and calculation process accounting, and an Environment Summary describing maximum computed Luminance and Illuminance and various radiosity mesh parameters.

While not essential information for most users, you may find it useful in the event of problems and communication with Lighting Analysts.