Black spots on diffuse material in certain area of scene.

Hi, I have this huge scene with I currently have not yet any special materials. Only diffuse everywhere. Then I have in this scene one little spot where every object starts having black spots with no reason I can find out. Can anybody help me to understand what’s going on here? It has nothing to do with the normals, because I can duplicate object from some other place and move it to that area, it also starts to have these black spots.

I’m also tried to rotate the sun lamp etc, but it did not help either.

Add an HDRI background and see if they go away, but my guess is that there is no light source within 4 bounces for diffuse and that is causing it to render black.

Also, names, omg name your stuff please!

I don’t know what it was, but I “fixed” it by scaling only little bit the model and now it works again. HDRI bg did not help with it.

It is very likely that you had some duplicate faces at the same exact place.

That was also my first idea, but when I checked it, it was not the answer. But it was something with this particular object, because just scaling it fixed it. It was also possible to replicate the problem by just adding some random object to this same place. But now I cannot anymore do it, since the problem disappeared.

Those spots were visible only in render mode.