| These are some great observations! Thank you for sharing them with us!! |

Unfortunately, I had hooked up the roughness map wrong in the test...Dohh!! :D However guess it could help someone that experience such issue, that it could be due to their roughness map being wrong.

| How did you reverse the roughness map? |

I just copy pasted the tile map and switch around the black and white tiles. However just to be clear it doesn't mean that the roughness map should always be inverted, it was just in my test. The more rough you want a surface to be, the more white it has to be in the roughness map, so 100% roughness equal white and 0% roughness is black.

However this test did little to solve the noise problem as it seems to come from somewhere else. So I now suspect that its the lights themselves in Poser. So did some more testing, that hopefully ain't flawed :D

This is from the actual scene where im testing. There is one point light placed a little bit underneath the ceiling (Hotpot in the ceiling shows approximately where)

First image have 100% intensity and looks sort of what you would expect with such bright light. There are a little noise but its rendered at 10 Pixel samples.

Second image is at 50% intensity, still looks somewhat ok, however some problems starts to occur i think.

Third image is at 10% intensity, now i think some problems really starts to show. Looking at the ceiling and the floor the light is very dim. However the edge of the window is still very lit and the reflection on the machine to the right looks like its a 9000 Watt light bulb hanging there and doesn't seems to really match the amount of light that is on the floor or even the ceiling to which the light is much closer to.

Fourth image the intensity is 1%, still the window is very bright compared to the intensity of the light and even though the reflection in the machine is not as bright it still seems to bright, i think.

To me it seems as if the light intensity falloff is some what off when it comes to reflections or is it just me?