Cycles Lighting Problem


i am doing a little animation. First the Object is static and i do a camera flyby. Then camera is static and the object will move. In both cases i need a lighting setup what does light up the hard to reach positions.
I tried for hours to get light at that particular spot. No matter if i place planes around it in a 45 degree angle or make a torus as a light emitter. I dont get light to that dam spot.

Please Help

there are so many possible problems that could be causing this, that it would be better if you post your blender.

Sry, forgot to attach blend file. Here it is

In the material of the problem area, you’ve got texture coordinates plugged into the normal of the diffuse BSDF. I could be mistaken, but I don’t think this makes sense. When I remove this connection, the black area goes away (though the whole side is just purple, since the textures are missing). If you want to use a normal map, you can use add->vector->normal map. If you just want it to use the regular normal of the geometry, just don’t plug anything into the normal slot.

If your normals on the mesh are all good and facing outwards and you still have some areas too dark, try adding a bit of ambient occlusion to the world settings. Not too much, just dial it up a little bit. And you may have to adjust other lighting back down when using that effect.