manifold-csg

Safe Rust bindings to the manifold3d geometry kernel for constructive solid geometry (CSG).

manifold3d is a fast, robust C++ library for boolean operations on 3D triangle meshes. These bindings make its capabilities accessible from Rust with minimal overhead and without requiring users to manage C pointers or memory. See the upstream documentation for details on the underlying algorithms and behavior.

What's included

manifold-csg-sys provides raw FFI bindings to the manifold3d C API. If you need direct C-level control, it's there.

manifold-csg wraps the most commonly needed operations in safe Rust:

• 3D solids (Manifold) — primitives (cube, sphere, cylinder, tetrahedron), boolean operations (union, difference, intersection), transforms, convex hull, decomposition, Minkowski sum/difference, mesh refinement, smoothing, SDF level sets, warp deformation, and OBJ I/O
• 2D regions (CrossSection) — primitives (square, circle, polygons), boolean operations, Clipper2-based geometric offset, convex hull, transforms, warp, and simplification
• Mesh data (MeshGL64 / MeshGL) — f64 and f32 mesh types for getting data in and out
• Triangulation (triangulate_polygons) — constrained Delaunay triangulation of 2D polygons
• 2D-to-3D — extrude (with optional twist and scale) and revolve cross-sections into solids; slice solids back to cross-sections

See API_COVERAGE.md for a full table mapping every C API function to its safe wrapper (or noting where one doesn't exist yet).

Design choices

• f64 by default. Mesh I/O uses MeshGL64 so you don't lose precision through f32 round-trips. f32 paths (from_mesh_f32, to_mesh_f32, MeshGL) are available when you need them.
• Send + Sync. All types can be moved across threads and shared for concurrent reads.
• Automatic memory management. All C handles are freed via Drop. No manual cleanup needed.
• Operator overloads. &a + &b (union), &a - &b (difference), &a ^ &b (intersection) work on both Manifold and CrossSection.
• Callback-based APIs wrapped safely. warp, set_properties, from_sdf, and OBJ I/O all accept closures with catch_unwind to prevent panics from unwinding through C stack frames.
• C API parity. Parameter order and names follow the C API so users transitioning from C/C++ find things where they expect.

Quick start

use manifold_csg::{Manifold, CrossSection, JoinType};

// 3D: drill a cylindrical hole through a cube
let cube = Manifold::cube(20.0, 20.0, 20.0, true);
let hole = Manifold::cylinder(30.0, 5.0, 5.0, 32, false);
let result = &cube - &hole;
assert!(result.volume() < cube.volume());

// 2D -> 3D: offset a rectangle and extrude it
let section = CrossSection::square(10.0, 10.0, true);
let expanded = section.offset(2.0, JoinType::Round, 2.0, 16);
let solid = expanded.extrude(20.0);

See the examples/ directory for more complete, runnable examples.

Crates

Build requirements

• Rust 1.85+
• git, cmake, a C++ compiler
• First build clones manifold3d and compiles it from source; subsequent builds use the cached copy. Internet access is required for the initial clone.

cargo build           # builds both crates
cargo test --features nalgebra   # runs the test suite

Tested on Linux, macOS, and Windows.

Feature flags

Documentation

• API_COVERAGE.md — maps every manifold3d C function to its safe wrapper, with source links
• docs.rs — generated API docs
• examples/ — runnable code examples
• Upstream docs — manifold3d C++ API documentation (helpful for understanding parameter semantics)

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.