Transmittance value tolerance issue with Radiance Glass Material 3 component

I’m inputting a value of 0.4 to the Transmittance of the radGlassMat3 component, but the result is 0.436219534254 for some reason.

I tried coercing the input to take a float type hint but that doesn’t change anything, neither does changing precision settings in the Rhino file itself.

Any ideas why this is?


Search for transmittance vs transmissivity. Your input value is transmittance (0.4) but Radiance needs the transmissivity value (0.4362195…).