I'm not quite sure what you meant by: The effect I'm going for is to have the exposure set correctly for the indoor lights. I'm taking that you mean intensity because when I see `exposure`, I'm thinking the actual setting on the Maya camera via one of MR's exposure nodes. I don't really use the blackbody, I thought it was the same as the mib_cie but I think the cie looks better even though it's temperature is bit more limited but it doesn't really bother me. When it comes to intensity however, that's where the real headache starts because Maya light intensity doesn't correspond to any real world units so you're left to pretty much eyeball it til it looks good. It would be great to enter intensity values with some kind of mathematical accuracy(I've given up hope of it also being user friendly) and then fiddle with the camera's exposure to get light balance you want but nope!(well, at least not that I know of) Also, quadratic decay is closer to real world light fall off than linear and yes you can plug a blackbody into the env channel of the portal light node.