Migrating from Flat to Spherical Grids
Legacy
Given that VR began in the era before neural networking, beowulf clusters, and multithreaded processing, it is unsurprising that VR spaces have always been rather limited in the amount of virtual "real estate" represented in a given simulator, because a single sim ran on a single server, so scaling was always an issue.
Even with a large grid like Second Life, it is an asset and server centered architecture, where a single region of 256x256 meters of virtual land is operated on a single server core. Even when you can run multiple sims on a single core, they were still separate regions that may or may not be virtually adjacent on the grid.
Because of this architecture, in order to cross from one region to another, necessitated the users viewer essentially log out of one regions server and into the server of the adjacent region one is entering, along with all assets that the users avatar is wearing and/or sat upon (in the case of moving vehicles). While the system is designed to make this visually as seamless as possible, it still results in a considerable lag of several seconds that breaks the sense of immersion and can even result in the users viewer crashing.
Other VW platforms have different region sizes. Decentraland, for instance, treats every 16x16 square meter parcel of NFT LAND as its own entity, unless one person owns adjacent parcels and can have them load together. Sansar promises 4kmx4km region sizes, but non-gridded, and they are all tightly curated and very empty.
Var-regions and Megaworlds
In order to resolve this issue for most purposes, given the relatively small size of a standard region, in opensim, var-regions were invented in Opensim. This technology allows for a wide range of region sizes, from the legacy 1 sim 256x256 up to a typical maximum of 1kmx1km (8x8 or 64 SL sized regions in one), however experiments by the US Army's MOSES program on the PhysX enabled platform had regions as large as 32x32 kilometers for simulated exercises.
