# Box3D

> **TL;DR.** Box3D is an open-source 3D physics engine for games, written in portable C17 with an MIT license.

- **Category:** Gaming / Game Engines / Physics
- **Stage:** nascent
- **Age:** 3 days
- **Origin date:** 2026-06-30
- **First detected:** 2026-07-02
- **Canonical URL:** https://earlyterms.com/term/box3d
- **Sources:** 5 primary URLs

## Definition

Box3D is an open-source 3D physics engine for games, written in portable C17 with an MIT license. It brings the architecture of the widely-used [Box2D](https://box2d.org/) engine into three dimensions, adding mesh collision, height-field terrain, and joints for rigid-body simulation.

Erin Catto, Box2D's original creator, announced Box3D on [June 30, 2026](https://box2d.org/posts/2026/06/announcing-box3d/), built out of frustration with Unreal Engine's Chaos physics — which lacked gyroscopic torque and had broken continuous collision — while developing his own game, The Legend of California, at Kintsugiyama Interactive; the Hacker News launch thread hit 506 points within two days.

## Example

Kintsugiyama's in-development game The Legend of California uses Box3D to simulate falling redwoods, ragdolls, and voxel terrain at scale — the workload that motivated Catto to abandon Unreal's native Chaos system in the first place.

## Analogy

Think of it as Box2D given a third dimension and a C engine under the hood, built by the same person who wrote the original.

## Why it's emerging now

Erin Catto — creator of the ubiquitous Box2D engine — open-sourced Box3D on June 30, 2026 after hitting real limits in Unreal Engine's Chaos physics while building his own game. The Hacker News launch thread hit 506 points in under two days.

## Related terms

- *parent:* Box2D
- *competitor:* Jolt Physics
- *competitor:* Bullet Physics
- *competitor:* PhysX
- *competitor:* Rapier
- *competitor:* Chaos Physics
- *related:* Unreal Engine 6
- *related:* Rubikon
- *related:* Erin Catto
- *related:* The Legend of California

## Sources

1. [Erin Catto — Announcing Box3D (Box2D blog)](https://box2d.org/posts/2026/06/announcing-box3d/)
2. [erincatto/box3d — GitHub repository](https://github.com/erincatto/box3d)
3. [Box3D, an open source 3D physics engine — Hacker News](https://news.ycombinator.com/item?id=48745445)
4. [Kintsugiyama — Box3D is now open source](https://www.kintsugiyama.com/updates/box3d-is-now-open-source)
5. [ByteIota — Box3D: The Open-Source 3D Physics Engine Built for Games](https://byteiota.com/box3d-the-open-source-3d-physics-engine-built-for-games/)

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_Generated by EarlyTerms · https://earlyterms.com/term/box3d_