Landscape Builder is a professional editor extension for Unity
that allows users to create realistic,
detailed and consistent landscapes completely from scratch.
It can generate topography, texture landscapes and populate them with trees, grass and meshes. It can control scene lighting, weather, and day/night cycles.
Designed from the ground up to be able to create an almost infinite variety of real-world results, it nonetheless is intuitive and easy to use so that
you don’t have to be a genius to achieve those results.
When using Landscape Builder, you won’t have issues with compatibility (as it uses standard Unity terrains), no special plugins or shaders are needed to
get good results and those very results can be achieved within half an hour or less! Above all, Landscape Builder just works.
You can get Landscape Builder from the Unity Asset Store here