Epic-Games’ Unreal Graphics Rendering and Game Engine

Unreal Game Engine

Unreal Game Engine

Unreal Engines are series of graphics rendering and game development engines developed by Epic Games over the past 23 years. This game engine has brought tons of features and improvements in the gaming industry and other industries, pushing against the graphics rendering limits. They introduced Unreal Engine I, II, III, IV, and Unreal Engine 5 which is under development

Since 1998, Unreal Engine is a rival to other engines in the market and went head-to-head with its competitors. As a result, today we have super-realistic graphics in this generation’s platforms and Epic Games, with its Unreal Engine, is one of the few who built the foundation of modern games.

In the past, there have been fiery debates (ignGamespot) dating back to the 2000s about which game was better, Quake III Arena or Unreal Tournament. I see that the topic is still hot among old-school FPS players (DoomWorldReddit). Look at this original Unreal Intro.

Table of Contents

Unreal Engine I

Unreal Engine I is a rendering engine developed by Epic Games in 1998. This engine was written in C++ and developed games for Windows and Mac OS. This engine mainly developed first person shooter (FPS) games. Unreal engine is developed by an American programmer, Tim Sweeney. The engine is free to use and available publicly.

In 1993, Doom was released with 3D first-person-shooter model. This created a new 3D genre for FPS game. Tim Sweeney, though previously had created small projects, now wanted to create a competitor 3D game engine which would stand up to its rivals. In 1995, Tim Sweeney began to work on a new game engine with advanced 3D graphics. In 1998, the game engine was finally developed and named as “Unreal”. Epic Games with release of Unreal Engine I, also introduced a new scripting language, known as Unreal Scripting (UScript).

On May 22, 1998, Unreal shipped. Critical acclaim, considerable sales, and a loyal community that took advantage of the Unreal script, expanding the game via the internet, made Epic an instant name in the game development community.


It was a basic 3D game engine at its inception but through the passage of time, many improvements and updates have been brought to this engine. Unreal was a single player game but later, with the advancement of Internet, multiplayer was also introduced in this game engine. Unreal Tournament exhibited the true power of Unreal Engine in terms of Multiplayer. Graphics quality was also improved very much. Each game released on this engine brought new graphical features with it. Unreal engine is used by many other companies other than Epic Games for the development of video games.

Unreal URLs were similar to Web and FTP URLs and users could go into portals and travel among user-run servers.


  • 3D Graphics
  • High Resolution Texture
  • Texture Filtering
  • Lighting
  • Screen Space Reflections
  • Collision Detection
  • S3TC Compression Algorithm

Games Developed in Unreal I

Deus Ex
Unreal Tournament
X-COM – Enforcer

Unreal Engine II

Unreal Engine II is a 2nd generation game rendering engine of Unreal Engines, developed by Epic Games in 2002. The engine was written in C++ programming language. This engine developed games for Windows, Mac OS, Xbox, PlayStation and Wii U. This engine is developed by Tim Sweeney along with 6 other programmers. This first game to run on this engine was America’s Army. The engine is commercially available to public with royalty model.

The base of Unreal Engine II is Unreal Engine I. But the rendering model is all new in this engine. It has high polygon model environments with new polygon pipeline rendering. This method provides new high details to the engine, in the form of meshes and terrain. The engine also uses new hardware TnL (Transform and Lighting) and GeForce3. New shaders were introduced in this engine as pixel shader and vertex shader effects. There are several plugins available to this engine for better graphics. The Unreal Editor or UnrealEd was also updated as UnrealEd 2.0 with Unreal Engine II.

We’ve been focusing a lot on, and taking advantage of the new hardware TnL (Transform and Lighting) cards, and the NV20 [GeForce3], and all the new pixel shader and vertex shader effects that are possible.

An Interview with Epic Games’ Tim Sweeney

Unreal Engine II also came out with its another version Unreal Engine 2.5 or Unreal Engine 2X. This version of the engine was much more optimized. It added further rendering performance and physics into the engine. It was also used for porting games on Xbox console.


  • Improved Resolution Textures
  • Tessellation
  • DirectX 8.1b
  • High Shadow Quality
  • Physics
  • Max and Maya Exports
  • Skeletal Animations

Games Developed in Unreal Engine II

Echo of soul
Splinter Cell – Conviction
Killing Floor
Splinter Cell – Blacklist

Unreal Engine III

Unreal Engine III is 3rd Generation engine of the Unreal Engines. This engine is developed by Epic Games in 2004. It is developed using C++ language and works on Windows, Mac OS, PlayStation, Xbox, Nintendo Switch, Android and iOS platforms. Unreal Engine III also supported DirectX 9. The engine is a free source engine but for any kind of title on Unreal Engine III, the party has to pay Epic Games as royalty model.

“The basic architectural decisions visible to programmers of an object-oriented design, a data-driven scripting approach, and a fairly modular approach to subsystems still remain [from Unreal Engine 1], But the parts of the game that are really visible to gamers, the Tenderer, the physics system, the sound system, and the tools are all visibly new and dramatically more powerful.”

