Large dynamic world

we are currently working on a online survival game with a single large world (8x8km) and up to 100 players. Also a modular building system is planned so the graph should be updated at runtime. In the game world are few pre-defined villages, the rest is pretty much empty terrain where players can build their bases.
Is there any chance achieve this in this scale?

Thanks in advance

Well… That is hard.
I can at least tell you what you would need to do.

  1. Online world with 100 players => whole world likely needs to be loaded into memory.
  2. 8x8km => large world => recast graphs are really the only option, grid graphs will use way too much memory.
  3. Updated during runtime => If possible, use navmesh cutting (only possible to to add obstacles, not add any new surfaces), otherwise you will have to resort to slower but more flexible full tile recalculations.
  4. Since it is on a server (I assume?), it is less important to keep the framerate stable, which is good.

I would say it is possible, but I would not expect it to come without challenges.