Black stains/pixels render I am having an issue with a rendering. I am trying to render a outside architecture scene with a sky texture (nishita)
For some reasons, there are some black stains/pixel in some random areas of the render...
I'm using blender 2.90.1
Here is the file :

Any thought ? :D

Thanks
Valentin
Be careful with the musgrave texture. Its values are not constrained to the [0...1] range, which can result in negative values. The roughness is not supposed to get negative values, thus the black artifacts.
An easy fix is to add a clamp node, which will constrain the result between 0 and 1.