[TaoLibra]

Neither a Dyson Sphere nor a Ringworld is scientifically plausible. The volume of raw material necessary to build even a small Ringworld (let alone a Dyson Sphere) would require that the builders plunder the complete mass of hundreds, possibly thousands of whole star systems — and then transport all of that mass to the building location, too. Even if that were physically possible, they'd obviously want to take that mass from the nearest star systems to where they were building it — so when they were done, there wouldn't be a single moon, planet, or even another star for thousands of light years in every direction. That Dyson Sphere or Ringworld would be the only object on the entire map.

The only other (ahem) "plausible" way to acquire the necessary mass would be if the builders had direct energy-to-matter conversion — but if they were that powerful, they wouldn't need to build such a thing.

Of course, plausibility doesn't necessarily matter in a game any more than it does in Science Fiction novels; but neither a Dyson Sphere nor a Ringworld could be portrayed correctly in the game anyway, because of the monstrous scale of such objects. It would have to enclose its star, not orbit it, which simply cannot be done in the game.