It can't get any smoother :)

With a mindslicing TerrainBlock tricky extension the tiles are now using the normals as if it were a big normal TerrainBlock, not several ones - one per ground tile exactly.

In our cube based architecture the tiles have to be generated one by one, so normals were missing from the ground tiles because the separated TerrainBlock meshes cannot calculate with the vertex positions of the neighbouring tiles. Now the trick is - use the full RenderedArea's cube elements to get neighbor opposite/adjacent Cube's already present height data, create a one size bigger (9 points 3x3) heightmap and build vertices/normals from that heightmap for the original 4 cornered (2x2) heightmap's normal buffer. Uh, crazy to write down, but it's working. The shot shows how gooood. :) And it's not slow either luckily! :)