For more detail this asset from the Unity Asset Store: Click Here
This is a paid asset, but now you can download Terrain Tile Editor for FREE, Please keep in mind this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Terrain Tile Editor v1.2.1
“If possible, please buy the package to support the developer”
Triangle Studios’ Terrain Tile Editor package provides an easy way to use tile sets in combination with Unity terrains. Simply paint tiles onto the Unity Terrain, and maintain all the flexibility you normally would when designing a map.
Terrain Tile Editor will enable you to layer up to 8 individual tile maps. Tile sets are created using the Warcraft 3 standard. This means that lots of materials have already been created by the community and can be imported in your project right away!