Tim Sweeney

On the development of Unreal Engine III, Epic Games had been working with Nvidia to improve the functionality and performance of the engine. This engine required a high-end system to run smoothly at the time of its release. This engine debut on consoles with Gears of War (also known as Gears) on console while RoboBlitz on PC. In 2010 – 2011, android and iOS support were also added to this engine. Infinity Blade was the first iOS game and Dungeon Defenders was the first game to run on Android using Unreal Engine III. Unreal Engine III was not only used for gaming purposes, but it was also used for many non-gaming projects. It was used in making real-time animations and simulations.

Unreal Engine III has a huge variation in terms of developing any genre of game. It is used in making real time strategy, first person shooter, third person shooter and other types of games. This engine was introduced with general purpose shaders system with Pixel Shader 3. This system led to shading of the characters, objects and environment in the game very easily.

In Unreal Engine III, Epic Games introduced a new physics engine, NovodeX, for bringing the laws of physics from real world in to the game engine. This helped the quality of the in-game effects to appear realistic.

In 2010, Epic games brought 3D vision to the Unreal Engine III in collaboration with Nvidia. This allowed Unreal Engine III to allow integrated 3D Vision technology in to the game [Source].

“Having the number one 3D engine on the planet embrace 3D Vision is fantastic news for UE3 licensees, UDK users and gamers. It’s now easier than ever to add state-of-the-art stereoscopic 3D effects to your Unreal Engine 3-based creations”

Tony Tamasi, vice president of content and technology at NVIDIA.

Unreal Engine was available publicly, leading a lot of people to use Unreal Engine III for their projects. But they could not publish their work because they did not have engine’s license. Therefore, in 2014, Epic released its Unreal Development Kit (UDK) and made UDK open to public use.


  • High Resolution Texture
  • Color Precision
  • Gamma Correction
  • Texture Filtering
  • DirectX 11 Tessellation and Displacement
  • High Reflections
  • HDR
  • Post Processing Effects
  • Enhanced Visual Effects
  • Realtime Global Illuminations
  • Advanced Physics
  • Per Pixel Lighting
  • Soft-Body Dynamics
  • Depth of Field

Games Developed on Unreal Engine III

Xcom 2
Batman Arkham Origins
Mortal Kombat 11

Unreal Engine IV

Unreal Engine IV is 4th generation engine of Unreal Engines. Unreal Engine IV is developed by Epic Games and released in 2014. This engine is written in C++ and works on the platform of Windows, Mac OS, PlayStation, Xbox, Nintendo Switch, Android and iOS. This engine aimed at next generation of hardware. Unreal Engine IV was first time used in the development of Daylight. It works by default on Vulkan API. This source code of the engine is made public with royalty model license.

“Unreal Engine 4 will be totally groundbreaking and the way games will be done in the future,”

Mark Rein

One of the most significant work of the Unreal Engine 4 is Real-Time Global Illumination. This works on the principle of real-life light’s behavior and how it bounces from an object’s surface to another. To depict photon (light particles), it is very difficult and source utilizing task. Therefore, this global illumination technique is mostly used in certain CGI scenes in films, which are very complex.

The engine also used Sparse Voxel Octree Global Illumination (SVOGI) technique for generating octree. This technique was developed by Andrew Scheidecker at Epic Games. Octrees are used for generating 3D space by dividing a single texture node into 8 sub-nodes.

This 4th generation engine works on real-time lightmaps for each frame. These lightmaps are stored in 3-dimensional texture instead of last generation, where it was stored in 2-dimensional texture. This 3-dimensional texture is called Vortex. To make vortex efficient, it is organized in tree structure.

Epic Games used improved physics engine, powered by Nvidia PhysX in its 4th generation. PhysX deals with all of the collision queries and physical objects in the environment. Its purpose is to make real-life aspects into the game. But there was drawback that only Nvidia GPUs can utilize this technology from Unreal Engines. Later Epic Games released Unreal Engine 4.23, with a new better physics engine Chaos Destruction. Unreal Engine’s Chaos and Niagara combined together brought tons of details to the game world physics system. This allowed any manufacturer’s GPU to be able to utilize physics system from Unreal Engine IV.

Nvidia also added its Ray Tracing technology in Unreal Engine 4. This technology works with Nvidia’s RTX series graphics cards which have RT cores. These cores are specifically used for tracing the direct and indirect light sources and present a real-life lighting environment. This technology provides extreme lighting accuracy and quality. These GPUs render lighting on hardware level.


  • Intensive Global Lighting
  • Nvidia PhysX
  • Nvidia Ray Tracing
  • High Foliage Density
  • High Visual Effects
  • Very High-Resolution Textures
  • Tessellation
  • DirectX 12

Games Developed in Unreal Engine IV

Days Gone
Darksiders 3
Star Wars – Jedi Fallen Order

Unreal Engine 5 (UE5)

Unreal Engine 5 is currently under development it’s early access is now available. It’s features include Nanite which is a virtualized micropolygon geometry system, Lumen which is a fully dynamic global illumination solution, create open worlds faster, animation toolset, control on audio DSP (MetaSounds) and makeover of the editor. Unreal Engine 5 is scheduled to launch in early 2022.

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M. Saqib: Saqib is Master-level Senior Software Engineer with over 14 years of experience in designing and developing large-scale software and web applications. He has more than eight years experience of leading software development teams. Saqib provides consultancy to develop software systems and web services for Fortune 500 companies. He has hands-on experience in C/C++ Java, JavaScript, PHP and .NET Technologies. Saqib owns and write contents on mycplus.com since 2004.
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