at sky type you choose. See images below.
A Tregenza sky discretizes the skydome into 145 patches to simplify the calculation process. This skydome approximates the smoother Perez sky shown below. Both the Tregenza 145-patch sky and the Perez sky use climate data to create realistic skies that react to hourly solar and weather data. So there may be some differences between the two runs. Also, every unique run will have some error based on how the calc process works and what your presets are.
Tregenza 145-patch sky-…