# Box3D 14 Hacker News commenters recommended Box3D and 0 criticized it, November 2025 to November 2026. It was recommended in 1 of 13 months. **Verdict:** Free open-source 3D physics library from Erin Catto, recommended for determinism across platforms and a clean C API. No recurring complaints appear in the quotes. ## Why people recommend it - Released publicly as open source (3 comments): "Nice to see it really is open-source now." ([source](https://news.ycombinator.com/item?id=48748902)) "glad to see it released out to the public" ([source](https://news.ycombinator.com/item?id=48750473)) "Great to finally see Box3D released!" ([source](https://news.ycombinator.com/item?id=48756880)) - Trusted author with Box2D history (3 comments): "Oh I'm so ready for this.. I've had some success with Box2D in the past" ([source](https://news.ycombinator.com/item?id=48749380)) "This is a great library and Erin deserves your support." ([source](https://news.ycombinator.com/item?id=48750187)) "many thanks for amazing work you did" ([source](https://news.ycombinator.com/item?id=48758762)) - Deterministic across platforms (2 comments): "the original Box3D library in floats is guaranteed deterministic across ARM and x64 already" ([source](https://news.ycombinator.com/item?id=48881796)) "Box3D is designed to be deterministic across thread counts and platforms." ([source](https://news.ycombinator.com/item?id=48750852)) - Clean C API with bindings (2 comments): "I am excited for Box3D because it’s written in C so it will have ergonomic bindings" ([source](https://news.ycombinator.com/item?id=48758027)) "The C APIs for Box2D and now Box3D are just so nice to work with." ([source](https://news.ycombinator.com/item?id=48748540)) ## Alternatives hackers recommend - [Box2D](https://hackerapproved.com/p/box2d.md): 12 recommend - [MuJoCo](https://hackerapproved.com/p/mujoco.md): 10 recommend - [Jolt Physics](https://hackerapproved.com/p/jolt-physics.md): 9 recommend - [Rapier physics engine](https://hackerapproved.com/p/rapier.md): 6 recommend - [BepuPhysics 2](https://hackerapproved.com/p/bepu-physics.md): 6 recommend ## Cite as Hacker Approved, "Box3D", https://hackerapproved.com/p/box3d/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).