The Terrain Tools preview package provides additional functionality on top of Unity’s built-in Terrain tools. It includes more advanced features such as Erosion, sculpting tools, and Brush Mask Filters. It also contains the Terrain Toolbox, which lets you create new Terrain from preset files or imported heightmaps, batch change settings on multiple Terrain tiles, and import/export splatmaps and heightmaps.
This add-on toolset is suitable if you require more control over the appearance of your Terrain, and wish to streamline Terrain workflows. It’s also useful when you want to make more complex-looking Terrain, or author Terrain Texture data in external tools such as Houdini and World Machine.
For more information about how to install and use the Terrain Tools package, see the Terrain Tools documentation.