I have a normal map on a simple flat plane. It is catching the light opposite of the sun lamp which is illuminating it. In other words, the plane is in full sun when the sun lamp is pointing straight up away from the plane and the plane is dark when the sun lamp is pointing straight down at it.
I have tried flipping normals, recalculating them, rotating and flipping UV maps, experimenting with normal map node settings, but nothing works.
Searching through some of the posts here, this looks like an old problem going back years with no solution.
Thank you Very Much, Salai_V_V1. That was quite a trick and I never would have found it by myself. To get it to work, I needed the FAC to be -1, but it is now working perfectly. Thanks again.
It happens becuase normal maps come in two flavors – OpenGL and DirectX. I assume blender interprets normal maps based on OpenGL where as DirectX normal maps are geared towards game engines. Both have their normal maps inverted.
And as far as I know, there’s no way to know for sure which flavor your maps come in.
