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#781 in Math

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378 downloads per month
Used in 11 crates (9 directly)

0BSD license



Blog | Community | Contribution Guide


Fornjot is an early-stage CAD kernel, using boundary representation (b-rep), written in the Rust programming language.

As a CAD kernel, the project's main goal is to provide a solid foundation for developers to build on top of, whether for special purpose tooling, third-party libraries for extending Fornjot's feature set, or full-featured CAD applications.

In doing so, Fornjot follows these principles:

  • Focus on mechanical CAD applications, like 3D printing, machining, woodworking; over other use cases such as architecture or electronics.
  • Favor reliability over features. Anything you can do should either work as expected, or result in a clear and actionable error.
  • Maintain a friendly API for directly defining models in Rust. This means code-first CAD modeling (or Code-CAD) is natively supported.
  • Support code-first CAD modeling in other languages, by enabling third-party APIs.

Fornjot is still in development and doesn't always live up to these ambitions. None the less, these are the priorities the project follows.

For more information, please check out the website.


Fornjot is supported by @MitchellHansen, @webtrax-oz, @seanjensengrey, @reivilibre, @lthiery, @ahdinosaur, @martindederer, @bollian, @sucaba, @nullstyle, @tachiniererin, @HalfVoxel, @MattOslin, @jminer, @voxpelli, @U007D, @guillaumechauvat, @mayfieldiv, @bglw, @hansihe, @romixlab, @krl, and my other awesome sponsors. Thank you!

Please consider supporting me too, to help make Fornjot sustainable long-term.

Table of Contents


Fornjot is usable for simple models (see examples), but currently lacks the features for anything more advanced. Work to change that is underway.


Fornjot features a modular architecture, allowing you to pick and choose which parts of it you want to use. It is made up of the following libraries:

  • fj: All-in-one API that re-exports all of the following crates.
  • fj-math: Math primitives used by the rest of Fornjot.
  • fj-interop: Basic types that allow other crates to interoperate, without depending on each other.
  • fj-core: Core primitives and code operating on those primitives.
  • fj-export: Exports Fornjot models to external data formats.
  • fj-viewer: Displays Fornjot models.
  • fj-window: Simple windowing abstraction for use with fj-viewer.


Fornjot is a set of Rust libraries (see list above). The definitive documentation on how to use those is their reference documentation. The crates.io pages of each library (see list above) link to those.

If you want to use Fornjot to create a specific model in Rust, the best starting point are the example models in this repository:

  • To display a model, run cargo run -p cuboid (replace cuboid with name of model you want to display).
  • To export a model, run cargo run -p cuboid -- --export model.3mf (replace cuboid with name of model you want to export; optionally replace 3mf with another supported file format).
  • To see full set of CLI options, run cargo run -p cuboid -- --help (all models have the same CLI interface, so this shouldn't differ much between them).


If you are interested in Fornjot, please consider joining the community. We'd love to have you!

Please check out the community page on the website for information on where to find us!

Get Involved

If you are interested in helping out, just fork one of the GitHub repositories and submit a pull request:

If you don't know what to work on, check out the good first issues. If you need some more guidance, check out the contribution guide, or just ask!


This project is open source, licensed under the terms of the Zero Clause BSD License (0BSD, for short). This basically means you can do anything with it, without any restrictions, but you can't hold the authors liable for problems.

See LICENSE.md for full details.


~155K SLoC