manifold-rust

Support the Project

manifold-rust is open-source and free to use, maintained in spare time as a labor of love. Friends James Smith and Dan Ruskin help out from time to time too.

If you find it useful, here are a few ways to help keep development going:

• Donations: Buy Me a Coffee — every coffee helps.
• Star the repo: Costs nothing and helps others find the project.
• Report issues: Open an issue for bugs or feature ideas.
• Contribute: PRs welcome — open an issue first to discuss larger changes.

Pure Rust port of Manifold — a geometry library for 3D boolean operations on triangle meshes.

Part of the rust-apps suite — a collection of Rust graphics and geometry libraries by Lars Brubaker.

Status: Port complete. All 18 phases of the C++ engine (v3.5.0) are implemented and every C++ test is ported or covered — 520 tests passing, 0 failing (the handful of #[ignore]d tests are debug-build-speed only and pass in release). Heavy boolean/CSG workloads run at parity with the sequential C++ build, and the optional parallel feature roughly doubles them. See PORTING_PLAN.md for the full record.

What is Manifold?

Manifold is a high-performance C++ library for 3D solid modeling. It supports:

• Boolean operations (union, intersection, difference) on triangle meshes
• Mesh constructors (sphere, cube, cylinder, extrude, revolve)
• Cross-section (2D polygon) operations
• Smooth subdivision and SDF-based mesh generation
• Convex hull
• Minkowski sum/difference

This Rust port targets exact numerical match with the C++ implementation — same algorithms, same floating-point results, same triangle topology. Exactness is validated by instrumented, boolean-by-boolean trace comparison against a locally built C++ reference (see validate-reference.ps1), down to the tie-breaking order of symbolic-perturbation predicates.

Why

MatterHackers uses 3D mesh boolean operations extensively in production for 3D printing workflows. A pure Rust implementation avoids FFI overhead and integrates cleanly with Rust tooling including WASM compilation.

Installation

Available on crates.io:

cargo add manifold-rust

API documentation: https://docs.rs/manifold-rust

Usage

use manifold_rust::manifold::Manifold;
use manifold_rust::linalg::Vec3;

// Constructors
let cube = Manifold::cube(Vec3::new(1.0, 1.0, 1.0), true);
let sphere = Manifold::sphere(0.6, 32);

// Guaranteed-manifold booleans (also available as + - operators)
let difference = cube.difference(&sphere);
assert_eq!(difference.status(), manifold_rust::types::Error::NoError);

// Measure
println!("volume = {}", difference.volume());
println!("area   = {}", difference.surface_area());
println!("genus  = {}", difference.genus());

// Mesh I/O via MeshGL
let mesh = difference.get_mesh_gl(0);
let round_tripped = Manifold::from_mesh_gl(&mesh);

Enable parallel execution (results stay bit-identical to the sequential build — only determinism-preserving sites are parallelized):

[dependencies]
manifold-rust = { version = "0.9", features = ["parallel"] }

Demo

An interactive WASM demo is live at https://larsbrubaker.github.io/manifold-rust/ — booleans, extrude/revolve with twist, convex hull, subdivision, a Menger sponge, and more, all running the Rust engine compiled to WebAssembly.

Building

cargo build
cargo test

Restore the upstream C++ reference before doing exact-match validation:

git submodule update --init --recursive

Build and compare against the C++ reference with:

./validate-reference.ps1

You can also run a narrower validation slice by phase, for example:

./validate-reference.ps1 -Phase phase8

This configures and builds cpp-reference/manifold, runs the matching C++ reference tests, and then runs the corresponding Rust tests for the selected phase.

For the WASM demo:

cd demo
bun run build:wasm
bun run dev

Architecture

The port follows the C++ module structure:

Rust module	C++ source	Description
vec / linalg	linalg.h, vec.h	Vector math, linear algebra
polygon	polygon.cpp	2D polygon triangulation
impl	impl.cpp, impl.h	Core mesh data structure
constructors	constructors.cpp	Primitive mesh constructors
boolean3	boolean3.cpp	3D boolean operations
boolean_result	boolean_result.cpp	Boolean output assembly
csg_tree	csg_tree.cpp	CSG tree evaluation
edge_op	edge_op.cpp	Edge manipulation
face_op	face_op.cpp	Face manipulation
smoothing	smoothing.cpp	Smooth normals and subdivision
subdivision	subdivision.cpp	Mesh subdivision
properties	properties.cpp	Mesh properties
sdf	sdf.cpp	SDF-based mesh generation
quickhull	quickhull.cpp	Convex hull
minkowski	minkowski.cpp	Minkowski operations
cross_section	cross_section/	2D cross section

License

Apache-2.0 — matching the original Manifold library.

Credits

• Emmett Lalish — Author of the original Manifold library.
• Lars Brubaker — Port author.
• MatterHackers — Sponsor.