# Star Engine (CIG)

The Star Engine is a proprietary game engine developed by Cloud Imperium Games (CIG) for Star Citizen, knows as an ambitious space simulation game. It originated as a heavily modified version of Amazon's Lumberyard engine, which itself was based on CryEngine 3 (developed by Crytek). Over time, CIG made extensive modifications to accommodate Star Citizen's large-scale universe, real-time object streaming, and seamless space-to-ground transitions.
Star Engine is used in the development of Star Citizen, a highly anticipated game. It is designed to support large-scale maps and detailed rendering.

## Introduction

Star Engine is a proprietary game engine developed by Cloud Imperium Games (CIG) to power Star Citizen, an ambitious space simulation game known for its large-scale universe and high-fidelity graphics. Originally based on CryEngine 3, the engine has undergone extensive modifications over the years, incorporating advanced rendering techniques, real-time object streaming, and large-scale multiplayer networking.
The transition from CryEngine 3 to Amazon Lumberyard represents a significant shift in the game development landscape, driven primarily by Amazon's strategic integration of its cloud services. Lumberyard, while built upon the foundation of CryEngine 3, was designed to leverage Amazon Web Services (AWS) to facilitate the creation of online multiplayer games and cloud-connected experiences.
A core driver for this transition was Amazon's intent to provide developers with a comprehensive ecosystem that seamlessly combines game engine technology with cloud infrastructure. This integration allows for features such as scalable multiplayer servers, cloud-based storage, and analytics, which were previously more complex to implement with CryEngine 3.
StarEngine’s core strengths lie in its ability to handle seamless planetary transitions, large-scale multiplayer interactions, and complex physics simulations. Its real-time object streaming system ensures efficient memory management by dynamically loading assets based on player proximity, reducing performance overhead in an expansive, persistent universe. The engine also supports procedural generation, allowing for the creation of detailed planetary surfaces and diverse environments without requiring manual asset placement.
Star Engine is a heavily refactored version of CryEngine 3, initially used by Cloud Imperium Games (CIG) for Star Citizen since the first in-engine video released during its crowdfunding campaign. The last known CryEngine update integrated into Star Citizen’s codebase was Patch 3.8. Internally, the engine had been referred to as 'Star Engine' since at least September 2016, prior to the official transition to Amazon Lumberyard.

## History
### Transition

The foundation of Star Engine can be traced back to CryEngine 3, the game engine developed by Crytek, which was initially chosen by CIG in 2011 for Star Citizen’s development. CryEngine was known for its cutting-edge graphics and advanced physics, making it an ideal choice for a game aiming to deliver high-fidelity visuals and realistic space simulation. At the time, CryEngine had powered visually groundbreaking titles such as Crysis and Ryse: Son of Rome, reinforcing its reputation as a top-tier rendering engine. However, as development progressed, it became clear that CryEngine was not designed to support the massive multiplayer experience and procedural universe generation that Star Citizen required. The engine was built primarily for single-player and small-scale multiplayer experiences, which posed significant technical challenges when adapting it to handle seamless space travel, dynamic environments, and an interconnected universe with thousands of concurrent players.

### Development of the engine

To overcome the limitations of CryEngine, Cloud Imperium Games (CIG) announced in 2016 that they had transitioned to Amazon Lumberyard, a new engine derived from CryEngine but further developed by Amazon to support cloud-based networking and large-scale multiplayer infrastructure. This decision was not merely a technical upgrade but a strategic move that aligned with the long-term vision of Star Citizen. At the time, Crytek was facing severe financial difficulties, raising concerns about the future stability and support of CryEngine. CIG needed an engine with a more secure and well-supported development pipeline, ensuring they would not be reliant on a struggling third-party company.

### Lumberyard

Amazon Lumberyard, being integrated with Amazon Web Services (AWS), offered a more scalable solution for Star Citizen’s ambitious multiplayer and persistent world design. The integration of AWS allowed CIG to take advantage of cloud-based computing, offloading significant processing tasks to distributed servers and ensuring smoother performance for an expansive universe where thousands of players could interact in real-time. This cloud infrastructure was crucial for implementing features like persistent player interactions, real-time economic systems, and large-scale battles without the constraints of traditional server architectures.
Furthermore, Lumberyard’s licensing terms granted CIG far more freedom to customize the engine than what had been possible with CryEngine. Crytek’s original licensing agreement-imposed restrictions that limited the degree of modification and expansion that CIG could implement. By switching to Lumberyard, CIG gained the ability to overhaul core engine components, develop proprietary technologies, and fully integrate their vision without external dependencies. This transition laid the groundwork for what would later become StarEngine, as CIG progressively reworked and enhanced Lumberyard to suit their needs, turning it into a highly specialized and optimized engine designed exclusively for Star Citizen and Squadron 42.

