Path tracing renders objects black

I’ve built a scene and started experimenting with path tracing. Problem is, beside the landscape that i’ve properly imported that renders corectly, i’ve also imported 4 custom meshes that represent other parts of the landscape that render black, is there a fix besides making the other parts separated landscapes and rejoining them togheter?Also, how can i influence the light using path tracing ? I could’nt change the color and the volumetric fog disappears and deletes my god rays and the entire atmosphere.

Do you have a post processing volume in the level? You can influence how path tracer works in the sub menu for path tracing there.