Unreal Engine

Unreal Engine
Information
Type	Game engine
Industry	Video games, film and television, architecture, automotive, simulation
Developer	Epic Games
Written In	C++
Operating System	Windows, macOS, Linux
License	Proprietary, source-available; royalty model
Supported Devices	PC, consoles, mobile, VR Headsets, AR devices
Release Date	1998 (first release); Unreal Engine 5 on April 5, 2022
Website	unrealengine.com

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Unreal Engine is a real-time 3D creation tool and game engine developed by Epic Games. It was first released in 1998 alongside the first-person shooter Unreal, and it has since grown into one of the most widely used engines for games, film and television, virtual reality (VR), augmented reality (AR), architecture, automotive design, and simulation. The engine is written in C++ and is programmed through a combination of C++ source code and Blueprints, a node-based visual scripting system that lets creators build gameplay logic without writing code.

For XR developers, Unreal Engine is a common choice for high-fidelity VR and AR projects. It ships with a ready-made VR template, supports the cross-vendor OpenXR standard, and provides rendering paths tuned for the demanding performance budget of head-mounted displays.

Overview

Unreal Engine is offered as a source-available product. The full C++ source code is available to licensees through Epic's GitHub, which lets studios modify the engine itself. Commercial games are governed by a royalty model: as of the licensing terms in force in 2026, Epic charges a 5% royalty on lifetime gross revenue above 1 million US dollars per product, and that royalty is waived for titles released on the Epic Games Store.

The engine runs on Windows, macOS, and Linux for development, and it can deploy to a wide range of targets including desktop PCs, game consoles, mobile devices, and VR and AR hardware.

Blueprints and C++

Programming in Unreal Engine happens in two complementary ways. C++ gives full access to the engine's systems and is used for performance-critical code. Blueprints, introduced in Unreal Engine 4 as the successor to the older Kismet system, provide visual scripting through a graph of connected nodes. Blueprints are widely used in VR development because they let designers prototype interactions such as grabbing, teleporting, and triggering events quickly, and the bundled VR template is built almost entirely from Blueprint logic.

Virtual reality and augmented reality

VR template

Unreal Engine includes a VR template that serves as a starting point for new VR projects. It provides example logic for teleport locomotion, grabbing and attaching objects to the hands, common input actions, and a VR spectator view that mirrors the headset image to a flat screen. The template is built on the OpenXR framework, so its logic is meant to work across multiple headsets and platforms without platform-specific code.

Input handling in the template was originally based on Unreal's Action and Axis mapping system. Later 5.x releases moved toward the Enhanced Input system, and Epic now recommends creating Enhanced Input actions rather than the deprecated legacy action mappings.

OpenXR support

OpenXR is the royalty-free open standard from the Khronos Group that provides a common interface to VR and AR hardware. Unreal Engine added OpenXR support that matured in version 4.27 and became the default path in Unreal Engine 5, replacing the need for separate vendor plugins in many cases. OpenXR in Unreal exposes controller and hand poses for natural interaction, including a Grip pose that represents the position of a closed hand holding an object and an Aim pose that represents a ray used to point at targets.

Hardware vendors layer their own plugins on top of Unreal's OpenXR support to expose device-specific features. Examples include the Meta XR plugin for Meta Quest headsets, the Microsoft OpenXR plugin for HoloLens 2 hand tracking, the HTC Vive OpenXR plugin, and Varjo's integration, which is built directly on Unreal's built-in OpenXR layer so that the standard binary engine can be used without vendor-specific code.

Forward rendering and MSAA

The recommended rendering path for VR in Unreal Engine is the forward shading renderer rather than the default deferred renderer. Forward shading gives a faster baseline for the stereoscopic, high-resolution rendering that VR requires, and it can use multi-sample anti-aliasing (MSAA), which produces a sharper image than the temporal anti-aliasing (TAA) typically used with deferred rendering. Meta recommends the forward renderer for Meta Quest development and for PC VR over Meta Link, with 4x MSAA as the suggested setting for Quest devices.

The trade-off is that forward rendering supports far fewer dynamic lights and meshes per scene than deferred rendering, so VR projects rely on optimization techniques such as level of detail (LOD) meshes and mesh merging to keep the draw count manageable.

