The engine was specifically made for procedural world generation and planetary scale range, and as such you can't really separate the generator and the engine and put the generator into a generic 3D engine (with the same performance).
Moreover I don't think any engine can just simply replace its rendering part, like Mizuchi tries to indicate with those fancy blocks. OT renderer is physically based as well, but it's limited by the amount of data needed for the whole world rendering and it has to do some compromises. Even if it was possible to simply replace the material renderer, the result won't be the same as shown there, with current hardware generation.