I was looking for an answer to this question and I stumbled upon this old post:
I would like to use RADIANCE in meters. According to what Roland_Schregle said, there is no particular care I have to put, right?
If, for example, my test room and the objects it contains come from a 3D modeling software where they were modeled in meters and my ies files are also expressed in meters there shouldn’t be any problems since the radiance and irradiance in RADIANCE are expressed in meters^2.
Would this be right?