Pretty self explanatory here, If i render the vray dirt using reverse normals and use in the diffuse, I get a nice smooth gradient from white to black across the edges of my model, perfect.
However if I use it in the bump, the bump becomes very jagged an inconsistent. This isn’t usable and not what I expected. Extra samples make no difference.
Using V-Ray core version is 1.90.03 for windows 7 on Maya 2011.
It won’t work for the time being; if you want a rounded corners feature, just add the V-Ray “Round edges” attributes to the shading group of your material.