World regeneration relies on new information exported by the world builder when generating a world, a distance field which encodes the distance to the surface of the world before things like trees are inserted.
As processes in the world at runtime cause changes to the world a distance ordered list of deltas is maintained to return the chunk back to its original state.
Chunks with regeneration required are visited stochastically to move the chunk back towards its original state weighted by things like last time the vicinity of the chunk (50m or so) was left vacant, or when the chunk was last modified.
But what would happen if you beaconed an entire mountain side… and then painstakingly removed EVERY SINGLE BLOCK, removing your beacon afterwards allowing the world regeneration to take over and return the mountainside to its original state?
maybe something like this? (initial prototype of world regeneration, parameters not tweaked in any way yet)
@olliepurkiss, help me