Commonwealth Online

Commonwealth Online is an experimental research project exploring the possibility of adding basic multiplayer-style networking to Fallout 4.

The goal is not to create a full co-op campaign mod immediately. The first goal is much smaller:

Two Fallout 4 clients in a controlled test environment, with each player visible as a synced remote actor.

This project is currently in the research and prototype stage.

Project Goals

First Prototype

• Load a native Fallout 4 plugin through F4SE
• Connect to a local test server
• Send local player position data
• Receive remote player transform data
• Represent another connected player using a placeholder actor
• Restrict all testing to a custom test cell

Long-Term Ideas

• Basic LAN multiplayer test mode
• Remote player movement sync
• Basic animation state sync
• Basic chat or debug messages
• Host-controlled test cell
• Simple co-op combat arena

Non-Goals

This project is not currently trying to support:

• Full Fallout 4 campaign co-op
• Quest synchronization
• Settlement synchronization
• Full NPC/world state synchronization
• VATS synchronization
• Public server/MMO gameplay
• Compatibility with large modlists

Those systems are extremely complex and are outside the scope of the first prototype.

Repository Layout

docs/             Project documentation and research notes
plugin/           Native F4SE/CommonLibF4 plugin work
creation-kit/     Creation Kit plugin files, Papyrus scripts, and test cell notes
server/           External multiplayer test server
protocol/         Network packet design and sync documentation
tools/            Helper scripts and utilities
test-data/        Example packets and test data
screenshots/      Development screenshots

Requirements

This project is expected to require:

• Fallout 4 on PC
• Fallout 4 Script Extender, F4SE
• Fallout 4 Creation Kit
• Visual Studio 2022 or newer
• CMake or another supported C++ build system
• A CommonLibF4-based plugin template
• Git
• A clean Fallout 4 test profile

Recommended Development Setup

Use a separate Fallout 4 installation or a dedicated modding profile for testing.

Recommended setup:

Fallout 4
F4SE
Creation Kit
Mod Organizer 2 or Vortex
Visual Studio
Git

Use a clean test save and avoid testing with a full personal modlist.

Legal Notice

This repository does not include Fallout 4 game files, Bethesda assets, F4SE binaries, or any proprietary game code.

Users are responsible for owning Fallout 4 and installing required external tools themselves.

Status

Current status:

Research phase
Repository structure setup
Protocol planning
No playable multiplayer build yet

License

To be decided.