@JasonBooth revealed his upcoming asset MicroVerse, a non-destructive, real time environment creation system: It's exciting and super fast with lots of features. You can drag around stamps, have them stack on top of each other. It even includes a spline based path creation system. Supports terrain trees and terrain details. And many more. Awesome!
I toyed around with the beta. Here's moving a Unity Terrain Stamp: Blending: And this is a single stamp duplicated, scaled and rotated multiple times: The speed is most impressive.
Here's more features of Genesis for MicroVerse. It contains tools around MicroVerse. Examples: Randomize terrain heightmap: Place terrains as grid to get an overview: Shuffle multiple terrains, random placement and layering. Basically you drag in heightmaps and have them placed and layered within constraints you can specify. Here's with all current free stamps of my free StampIT! Examples: You can have eg the terrain features like Canyon, Volcano and Crater mixed within and still visible depending on your settings.
Toyed around again with MicroVerse today. It's such a huge time saver compared to the built-in Terrain Tools:
It does! For every scene that needs to be 'Microverse aware', just add an MV GameObject to each scene and then add the terrains to the Explicit Terrains list. Microverse figures out the rest. Works great!