I have a simple plane I exported from Maya. I put a normal map on it and am trying to light it with a single light. I see the light influence at the top as expected. However, no matter what I do, there is a strange artifact in the middle of the plane. I get this with the standard shader. So what is setup wrong that is doing this? I have attached a image showing the issue.
My guess is you have a vertex with its normal going a funny direction. Try changing the model asset’s normals to “calculate” instead of “import” and see if you still have a problem.
That was my first guess and I did this. No dice. I even just replaced my maya polygon with a Unity Quad and it did the same thing. I’ve tried a directional light. A point light. They all do the same thing.