Strange horizontal stripe on a surface with a Cycles material applied I am getting a strange horizontal stripe with rendering a curved surface with a wooden material applied by using the Cycles renderer. The picture below basically tells it all:



I've uploaded the Blender model here:
The Blender model for reproducing the problem

As far as I can tell, there's nothing wrong neither with normals nor with the geometry itself at the location where the stripe appears. Nor does it seem to be a texture mapping issue since if I switch to the "textured" display in the main editor pane, the stripe goes away and I can see the texture mapped exactly the way I want.

I've also played a bit with the node editor for the material to check to see if there are certain nodes that could contribute to this strange effect, but to no avail :(

Hopefully someone experienced from the community could give me a hint what's going on since I seem to be out of further ideas to try.

Thanks!
I suggest that you turn off your current [sun] lamp for rendering.
Add a new [plane] with emission material and use this as a light source.
The visibility settings of the new [plane] should have camera visibility off depending on the placement.

All these actions should take 3 minutes or less when you have practiced them.