[teraflop]

1:1 scale multiplayer world maps have existed for decades, e.g. in Microsoft Flight Simulator.

The difficulty of making a "large" map comes from what you want to simulate and in how much detail, not from how big it is per se.

[chmod775]

This pretty much.

ED has an approximation of the entire milky way in an MMORPG, where you can visit individual planets of around 400 billion star systems. These are obviously "generated" except for maybe a few handcrafted systems like Sol.

The problem really isn't "size".

[shostack]

And sometimes you don't need to simulate. MSFS pulls in live metar data, though previously they used Meteorblue forecast data.