On my model i have a tangent space normal map generated in Zbrush (properly set up yes).
Problem appears when lighting it. 1 direct lightwith raytraced shadows, 1 omni fill light w/no shadows, mental ray, no indirect illumination. Shader is a standard blinn. (Got the same problem with a well setup skin SSS which is my intended shader for final render.)
As you can see, along the terminator of the light, most prominently at the eyebrow, a nasty edge appears on the shadow. I've tried tweaking the shadow/light settings in all the ways i can think of.
This is the model without any maps. Shadows are nice and soft.
It would also seem that the shadow edge appears along the nearest normals along the terminator.
Searched the web for a long time, but no one seems to have any answers, or even the same problem. The problem appears on other models set up in a fresh scene too.
So, anyone have any ideas as to what i am missing?