I know nothing about VRAY, but what comes to mind is that you should check your model for
reversed faces, so that only the front sides of faces are visible.
Many rendering applications struggle with the back sides, either
leaving them invisible, rendering them in an uniform colour or black.
duplicate faces (z-fighting) where two faces are directly on top of
each other
your model location, in relation to the SketchUp model origin. If it
is very far or very large (kilometers/miles)weird things start to
happen with the display.
Thanks for the suggestion of posting a picture.
I uploaded the highest quality rendering that I could get to
Below is a link to an older rendering using sketchup/vray:
(The images were too large to post a picture) https://lmont.egnyte.com/fl/UKV1sQFzSD
I cant figure out what settings he used to produce such a clear model