### Modifications

Following the transition to Lumberyard, Cloud Imperium Games (CIG) undertook extensive modifications, gradually transforming the engine into a custom-built platform designed specifically to support Star Citizen’s vast, interconnected universe. By 2017, the level of internal development and reengineering had become so extensive that the company officially rebranded it as Star Engine. Unlike a typical game engine that is designed for broad usage across multiple genres, Star Engine was purpose-built to meet the complex demands of a fully simulated, persistent spacefaring universe.
One of the most significant innovations of Star Engine was its ability to support seamless planetary transitions—allowing players to travel from deep space to a planet’s surface in real-time without any loading screens. This breakthrough was not just a visual enhancement but a fundamental shift in game world architecture, enabling an unprecedented level of immersion. To handle the vast amount of data required for this level of detail, real-time object streaming was implemented, dynamically loading and unloading assets based on player movement to optimize performance without sacrificing graphical fidelity.
Beyond rendering and world-building, Star Engine also introduced a groundbreaking server meshing technology. Traditional multiplayer games rely on singular, static game servers, often limiting player counts and world sizes. In contrast, Star Engine’s approach allowed multiple servers to work in unison, dynamically distributing processing loads and seamlessly transferring players between different server nodes. This architecture laid the foundation for a fully persistent universe, where players could interact in a constantly evolving world without artificial instancing or isolated game sessions.
Another major advancement came in the form of procedural planet generation, which enabled the creation of expansive and diverse planetary landscapes. Unlike hand-crafted environments that require extensive development time for each new location, this technology allowed StarEngine to generate planets and moons dynamically while still maintaining a high level of artistic control and realism. Complementing this, the Subsumption AI system was developed to govern NPC behavior, mission structures, and the in-game economy, allowing for emergent gameplay where AI characters respond intelligently to the world and player actions.

## Technical features

StarEngine features several advanced technologies that enable the vast and immersive world of Star Citizen. It utilizes a 64-bit world space coordinate system to support large-scale environments. Object Container Streaming and the Mega Map feature help optimize loading times and performance. The Zone System and Local Physics Grids allow seamless transitions between different areas of the game, while the Room System manages interior spaces dynamically.
Procedurally generated planets provide diverse landscapes, enhanced by Physically Based Rendering (PBR) for realistic lighting and materials. The Sun exists as a physical object, allowing for dynamic celestial interactions such as binary star systems and realistic light casting from explosions. Subsumption AI governs NPC behavior, while unified first- and third-person animations create a seamless player experience.
StarEngine supports a Unique Global Entity ID system and a Generic Instance Manager to track objects and interactions persistently. The Universe Simulator manages large-scale systems, while persistence features ensure player data, server presence, and game states remain intact. The Item Port System allows dynamic equipment management.
Networking is powered by Star Network, with GOST (Game Object State) undergoing a rework for improved efficiency. "Grabby Hands," now integrated into the Cargo and Loot systems, enhances player interaction with objects. Multi-LayerBlend character shader technology improves visual fidelity, while the iPredictor system enhances movement prediction. The backend architecture, Diffusion, provides a cloud-oriented service infrastructure to support the game’s complex systems.

## Receptions and criticisms

The development of Star Engine has been complicated by legal disputes. In December 2017, Crytek filed a lawsuit against CIG, alleging breach of contract and copyright infringement related to the use of CryEngine in Star Citizen and Squadron 42. This legal action underscored the complexities of developing a proprietary engine based on existing technologies.
There is uncertainty regarding whether Star Engine will be available for licensing, similar to Unreal Engine. While Epic Games actively licenses Unreal Engine to developers across various industries, Cloud Imperium Games (CIG) has not made any official statements about offering Star Engine as a licensable product. Given that Star Engine is heavily customized to meet the specific needs of Star Citizen and Squadron 42, some speculate that it may remain exclusive to CIG’s projects rather than being released as a general-purpose engine for third-party developers.
There is uncertainty about how Cloud Imperium Games (CIG) will handle future iterations of Star Engine. Since the engine is continuously evolving to meet the specific demands of Star Citizen and Squadron 42, it is unclear whether CIG plans to overhaul the engine with major updates, transition to a new underlying technology, or maintain an incremental development approach. Some speculate that as technology advances, CIG might need to make significant architectural changes to keep up with industry standards, while others believe that the studio will continue refining and optimizing the existing framework rather than adopting an entirely new engine.
Some industry observers have questioned the suitability of CryEngine, the foundation for Star Engine, for a large-scale space simulation like Star Citizen. Originally designed for small-scale first-person shooters, Cry Engine's adaptation to a massive multiplayer environment has been challenging. This choice has been criticized as a factor contributing to the project's prolonged development and technical hurdles.