In V-Ray 6.1 the V-RayDirt diffuse color viewport display is completely black.
At least V-Ray 5 showed Unocluded colors in the viewport.
Confirmed in V-Ray 61005 and 3ds Max 2023 / 3ds Max 2024 Nightlies/Stable
Hi, thanks for posting. We have this request logged in our system under VMAX-8182. I will add your thread to it and bump the priority.