Hi, Addons like EasyRoads, RAM, Mapmagic, Gaia and similar are all modifying terrain data. While some of them alter the basic structure of the terrain some just put small adjustments on top. But this requires all authors to either warn users that this has destructive effects or implement hackish backup functionality because other/manual alterations could potentially be destroyed along the way. Akin to the new TerrainLayers for texture i can imagine having Deformation Layers for height data. This would allow addons to work nondestructively and also have a clear position or purpose in the layer stack. For example addons like Gaia and the like would work on the base layer that defines the overall shape while addons like EasyRoads work on an upper layer thus not interfere with each other. This may also open up options for layer specific queries, blend operations, modular, predefined terrain variations etc. @ Unity Terrain Team, If that sounds doable, please consider adding it, it would be a win for everyone.