specular troubleshoot

[mark_aldred]

What's going on with my glossiness map here?
Top image is a close-up of a sphere illuminated by a single light. Middle image is what I get if I use a VRayHDRI map with a black and white jpeg in the glossiness slot of a VRayMtl.
The bottom image is the same map in the diffuse slot for reference.

Why am I getting a kind of "find edges" effect?

Edit: Ok, I think I may not be understanding glossiness maps correctly. Can somebody point me to a good explanation please?

[hermit.crab]

Why am I getting a kind of "find edges" effect?

I presume it is because of the texture's anti-aliasing. In those spots, the glossiness is a middle color, meaning it should reflect light that is not exactly direct.

Edit: Ok, I think I may not be understanding glossiness maps correctly. Can somebody point me to a good explanation please?

Have you checked the docs?

[mark_aldred]

Thanks.
I'm still relatively new to PBR rendering. I think I need instead to mask the reflection then use Glossiness to break up the reflection on the reflecting part of the surface? I thought I'd just be able to knock the reflection out with black in the Glossiness map, but it seems not to work that way. I found this link that has what looks to be an explanation of the fringes ..

https://substance3d.adobe.com/tutori...r-guide-part-2

[hermit.crab]

I think I need instead to mask the reflection then use Glossiness to break up the reflection on the reflecting part of the surface? I thought I'd just be able to knock the reflection out with black in the Glossiness map, but it seems not to work that way.

Exactly. A non-glossy reflection is still reflecting based on the chosen reflection color.

I found this link that has what looks to be an explanation of the fringes .

Basically, the anti-aliasing I was referring to (interpolation between the glossy and non-glossy areas, which produces middle colors.

[mark_aldred]

Got it.
Thanks for the help!