The Illuminance calculation module (Lux) aims at providing its users with the raw data of illuminance calculation before any transformation (like Autonomy or other metrics). With this module you can access the illuminance value themselves.
The graphical results present a synthesis of this hour per hour calculation (average or maximum values) for each sensor. It also allows to access the raw data so that you may perform your own calculation for specific metrics or simply to suit your needs.
The calculation is based on the model geometry and its environment, the weather data, the materials used in the model, the period of time upon which performing the calculation and a grid of sensors.
It is basically the root plugin for all sort of calculation that are required in various labels like BREEAM, EN17037, and many others, and accessing the raw data helps you to post-process them.
You can see it as the most basic module for the most advanced users.