[Please HELP!] Rhino 5 : my modeling looks broken in viewport and v-ray

what’s wrong with my v-ray…?

Hi @yejinnadine
Without seeing the actual file, my first guess would be, that you are really far away from the world origin (0,0,0). If that’s the case, try selecting all of your geometries and move it (so that the building volumes are close to 0,0,0).
HTH, Jakob