Easy Grass Cutter is a powerful tool for cutting grass. All terrain's details can be cutted at runtime with custom shapes and behaviors.

Document | Youtube

By the way, if you have bought uNature and use it as a substitution for unity's terrain, check uNature Cutter

---------------------
Features
---------------------
+ Support cutting all terrain's details at runtime.
+ Support cutting multi terrains.
+ No limit on terrain's size and position.
+ Customized cutting shape.
+ Customized cutting behavior.
+ Optimized code, good performance.
+ Preview in editor, easy to use, drag and drop to play.

4 Demo scenes supplied, have been tested in unity 2017, 2018 and 2019.