I'm having a problem using a specular material with displacement - looks like a bug to me.
The problem is in both Octane Standalone 2.25 and 3.0 alpha 4. As soon as a I add displacement to my specular material the scattering goes completely out of whack and looks very wrong. Adjusting the Scattering color and scale don't help, and neither did adjusting the displacement values. I'm using a 16 bit TIFF displacement map exported from zbrush. I also tried a couple of other image formats in the displacement texture input as a test but get similar major problems no matter what.
I tried looking around online for a fix with no luck. I saw an older post that mentioned a possible fix of plugging the skin material into both inputs of a mix material and using displacement on the mix material, but this didn't help or change anything.
Here are some screencaps showing the problem, showing what the material looks like in Octane 2.25 and 3.0 alpha before displacement and after displacement.
Anybody have any insight into this?