SurfaceLuminance similiar in C4D?

[pixelmonk]

is there a way to recreate surfaceluminance node (maya) in C4D? I'm trying to integrate day/night earth maps on a globe, using a distant light. I know surfaceluminance is a maya node, but it works with Arnold. I wondered if there was an all-arnold approach?

[Stephen.Blair]

MtoA converts surfaceLuminance to an all-Arnold shader tree.
If you export a shader that uses surfaceLuminance, you'll see this instead of "surfaceLuminace"

rgb_to_float
{
 name surfaceLuminance2
 input surfaceLuminance2/utility
 mode "luminance"
}

utility
{
 name surfaceLuminance2/utility
 shade_mode "lambert"
 color 4.48571444 4.48571444 4.48571444
}

[pixelmonk]

works great. .thanks! I also forgot i could export the shader from Maya to C4D.