If you are using V-Ray for SketchUp, the file extension for render settings is .vropt.
Error: "The specified file is not a valid V-Ray settings file." Vropt File Interior Download Sketchup
Interiors with corners suffer from "darkening." In the Light Cache settings, set Retrace to 2.0 to fix corners without losing the preset's speed. Fix: You downloaded a file for V-Ray 3
Getting Started with V-Ray for SketchUp