To cut the cost of drawing the scene twice, once per eye, Unreal provides Instanced Stereo Rendering on PC, which renders both eye views in a single pass. On mobile VR hardware such as Quest, the equivalent feature is Mobile Multi-View, which renders objects once to the left eye buffer and duplicates them to the right with the correct per-eye adjustments. Mobile Multi-View requires the Vulkan graphics API, which is the supported rendering API on Quest.

Unreal Engine 4 to Unreal Engine 5

The first game built on Unreal Engine 4 was released in April 2014. Unreal Engine 5 entered early access on May 26, 2021, and was officially released for all developers on April 5, 2022, during Epic's State of Unreal event. Epic has continued to update the engine on a roughly twice-yearly cadence; version 5.7 reached stable release on November 12, 2025.

Unreal Engine 5 introduced two headline rendering features:

Feature	What it does
Nanite	A virtualized micropolygon geometry system that streams and renders very high-detail meshes with little impact on frame time, reducing the need for manual LOD work.
Lumen	A fully dynamic global illumination and reflections system that updates lighting in real time without precomputed light maps.

Caveat: Nanite and Lumen in VR

Although Nanite and Lumen are the defining features of Unreal Engine 5, they were not ready for VR when the engine launched, and their VR support has remained limited and evolving. At early access and at the 5.0 launch the new VR template disabled Lumen because it was not supported for headsets, and Epic stated that it had no timeframe to share for bringing Lumen and Nanite to VR while it explored how to extend those features to more platforms.

The core obstacle is performance. Lumen was designed around target frame rates of roughly 60 frames per second outdoors and 30 indoors on then-current console hardware, which is well below the 90 frames per second that most PC VR headsets expect, and stereoscopic rendering at higher resolutions makes VR more expensive still. As of the current documentation, Nanite and Lumen for XR are described as experimental and not officially supported. They work only on PC with the deferred renderer and DirectX 12, are not supported on mobile XR hardware, and since version 5.1 they render in both eye views, so even high-end systems can struggle to hold the target frame rate. Epic advises caution before shipping a VR product that relies on them.

In practice this means most production VR projects on Unreal Engine 5 still use the forward renderer with MSAA and avoid Nanite and Lumen, while drawing on the many other UE5 improvements such as World Partition for large worlds, the modeling tools, MetaSounds, and the updated editor.

Epic's own VR work

Epic Games has produced its own VR titles and demos, partly to showcase the engine. At Oculus Connect 2 in September 2015 the company showed Bullet Train, a free VR shooter demo for the Oculus Touch controllers that demonstrated VR locomotion and gunplay. That demo grew into Robo Recall, a full arcade shooter announced at Oculus Connect 3 on October 6, 2016, and released free for the Oculus Rift on March 1, 2017, with development funded by Oculus. A standalone version, Robo Recall: Unplugged, launched for the Oculus Quest on May 21, 2019.

It was also at Oculus Connect 3 that Oculus announced it would cover the Unreal Engine royalty fees, normally 5% of gross revenue, for any Unreal Engine app sold in its store, up to the first 5 million US dollars in gross revenue per app, which could save a developer as much as 250,000 US dollars.

Notable VR titles built in Unreal Engine

Many commercial VR games are built on Unreal Engine. A few well-known examples:

Title	Developer	Engine	Notes
Robo Recall	Epic Games	Unreal Engine 4	Arcade shooter; Epic's flagship VR showcase; Quest version Robo Recall: Unplugged in 2019.
Pavlov VR	Vankrupt Games	Unreal Engine 4	Multiplayer VR first-person shooter that uses the forward renderer; released on Steam February 27, 2017, later on Quest.
Into the Radius	CM Games	Unreal Engine 4	Single-player survival shooter with physics-based weapon handling; later ported to Quest.

Enterprise and virtual production

Beyond games, Unreal Engine is used in virtual production for film and television, where large LED stages display real-time engine scenes behind actors, and in enterprise fields such as automotive design, architectural visualization, and training simulation. These uses overlap with AR and VR through interactive design reviews and immersive walkthroughs, but they fall outside the engine's core gaming role.

See also

• OpenXR
• Game engine
• Robo Recall
• Epic Games
• VR Headsets