Table of Contents
The Untold Engine strives to be a stable, performant, and developer-friendly 3D engine that empowers creativity, removes friction, and makes game development feel effortless for Apple developers
The Untold Engine is an open-source 3D game engine under active development, designed for macOS and iOS platforms. Written in Swift and powered by Metal, its goal is to simplify game creation with a clean, intuitive API. While the engine already supports many core systems like rendering, physics, and animation, there’s still much to build and improve.
Creator & Lead Developer: Harold Serrano
Click on image to play video:
- Cross-Platform Support: Runs on macOS, iOS, and visionOS using a unified Swift + Metal codebase.
- Modern Renderer: Built on Metal with support for PBR materials, IBL, post-processing effects, and efficient GPU resource management.
- Entity–Component–System (ECS): Lightweight ECS architecture for organizing game logic and behaviors cleanly.
- Scene Graph: Hierarchical transformation system for managing parent–child relationships between entities.
- Physics System: Includes Euler integration, motion systems, and component-based extensibility for collisions and constraints.
- Animation System: Supports skeletal animations and reusable animation clips.
- Input System: Unified keyboard, mouse, and touch input handling (with controller support planned).
- Gaussian Splat Rendering: Native support for rendering 3D Gaussian Splats with Metal, enabling photorealistic scene reconstruction and novel view synthesis.
- Untold Editor Integration: Optional visual editor for managing assets, entities, and scenes.
- Swift Package Manager (SPM): Fully modular — integrate it easily into your own Xcode or Swift projects.
- Open Source & Extensible: Licensed under LGPL-3.0, encouraging collaboration and custom extensions.
The Untold Engine is a work in progress, with ambitious goals to:
- Extend the physics and collision system.
- Add advanced lighting and reflections.
- Expand XR and input support for visionOS.
- Improve workflow between the engine, editor, and asset pipeline.
The Untold Engine project consists of multiple components designed for different audiences:
- What it is: Standalone application (DMG download)
- Includes: Visual editor + scripting + full engine + all dependencies
- Target audience: Game developers who want to create games
- Get it: Download releases
- No coding/building required — just install and start creating
- What it is: Core engine repository (this repo)
- Contains: Rendering, physics, ECS, animation, input systems
- Target audience: Developers contributing to the engine core
- Get it: Clone UntoldEngine
- Purpose: Improve or extend the engine's fundamental systems
- What it is: Editor interface repository
- Contains: Visual editing tools, UI, asset management
- Target audience: Developers contributing to the editor
- Get it: Clone UntoldEditor
- Purpose: Improve the editor interface and workflows
Quick guide:
- Making games? → Download Untold Engine Studio
- Contributing to engine core? → Clone Untold Engine
- Contributing to editor? → Clone Untold Editor
For comprehensive guides and API documentation, visit:
👉 Untold Engine Docs
You'll find:
- Game developers: Tutorials on using Untold Engine Studio
- Contributors: Architecture guides and API references
- Installation & setup for both users and developers
- How-to guides for common tasks
⚡ New to game development with Untold Engine? Download Untold Engine Studio and check out the Getting Started guide.
Want to make games? Download Untold Engine Studio — a complete standalone application that includes:
- ✅ Visual editor with scripting support
- ✅ Full Untold Engine integration
- ✅ Asset management and scene editing
- ✅ Everything you need to create games
- ✅ No build tools or GitHub required
👉 Download Untold Engine Studio
Just download the DMG, install, and start creating your game!
Want to contribute to the engine core? This repository contains the engine's fundamental systems:
- Rendering (Metal-based)
- Physics and collision detection
- Entity-Component-System (ECS)
- Animation and scene graph
- Input handling
Clone this repository if you want to improve or extend the engine itself.
See the open issues for a list of proposed features (and known issues).
- Top Feature Requests (Add your votes using the 👍 reaction)
- Top Bugs (Add your votes using the 👍 reaction)
- Newest Bugs
Reach out to the maintainer at one of the following places:
If you want to say thank you or/and support active development of Untold Engine:
- Add a GitHub Star to the project.
- Tweet about the Untold Engine.
- Write interesting articles about the project on Dev.to, Medium or your personal blog.
Together, we can make Untold Engine better!
We welcome contributions to the Untold Engine! Here’s how you can help:
- Fix Bugs: Review open issues labeled help wanted.
- Improve Features: Enhance existing systems, such as adding collision detection to the physics system.
- Create Tutorials: Write how-to guides or share examples to help other developers.
- Expand the Engine: Suggest and implement new features like AI systems or advanced shaders.
See the Contribution Guidelines for details.
A huge thanks to the people helping shape the Untold Engine. Your support and contributions make the project better every day.
This project is licensed under the LGPL v3.0.
- Developing a Game: You can use the Untold Engine to build your game without needing to open source your game’s code.
- Modifying the Engine: If you make changes to the engine itself, those changes must be open-sourced under the LGPL v3.0.
- Stronger Protections: LGPL v3.0 adds explicit patent protection and compatibility with modern licenses like Apache-2.0 (used by OpenUSD).
| You want to… | Allowed? | Obligations |
|---|---|---|
| Build a game with Untold Engine | ✅ Yes | No need to open source your game’s code |
| Modify Untold Engine internals | ✅ Yes | Must share modifications under LGPL v3.0 |
| Distribute the Untold Engine | ✅ Yes | Keep the LGPL license intact |
| Use for commercial projects | ✅ Yes | No royalties or fees |
| Combine with Apache-2.0 libs (e.g. OpenUSD) | ✅ Yes | Fully compatible under LGPL v3.0 |
For more details, see the full license text here.
💡 Our philosophy: You’re free to build with Untold Engine however you like — but if you improve the engine itself, those improvements should be shared back so the whole community benefits.
To keep communication clear and accessible for everyone:
- 💡 Use GitHub Discussions for feature proposals, ideas, or general questions.
- 🐞 Use GitHub Issues for bugs or concrete tasks that need tracking.
This way, conversations stay organized, visible to the community, and future contributors can benefit from past discussions.