[lerxst2112]

The concept of a "perception bubble" is not terribly complex for a simple implementation assuming the client knows about entities in a circular region around itself. It can get quite a bit more complicated if you exclude information based on stuff like line of sight, z-height, etc. but there's generally not a ton of benefit to doing that.

The problem you might run into is the client. Usually there's some cooperation needed between client and server to make sure they agree on things like number of entities and having the client be able to request more information from the server if for instance it gets a movement update for an entity it doesn't know about. The client can also be a bit proactive about despawning entities that are out of range without the server specifically telling it to.

I haven't used ShowEQ or MQ2 on a live server for a while, so they may already have a system that does this. It always seemed like the next logical step to combat ShowEQ during the time where they were actively trying to stop it.