Glossary

RealityKit

RealityKit is Apple's high-level 3D rendering and simulation framework, written in Swift. While ARKit senses the world, RealityKit draws and animates the virtual content on top: physically based materials, lighting, physics, audio and animation. With RealityKit 4 it spans iOS, iPadOS, macOS and visionOS, and on the Apple Vision Pro it is the primary way apps render 3D. It is a native-app technology, not something you touch to put AR on a website.

Quick Facts

Type: Apple 3D rendering and simulation framework (Swift)
Pairs with: ARKit (ARKit senses, RealityKit renders)
Platforms: iOS, iPadOS, macOS, visionOS (RealityKit 4)
Capabilities: PBR materials, physics, animation, MaterialX, ECS
Authoring: Reality Composer Pro
Web equivalent: not needed, use Web AR via PausAR Viewer

The clean split in Apple’s AR stack is sensing versus rendering. ARKit works out where the floor and walls are; RealityKit takes that and renders convincing 3D on top, with PBR materials, lighting, physics, particles, portals and character animation such as blend shapes, inverse kinematics and skeletal poses. RealityKit has used an Entity Component System (ECS) for structuring scenes from the start. With RealityKit 4, Apple unified the feature set across iPhone, iPad, Mac and Vision Pro, added MaterialX shaders, expanded character animation, and opened up low-level mesh and texture access for Metal. Scenes and materials are usually authored in Reality Composer Pro.

RealityKit is the path when you are building a native Swift app. To put 3D and AR on a WordPress site you do not need it at all. PausAR Viewer delivers Web AR through Apple Quick Look and Google Scene Viewer from one Elementor widget, so you skip Swift, Xcode and RealityKit entirely and still get true-to-scale AR on iOS and Android.

Comparison

Property	RealityKit	PausAR Viewer (WordPress)
Skill needed	Swift and Xcode	None, Elementor widget
Target	Native iOS and visionOS apps	Any website and browser
AR delivery	Build it yourself	Built in

FAQ

Do I need RealityKit to put AR on my website?

No. RealityKit is for native Swift apps. For a WordPress site, PausAR Viewer delivers Web AR via Apple Quick Look and Google Scene Viewer with no coding.

What is the difference between ARKit and RealityKit?

ARKit handles tracking and understanding the real world; RealityKit handles rendering and simulating the virtual content. Native apps use them together.

How does RealityKit relate to USDZ?

RealityKit renders USD and USDZ scenes, which are usually authored in Reality Composer Pro.