A Framework for Collaborative Augmented Reality Applications | I3D 2025

Figure: Real-time AR drawing synchronization between two mobile devices using our framework

Overview

This repository presents a framework designed to streamline the deployment and configuration of colocated collaborative augmented reality (AR) experiences for mobile devices (currently supporting ARCore-compatible devices). The solution employs a centralized client-server architecture, where a dedicated local server (PC) manages real-time data communication and synchronization across connected devices. This approach eliminates reliance on cloud anchor services or third-party platforms, which often impose restrictive limitations.

Perfect for:

• Prototyping multi-user AR experiences
• Collaborative projects
• AR education tools

🧩 Project Components

Folder	Purpose	What You'll Find There
Server/	Contains the complete architecture and technical configuration for the local server, including all necessary components and operational processes	Server code, database setup
App/	Includes the mobile application implementation that connects to and interacts with the server framework	Unity project, App setup

🛠️ Setup Guide

Before You Begin

You'll need:

✔ Computer: Windows/Mac/Linux with:

• Node.js v22.12.0 (installation guide)
• MongoDB 8.0.4 (installation guide)

✔ Phones: 2+ Android devices with:

• ARCore support (compatibility list)
• Developer mode enabled

✔ Refer to SERVER.md and APP.md for setup instructions.

Step 1: Get the Code

1. Clone the repository (download the project):

git clone https://github.com/MurilloLog/CollabAR.git

2. Navigate into the project folder:

cd CollabAR

Step 2: Launch the Server

1. Open two terminal windows and navigate both to the Server/ folder:

cd Server

2. In first terminal (Database-MongoDB)

• Start MongoDB

  mongod

  ✅ Successful confirmation

  Wait for the log message: [initandlisten] Waiting for connections.

3. In the second Terminal (Application - Node.js)

• Install dependencies (first time only):

npm install

• Start the server:

npm start

✅ Successful confirmation

Look for the message: "Wating for connections..."

⚠️ Important Notes:

• Do not close either terminal window while using the application.

• Closing the first terminal (mongod) will shut down the database.

• Closing the second terminal (npm start) will stop the server.

• To stop the servers safely: Press Ctrl + C in each terminal to terminate processes gracefully.

🎨 Using the App

1. Connect Devices:

• Positioning: Point all device cameras at the same flat surface (table/floor).
• Connection:
  • Enter the server’s IP:PORT address manually (found in SERVER.md).
  • Tap "Join" to sync devices.
  • Wait for all players
• Verification:
  • Check terminal logs for "Client [IP] connected" confirmation

2. Start Drawing:

• Choose colors from the palette in your app
• Draw in the air – your strokes appear when you finish - others will see your drawings
• Walk around - drawings stay anchored to their physical location

🔍 System Verification

To confirm the system is operating correctly:

1. Check the server terminal (where you ran npm start).
2. Look for these key log messages:

• ✅ "Connecting to MongoDB..."
• ✅ "Successful connection..."
• ✅ "Waiting for connections..."

❓ Common Questions

Q: Why do devices need to be close together?

A: Devices need to be close to share the same AR space and use a common reference point from the starting position for accurate synchronization

Q: Can I use iPhones?

A: Currently Android-only (ARCore requirement), but iOS support could be added.

Q: How many users can join simultaneously?

A. The system supports theoretically unlimited connections, but practical performance depends on:

• The PC specifications (CPU/RAM)
• Network conditions (latency and stability)
• Drawing complexity (size/detail of shared AR content)

Please kindly cite our paper as:

@inproceedings{10.1145/3722564.3728390,
author = {Murillo Gutierrez, Gustavo Adolfo and Jin, Rong and Ramirez Paredes, Juan Pablo Ignacio and Hernandez Belmonte, Uriel Haile},
title = {A Framework for Collaborative Augmented Reality Applications},
year = {2025},
isbn = {9798400718335},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/3722564.3728390},
doi = {10.1145/3722564.3728390},
series = {I3D Companion '25}
}