Make Principled BSDF Respect The IOR And Transmission Properly When No Light Is Absorbed.

(Cycles)

As far as I'm aware, a colour of R1 G1 B1 in the base colour of the principled BSDF means that the material absorbs no light. With an IOR of 1, the material should reflect no light and bend no light. So, what should be left is the subsurface scattering. If you turn the transmission all the way to 1, the material should become completely invisible and undetectable, however, in Blender 4.2, if you have a roughness of 1, material will still show.

There is no internal structure for light to scatter in. There is no surface absorption or reflection.

But there is still a soft-looking partially visible material left over. Idk if this is a bug or just a feature not yet implemented, but I'd love to see it work in a more physically accurate way. If I'm being stupid and missing something obvious, let me know.