Strange result of HB Annual Irradiance

Hi @chris

I made a simple box and wanted to check the annual radiation rate of the roof. However, the result were somehow strange. Please check the screenshot below.

How could the result so strange? Thanks in advance!

It doesn’t really look strange to me given that there’s nothing casting shadows onto that roof surface. So all of the resulting irradiance values are essentially the same and any variation that you are getting is just the stochastic behavior of Radiance. If you are really concerned about a difference of 3 W/m2 out of 1080 W/m2, then you can use some better Radiance parameters and the difference in values across the grid will become smaller.