What criteria do we use for that? Is it just proximity, a bubble or streaming window around you where anything within it is visible to you and anything outside it is not loaded into memory?
TL;DRStreaming isn't a fixed-distance bubble but depends on how large an object would appear, so big things like a city stream out far away and small ships much closer, all decided by the servers.
Pretty much, yeah. It's not exactly a hard bubble. It's not a defined distance. It's actually the size the object will appear to you if you were to look at it. So an object that's twice as big, you will see it the same size as an object that's half as big, twice as far away. See what I mean? So a planet will stream out... Well, no, that's a bad example. Levski will stream out very far away, but a small spaceship like the Gladius will stream out much closer.
So the system's going to know that if you're approaching Levski, to bring Levski in at this far away, but if it's a Starfarer, to bring the Starfarer in at this far away, and if it's a Hornet, to bring the Hornet in at this far away. And at the end, when all is said and done, is that something handled by the servers or by the clients?
That's handled entirely by the servers.