# BOSL2 library for OpenSCAD

22 Hacker News commenters recommended BOSL2 library for OpenSCAD and 3 criticized it, November 2025 to November 2026. It was recommended in 8 of 13 months. It meets the Hacker Approved badge rule.

**Verdict:** Extends OpenSCAD with chamfers, fillets, rounding and attachment operations, saving much manual work. Caveat: an extra set of functions to remember, and can be slow with many fillets.

## Why people recommend it

- Easy chamfers, fillets and rounding (5 comments): "alleviates most issues I've run into with OpenScad for chamfers and the like, but it is an extra set of functions you need to remember sadly" ([source](https://news.ycombinator.com/item?id=47589128)) "BOSL2 is a great library to use with Openscad. It provides a bunch of primitives shapes functions with chamfer/rounding parameters." ([source](https://news.ycombinator.com/item?id=46793239)) "adds proper filleting, rounding, and attachment operations that vanilla OpenSCAD lacks" ([source](https://news.ycombinator.com/item?id=46345037))
- Powerful; essential for OpenSCAD users (6 comments): "it turnes an already very powerful tool into something insane" ([source](https://news.ycombinator.com/item?id=46522487)) "BOSL2 is SO nice and powerful, can also highly recommend it!" ([source](https://news.ycombinator.com/item?id=46339999)) "I'd recommend people to use the BOSL2 library for OpenSCAD" ([source](https://news.ycombinator.com/item?id=50035552))
- Attachment points and anchoring (3 comments): "BOSL2 allows attaching when you define attachment points or something with attachment points defined for you" ([source](https://news.ycombinator.com/item?id=46339193)) "Anchoring is a huge improvement, which does eliminate a lot of that work." ([source](https://news.ycombinator.com/item?id=46033938)) "the attachments with BOSL2 are really great" ([source](https://news.ycombinator.com/item?id=46799519))
- Covers extra features you'd otherwise build (2 comments): "I also have to recommend the BOSL2 library which means you don't have to implement all of those one million features" ([source](https://news.ycombinator.com/item?id=46338394)) "most of my additional feature needs are covered by the BOSL2 library" ([source](https://news.ycombinator.com/item?id=45978349))

## What people warn about

- Extra functions to remember (1 comments): "alleviates most issues I've run into with OpenScad for chamfers and the like, but it is an extra set of functions you need to remember sadly" ([source](https://news.ycombinator.com/item?id=47589128))
- Slow with many fillets (2 comments): "It's also extremely slow: it implements chamfers and fillets using morpho, and if you have a large number of fillets, the morpho algorithms" ([source](https://news.ycombinator.com/item?id=47590921)) "It's also extremely slow: it implements chamfers and fillets using morpho, and if you have a large number of fillets" ([source](https://news.ycombinator.com/item?id=47590453))

## Alternatives hackers recommend

- [build123d](https://hackerapproved.com/p/build123d.md): 53 recommend
- [CadQuery](https://hackerapproved.com/p/cadquery.md): 40 recommend
- [Cadova](https://hackerapproved.com/p/cadova.md): 5 recommend

## Cite as

Hacker Approved, "BOSL2 library for OpenSCAD", https://hackerapproved.com/p/bosl2-library-for-openscad/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).