Realtime editable smooth cube-based terrain.

Good morning/afternoon/evening everyone.
I know what I’m looking for has a lot more to it and no terribly simple solution, but I’ve been searching on and off for several months and thought I’d post an inquiry here.

The Question: I’m looking for a plugin or functional example (possibly a tutorial) of a smoothed cube/voxel terrain setup. Preferably cube based but smoothed, similar to this plugin for Unity: /

That said, there are a couple key difference between this request and some others that are on this answers site:

1) I don’t need nor want a terrain generator for this.

2) I don’t want “true” voxels, just a smoothed cube system.

All I’m looking for is the basics, as I want to hand-craft the game world and it’s landmarks, but give the players the freedom to dig/build. What I do need is:

  • cube based terrain with smoothed edges,
  • cubes able to be removed/added in realtime,
  • the smoothed surface/surrounding cubes updated in realtime appropriately,
  • a system to manage loading/unloading.

I have experience with Blueprint, C#, and can learn the syntax for C++ if necessary to accomplish this. I have considered purchasing the above linked Unity plugin, and attempting to reverse-engineer/translate it to C++ to implement in the Unreal Engine, but if there’s a working system out there that I simply don’t know about, that would be preferable, as at the moment I’m the only programmer on this project and have a lot of other tasks to tackle on my list.