Box3D
The most recommended of 7 physics engines
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.
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.
14 people gave an opinion
- recommend it
- 14
- criticize it
- 0
- approval share
- 100%
Recommended in 1 of 13 months
- November 2025: not recommended
- December 2025: not recommended
- January 2026: not recommended
- February 2026: not recommended
- March 2026: not recommended
- April 2026: not recommended
- May 2026: not recommended
- June 2026: not recommended
- July 2026: recommended
- August 2026: not recommended
- September 2026: not recommended
- October 2026: not recommended
- November 2026: not recommended (month in progress)
Why it doesn’t carry the badge
- 14 people recommend itNeeds 10 or more, met.
- Nobody criticizes itNeeds 2 to 1 or better, met.
- Recommended in 1 of 13 monthsNeeds 4 or more, not met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Released publicly as open source
“Nice to see it really is open-source now.”
Comment from 1 Jul 2026 in “Announcing Box3D :: Box2D” “glad to see it released out to the public”
Comment from 1 Jul 2026 in “Announcing Box3D :: Box2D” “Great to finally see Box3D released!”
Comment from 2 Jul 2026 in “Announcing Box3D :: Box2D” Trusted author with Box2D history
“Oh I'm so ready for this.. I've had some success with Box2D in the past”
Comment from 1 Jul 2026 in “Announcing Box3D :: Box2D” “This is a great library and Erin deserves your support.”
Comment from 1 Jul 2026 in “Announcing Box3D :: Box2D” “many thanks for amazing work you did”
Comment from 2 Jul 2026 in “Announcing Box3D :: Box2D” Deterministic across platforms
“the original Box3D library in floats is guaranteed deterministic across ARM and x64 already”
Comment from 12 Jul 2026 in “Fixed3D, a fixed point conversion of Box3D (box2d.org)” “Box3D is designed to be deterministic across thread counts and platforms.”
Comment from 1 Jul 2026 in “Announcing Box3D :: Box2D” Clean C API with bindings
“I am excited for Box3D because it’s written in C so it will have ergonomic bindings”
Comment from 2 Jul 2026 in “Announcing Box3D :: Box2D” “The C APIs for Box2D and now Box3D are just so nice to work with.”
Comment from 1 Jul 2026 in “Announcing Box3D :: Box2D”
Other physics engines people recommend
The four most recommended other physics engines, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| Box3DThis page | 14 | 0 | 100% | 1 | — | — |
| Box2D | 12 | 1 | 92% | 1 | — | — |
| MuJoCo | 10 | 0 | 100% | 6 | — | Approved |
| Jolt Physics | 9 | 2 | 82% | 5 | — | — |
| Rapier physics engine | 6 | 0 | 100% | 4 | — | — |
What people said
15 of the 19 comments that mention it, newest first. Each links to the original comment.
“the original Box3D library in floats is guaranteed deterministic across ARM and x64 already”
“Earlier box3d post was literally catalyzed by Unreals physics engine lacking some 3 line of code”
“many thanks for amazing work you did”
“I am excited for Box3D because it’s written in C so it will have ergonomic bindings”
“Great to finally see Box3D released!”
“Box2D/3D would make physics synchronisation a lot easier.”
“Box3D is designed to be deterministic across thread counts and platforms.”
“Very easy to build, and quite small.”
“glad to see it released out to the public”
“This is a great library and Erin deserves your support.”
“Oh I'm so ready for this.. I've had some success with Box2D in the past”
“Yeah this library is great. Use it!!!”
“Nice to see it really is open-source now.”
“The C APIs for Box2D and now Box3D are just so nice to work with.”
“Any addition to this small and exclusive list is very welcome”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.