The 1828-mat-vray material is a "light eater." Because it is so dark, it absorbs most photons. You must adjust your lighting strategy accordingly.
Don’t be afraid to add a "Dirt" map or a "Curvature" map within the V-Ray Asset Editor to your imported material. This adds subtle imperfections that make a scene look lived-in. 1828-mat-vray for sketchup