A quick question about the PBR_Validation node.

[Yon27655027yxwq]

Why does metallic check use the gray conversion node as 0.333 per channel when transforming from basecolor to reflectance?

[noah5EDA]

I encountered the same confusion

[davescm · Accepted solution]

I suspect the RGB chanels are equally weighted in this node, because the more usual weighting with more bias to green is weighting towards human perception of luminance rather than physical correctness.

You can easily make a copy of the node and then open it and adjust the weightings if you want to try something different. For most practical values, the difference in output appears to be small

Dave

[noah5EDA]

THANK!