This one also uses InfMap, but unlike the 1:1 Multiverse, which is pretty much barren at the moment, it uses InfMap's basis to recreate our solar system. That's probably a little hard to grasp in abstract, but you can see that in effect in one of Alexandrovich's other mods, the 1:1 Solar System.

That's how it keeps its infinite illusion going. Or, to boil it down, what makes InfMap interesting isn't that it changes the map, but that it changes the objects within the map. InfMap handles that by changing the properties of map objects in such a way (and I confess I'm operating at the boundaries of my understanding here) that they become invisible and un-collidable once you hit that boundary transition, but still appear visible when you look back at where you came from, maintaining the illusion of forward progress.

Obviously, if you leave a big cube smack-dab in the centre of your map, the illusion of infinity will end up broken as soon as you hit the edge and come in from the other side, seeing a cube that was behind you appear in front of you. That'd be a huge letdown if that was the whole trick, but it's in dealing with objects within the map that InfMap gets properly clever. You can actually see this working in 1:1 Multiverse just by firing a rocket: it'll exit the top of the map before jetting past you from below, a process it will repeat indefinitely. But in essence, InfMap works like this: once you hit the boundary wall in a Source map, you get teleported to the other side, Portal-style.

Youtube videos garry's mod