The Unity Editor has a built-in Terrain system and an optional Terrain Tools package.
The Terrain Tools package adds functionality to Unity’s built-in Terrain tools. It includes more advanced features such as Erosion, Noise, 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 and export splatmaps and heightmaps.
Use the package to:
To install the package: