Save to Mesh or Prefab?

I’m working on a voxel editing application (non-game use for a game engine; I know, but people do it with Level editors all the time). Anyways; I have my unique format to save editable copies with (uses the WriteAllBytes() function); but to make the finished art actually usable in games (without long load times out of it parsing the data from the editable version for every object in the scene), I need to be able to output the finished art as a mesh or a prefab.

Any idea how to do this?

Unity is a 3D engine, not specifically a game engine; feel free to make non-games with it. Anyway you can use ObjExporter.

–Eric