Realtime rendering with pre-baked lighting cannot be compared to raytraced rendering.
Something that looks ok in Vray doesn’t have to look good in UE4, too.
UE4 by default is using textures to store pre-baked light and shadows.
This so called lightmap is created based on a second UV layer that can have a completly different layout
then the first one used for the texture of the mesh.
These lightmap UV layouts follow a different set of rules then the UV Layout for the mesh texture.