Network Proximity Checker

The Network Proximity Checker component controls the visibility of GameObjectsThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
See in Glossary for network clients, based on proximity to players.

With the Network Proximity Checker, a game running on a client doesn’t have information about GameObjects that are not visible. This has two main benefits: it reduces the amount of data sent across the network, and it makes your game more secure against hacking.

This component relies on physics to calculate visibility, so the GameObject must also have a colliderAn invisible shape that is used to handle physical collisions for an object. A collider doesn’t need to be exactly the same shape as the object’s mesh - a rough approximation is often more efficient and indistinguishable in gameplay. More info
See in Glossary component on it.

A GameObject with a Network Proximity Checker component must also have a Network Identity component. When you create a Network Proximity Checker component on a GameObject, Unity also creates a Network Identity component on that GameObject if it does not already have one.