Side-by-side comparison of the game Fortnite before and after the "Lumen" upgrade.
Unreal Engine in Fortnite before and after the Lumen upgrade Epic Games
Game engines are the heart of video game creation, streamlining and simplifying development by handling graphics, physics, audio, artificial intelligence, and user input. Popular engines, such as Unity, Unreal, and Godot, offer pre-built frameworks and tools, allowing developers to focus on unique content and gameplay.

Have you ever played video games and wondered how they’re made or how they even work? The secret is in the game engine, the complex set of software tools that lies at the heart of every modern video game today.

What Is a Game Engine and How Does It Work?

Imagine you’re an artist, preparing to create your masterpiece. You’ll need tools of some sort to do the job. These could include brushes, paints, and a canvas to bring your vision to life.

Similarly, game developers need a game engine to design, develop, and breathe life into their virtual worlds. A game engine is a software framework that streamlines, accelerates, and simplifies the game development process.

Essentially, a game engine takes care of the heavy lifting of game creation. At least when it comes to the technical aspects of the work. It handles graphics, physics, sound, artificial intelligence, user input, and more.

In the early days of game development, a game would be written in machine code or something close to it (such as Assembly language) after being designed on paper. However, as games became more complex, game developers realized they’d have to create game development tools before creating their actual games. These tools and core game components became what we know as game engines today.

RELATED: Which Game Engine Should You Choose?

Components of a Game Engine

A game engine isn’t a single monolithic thing. They consist of several components that work together to create the final gaming experience. While this isn’t an exhaustive list, some key components include:

  • Graphics Engine: This renders the game’s visuals, such as 2D or 3D graphics, textures, and animations. Everything you see in the game is a result of the rendering engine.
  • Physics Engine: This simulates the game’s physical world. It manages collisions, gravity, and other real-world physics. Or unrealistic physics, but either way, you need something doing the physics math in-game.
  • Audio Engine: This part handles the game’s sound design, including music, sound effects, and voiceovers. Games like Returnal have complex 3D audio engines that take immersion to the next level.
  • Artificial Intelligence: The AI system controls non-player characters (NPCs) and other game world elements. It animates these characters by dictating their behavior, decision-making, and interactions with the player. This is perhaps the most exciting area for game development in coming years as AI technology explodes in complexity.
  • Input Management: This component oversees user input, such as keyboard, mouse, and controller actions. It translates these inputs into in-game actions. This might sound boring, but input management is crucial. Any game that controls poorly is no fun to play no matter how good it looks and sounds.

Each game engine has different approaches to these different areas under the hood. Engine developers strive to get the best results in each area as efficiently as possible.

The Role of a Game Engine in Game Development

Game engines play a vital role in streamlining the game development process. They allow developers to concentrate on generating unique content and gameplay mechanics instead of building all the underlying technology from scratch. By providing a pre-built framework, game engines save time and resources, allowing developers to iterate and refine their games more efficiently.

Moreover, game engines often come with built-in tools and editors for level design, animation, scripting, and more. These tools make it easier for developers to visualize their ideas and bring their game worlds to life.

Game studios with in-house engines benefit by using the same engine across multiple titles. For example, the game Horizon: Forbidden West uses the same Decima engine as its precursor Horizon: Zero Dawn. However, because the studio is now well-versed in the engine, the second game is much larger and more complex than the first.

Some companies develop game engines specifically to license them out to other studios. Developing and maintaining a game engine is incredibly difficult and expensive, so only the largest studios these days bother. For small to medium developers, it’s easier to license an existing engine and spend their resources on making their game with those tools.

Popular Game Engines

Various game engines are available, each with its own strengths and weaknesses. Some well-known game engines include:

  • Unity: Unity is a versatile, widely-used game engine that supports both 2D and 3D game development. Its user-friendly interface and extensive asset store make it popular among indie developers. While Unity has developed a reputation for resulting in poorly optimized games, plenty of studios have shown that in the right hands this engine can produce astonishing resuts.
  • Unreal Engine: Created by Epic Games, Unreal Engine is renowned for its cutting-edge graphics and robust toolset. It’s frequently used in AAA games and has gained popularity among developers seeking top-notch visuals and performance. The latest version, Unreal Engine 5, is set to further extend this engine’s dominance as many large studios are dropping their in-house engines in favor of Unreal.
  • Godot: Godot is an open-source game engine that has gained attention for its ease of use, flexibility, and multi-platform support.

These are just a small sample of the engines out there, other notable mentions include ID Tech, Cryengine, and redENGINE. But honestly, the list is enormous.

Iconic Games and Their Engines

Numerous iconic games have been built using these popular game engines. Let’s take a look at some notable examples:

  • Unity: Hollow Knight, an indie action-adventure game featuring beautiful hand-drawn art and engaging gameplay, is one of the most famous Unity-powered games. Other noteworthy Unity games include Ori and the Blind Forest and Cuphead.
  • Unreal Engine: Epic Games’ own Fortnite showcases the capabilities of the Unreal Engine in delivering large-scale, multiplayer experiences. Other iconic games that utilized Unreal Engine include BioShock Infinite and Gears of War.
  • Godot: Although relatively new, Godot has already been employed in developing impressive games such as The Garden Path, a beautiful and whimsical free-form gardening game.
  • CryEngine: The Crysis series, celebrated for its groundbreaking graphics and demanding system requirements, exemplifies CryEngine’s potential. The engine’s prowess in creating visually stunning games is also evident in Ryse: Son of Rome.
  • RPG Maker: To the Moon, an indie RPG with a heartfelt story and unique gameplay, shines as an example of what can be achieved using RPG Maker. The engine’s ease of use and dedicated community have given rise to many other memorable titles.
  • ID Tech: Developed by id Software, the ID Tech engine has been instrumental in shaping the first-person shooter genre. Pioneering games like Doom and Quake are just a few examples of iconic titles that were powered by this game engine. Its advanced technology and focus on performance have made it a favorite among FPS developers for decades.

The look and feel of many games are often the result of the engine they’re made with. There’s a familiar character to the various Elder Scrolls games, for example, that translates to Fallout 3, 4 and New Vegas, since they share a game engine. Likewise, it’s often easy to pick out which games have been developed using Unreal Engine, because of its distinctive quirks.

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Sydney Butler has over 20 years of experience as a freelance PC technician and system builder. He's worked for more than a decade in user education and spends his time explaining technology to professional, educational, and mainstream audiences. His interests include VR, PC, Mac, gaming, 3D printing, consumer electronics, the web, and privacy. He holds a Master of Arts degree in Research Psychology with a focus on Cyberpsychology in particular.
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