---
title: Iris Replication System
source: https://dev.epicgames.com/documentation/en-us/unreal-engine/introduction-to-iris-in-unreal-engine
version: Unreal Engine 5.8 Documentation
fetched: 2026-10-11
note: 原文摘录（英文），供 wiki 引用；非全文
---

# Iris Replication System

(另含 iris-replication-system-in-unreal-engine)
- Experimental: use caution when shipping. Opt-in, works alongside existing replication. Builds on Fortnite Battle Royale (up to 100 players per server instance): larger worlds, higher player counts, lower server costs.
- Existing replicated properties and RPCs compatible with minor modification; opting in requires new engine APIs. Iris expects clients (game code) to notify the replication system when changes are made.
- Enable: Iris plugin in .uproject; SetupIrisSupport(Target) in Build.cs; bUseIris = true in Target.cs; DefaultEngine.ini net.SubObjects.DefaultUseSubObjectReplicationList=1, net.Iris.UseIrisReplication=1 (optional push model). Runtime: -UseIrisReplication=1/0.
- Improvements: removing antipatterns; concurrency by separating replication and game thread data; sharing workloads across objects and connections. Keeps full copy of all replicated state in quantized form.
- Components: Replication System (state copy, per-connection tracking, filtering, prioritization, serialization), Replication Bridge, Net Object, Replication State, Replication State Descriptor, Replication Protocol (per type), Replication Fragment, Replication Instance Protocol, Net Handle (returned by BeginReplication).
- Flow: registration → pre-send update (poll if legacy mode, quantize dirty state, update filtering/prioritization) → send update (data streams; schedule by priority, sort by priority and dependencies) → receiver deserializes, instantiates, pushes to game.