Latent spline lines? Well blended meshes?

I've noticed that on some courses designers seem to have figured out a way to eliminate those latent black spline outlines that seem to plague my course. How is it done? I've tried smoothing and I have brushed in some color but they are still very prevalent.

In addition I've seen some designers really blend their meshes well so that the difference in height is barely noticeable.  I suspect this has something to do with making the meshes thinner but I don't want to mess with that unless it is confirmed and I'm told what the best practices are to achieve that really smooth transition between meshes and elimination of those thin black lines that are a remnant of the outer mesh.

Thank You,

SC 

I have been informed that the black lines on the outer rough are a Dynamic Sky Lighting bug in game,

and has nothing to do with any CF or Unity setting. 

Ahhh...interesting so at some point when I was playing the bug had not arisen yet but now it is a known factor.

Thanks for the information.

SC