--- title: Box3D: The Legendary Box2D Physics Engine Goes 3D! description: Box3D is a new open-source 3D physics engine created by Erin Catto, the original author of Box2D. It was born out of frustration with Unreal Engine's Chaos... canonical: https://daily.dev/posts/box3d-the-legendary-box2d-physics-engine-goes-3d--lc92pr1en twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Box3D: The Legendary Box2D Physics Engine Goes 3D! | daily.dev og:description: Box3D is a new open-source 3D physics engine created by Erin Catto, the original author of Box2D. It was born out of frustration with Unreal Engine's Chaos... og:url: https://daily.dev/posts/box3d-the-legendary-box2d-physics-engine-goes-3d--lc92pr1en og:image: https://api.daily.dev/og/posts/LC92pR1en.png og:image:alt: Box3D: The Legendary Box2D Physics Engine Goes 3D! og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Box3D: The Legendary Box2D Physics Engine Goes 3D! **[Gamefromscratch](https://daily.dev/sources/gamefromscratch)** · 13 min read · 0 upvotes · 0 comments ## Summary Box3D is a new open-source 3D physics engine created by Erin Catto, the original author of Box2D. It was born out of frustration with Unreal Engine's Chaos physics while developing a survival game called The Legend of California. Box3D is built on Rubicon, Valve's internal CPU-based physics engine used in Half-Life: Alyx, combined with algorithms from Box2D and new code. Written in portable C17, it features continuous collision detection, convex hulls, capsule/sphere/triangle mesh shapes, multi-threading, SIMD optimization, cross-platform determinism, and various joint types. It runs on Windows, Mac, and Linux, requires no external dependencies, and is available under the MIT license. The post also surveys other 3D physics options including Jolt (now default in Godot 4.5), Bullet, Havoc, PhysX, and Rapier. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is Box3D and who created it? Box3D is a new open-source 3D physics engine created by Erin Catto, the original creator of Box2D. It extends Box2D's algorithms into three dimensions and is built partly on Rubicon Light, a hobby fork of Valve's Rubicon physics engine used in Half-Life: Alyx. It's released under the MIT license, written in portable C17, and runs on Windows, macOS, and Linux. _Developers evaluating new physics engines for their game stack can follow releases like Box3D on daily.dev._ ### Why did the creator of Box3D build a new physics engine instead of using Jolt or Unreal's Chaos physics? Unreal Engine's Chaos physics lacked support for simulating gyroscopic torque, causing slender shapes to spin incorrectly, and had continuous collision issues that made falling trees teleport erratically in a survival game called Legend of California. The developer, a physics programmer, considered forking Jolt but instead built on Rubicon, Valve's internal physics engine from Half-Life: Alyx, ultimately evolving that fork into Box3D. _Teams weighing Chaos, Jolt, or a custom physics engine can track these trade-offs on daily.dev._ ### What physics engine does Godot use by default as of version 4.5? As of Godot 4.5, Jolt is the default built-in physics engine, replacing Godot's previous custom solution that was reportedly based on Bullet. Jolt, an open-source MIT-licensed physics engine, is also used commercially in games like Horizon Forbidden West and Death Stranding 2. _Godot developers tracking default engine changes like this one can follow updates on daily.dev._ ## Similar posts on daily.dev - [Box3D Debuts As New Open-Source 3D Physics Engine](https://daily.dev/posts/box3d-debuts-as-new-open-source-3d-physics-engine-xsk1j9ymw) · Phoronix · 0 upvotes · 0 comments - [Announcing Box3D :: Box2D](https://daily.dev/posts/announcing-box3d-box2d-mu8ehdvki) · Lobsters · 0 upvotes · 0 comments - [Lightweight Box3D Physics Plug-In For Unreal Engine 5](https://daily.dev/posts/lightweight-box3d-physics-plug-in-for-unreal-engine-5-xpojprmph) · 80 LEVEL · 0 upvotes · 0 comments --- Tags: [#open-source](https://daily.dev/tags/open-source), [#game-development](https://daily.dev/tags/game-development) [View this post on daily.dev](https://daily.dev/posts/box3d-the-legendary-box2d-physics-engine-goes-3d--lc92pr1en) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Box3D: The Legendary Box2D Physics Engine Goes 3D!","url":"https://daily.dev/posts/box3d-the-legendary-box2d-physics-engine-goes-3d--lc92pr1en","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/box3d-the-legendary-box2d-physics-engine-goes-3d--lc92pr1en"},"datePublished":"2026-07-06T15:14:19.552Z","dateModified":"2026-09-14T07:00:59.996Z","description":"Box3D is a new open-source 3D physics engine created by Erin Catto, the original author of Box2D. 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