-Unpack map you want to edit
-find the i3d file of this map and open it by notepad++ or normal notepad
-copy line that is below instruction 
-find the exact same line in your i3d file by pressing CTRL+F and typing "DisplacementLayer"
-paste and replace line that you copied before and make sure you don't have two of this lines in your file
-save i3d and pack your map again into zip folder

Enjoy better ground system :D


 <DisplacementLayer name="terrainDisplacement" size="16384" tileSize="16" numChannels="6" cellSize="8" viewDistance="75" blendOutDistance="5" maxHeight="0.7" densityMapShaderNames="terrainDisplacementMap"/>