OxiPhysics — Unified Pure-Rust Physics Engine

OxiPhysics is a unified, pure-Rust physics engine targeting the same problem domains as Bullet (rigid body), OpenFOAM (CFD), LAMMPS (molecular dynamics), and CalculiX (FEM) — with no C or Fortran dependencies, no unsafe surprises, and strict Rustdoc enforcement.

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Implementation Status — v0.1.0 (2026-04-06)

Crate	Status	Tests	Domain summary
oxiphysics-core	Alpha	5,348	Math, numerics, ODE, stochastic, tensors, signal processing, 80+ modules
oxiphysics-geometry	Alpha	3,089	Shapes, meshes, computational geometry, NURBS, CSG, 57+ modules
oxiphysics-collision	Alpha	2,439	GJK/EPA, SAP, BVH, CCD, ray casting, contact graphs
oxiphysics-materials	Alpha	4,486	Material models, hyperelastic, composites, biomaterials, smart materials
oxiphysics-fem	Alpha	4,561	Linear+nonlinear FEM, XFEM, spectral, stochastic FEM, 124 source files
oxiphysics-gpu	Alpha	2,740	CPU-fallback compute backend, ParticleSystem, parallel sort
oxiphysics-io	Alpha	4,849	VTK, PDB, LAMMPS, OpenFOAM, GLTF, HDF5, 80+ format modules
oxiphysics-lbm	Alpha	5,313	LBM D3Q19/D3Q27, MRT, multiphase, MHD, biofluid, traffic
oxiphysics-md	Alpha	5,139	MD forcefield, QM/MM, REMD, free energy, LAMMPS/AMBER compat
oxiphysics-sph	Alpha	4,367	WCSPH, IISPH, DFSPH, PCISPH, free surface, multiphase SPH
oxiphysics-rigid	Alpha	3,810	Rigid body dynamics, aerospace, spacecraft, marine, swarm
oxiphysics-softbody	Alpha	3,469	PBD, XPBD, cloth, hair, ropes, Cosserat rods, surgical sim
oxiphysics-constraints	Alpha	2,173	PGS/TGS solvers, joints, motors, islands, trajectory opt
oxiphysics-vehicle	Alpha	2,669	Vehicle dynamics, Pacejka tires, EV, autonomous driving
oxiphysics-viz	Alpha	4,072	CPU software renderer, scientific plotting, volume rendering, VR
oxiphysics-python	Partial	788	JSON/serde bridge API (no PyO3 FFI dep yet)
oxiphysics-wasm	Partial	826	JSON/serde bridge API (no wasm-bindgen dep yet)
oxiphysics	top-level re-exports	—	Single-crate entry point for all modules

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Highlights

• Zero stubs — no todo!() or unimplemented!() calls anywhere in the workspace.
• ~60,189 tests across 17 crates, all passing under cargo nextest.
• Strict docs — RUSTDOCFLAGS='-D warnings' cargo doc passes with no missing-docs warnings.
• Pure Rust — zero C/Fortran build-time dependencies; default features are 100% Rust.
• cargo publish --dry-run passes for the top-level oxiphysics crate.

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Features

What is already implemented in each domain:

• Core math & numerics — Vec3, Quat, Mat3, Transform, AABB; ODE integrators (RK4, Dormand-Prince, Rosenbrock); stochastic processes; signal processing (FFT, wavelets, filtering); tensors; sparse linear algebra; interval arithmetic; automatic differentiation; optimization (BFGS, NLP, convex).
• Geometry — Sphere, Box, Capsule, Cylinder, ConvexHull, TriangleMesh, NURBS surfaces/curves, CSG Boolean operations; mesh repair; computational geometry (Delaunay, Voronoi, convex hull); spatial indexing.
• Collision detection — GJK + EPA narrow phase; sweep-and-prune (SAP) broad phase; BVH (AABB tree); CCD (continuous collision detection); ray/segment casting; contact manifold generation; contact graphs.
• Rigid body dynamics — RK4/symplectic integrators; inertia tensor computation; island detection; sleeping; aerospace (attitude control, orbital mechanics); spacecraft; marine hydrodynamics; swarm robotics.
• Constraint solvers — PGS and TGS iterative solvers; hinge, ball-socket, slider, fixed, prismatic joints; motors; trajectory optimisation; warm starting.
• Vehicle dynamics — Pacejka magic-formula tires; suspension kinematics; multi-gear drivetrain; electric vehicle (EV) powertrain; autonomous driving plant model.
• SPH fluids — WCSPH, IISPH, DFSPH, PCISPH kernels; free-surface tracking; multiphase; viscosity; surface tension; neighbour search (spatial hash, KD-tree).
• Lattice Boltzmann (LBM) — D3Q19 and D3Q27 lattices; SRT, MRT, TRT collision operators; turbulence (Smagorinsky); biofluid; magnetohydrodynamics (MHD); traffic flow.
• Finite Element Method (FEM) — linear and nonlinear (hyperelastic, elasto-plastic) FEM; XFEM crack propagation; spectral elements; stochastic FEM (PCE); CalculiX-compatible I/O; tetrahedral and hexahedral elements.
• Molecular Dynamics (MD) — Lennard-Jones, Buckingham, Morse, and custom pair potentials; ReaxFF reactive force field; QM/MM coupling; REMD; free energy perturbation; LAMMPS and AMBER file compatibility.
• Soft body — mass-spring; PBD (position-based dynamics); XPBD; cloth with self-collision; hair simulation; Cosserat elastic rods; surgical simulation model.
• Materials — hyperelastic (Neo-Hookean, Mooney-Rivlin, Ogden); elasto-plastic (von Mises, Drucker-Prager); composite laminates; biomaterials; shape-memory alloys; piezoelectric.
• GPU/compute backend — CPU-fallback work-stealing scheduler; parallel radix sort; particle system; pipeline for SPH and LBM kernels; ready for future GPU back-ends.
• I/O — VTK XML/legacy; PDB/mmCIF; LAMMPS dump; OpenFOAM; GLTF 2.0; HDF5; JSON/MessagePack checkpointing; 80+ format modules.
• Visualization — CPU software rasteriser; Phong + PBR shading; isosurface extraction (Marching Cubes); volume rendering; scientific line/scatter/contour plots; VR-ready camera rigs.

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Crate Overview

Crate	Public Items	Primary purpose
oxiphysics-core	5,876	Foundational math, traits, numerics
oxiphysics-materials	6,241	Material model library
oxiphysics-md	6,343	Molecular dynamics engine
oxiphysics-io	5,978	Data I/O and format converters
oxiphysics-lbm	5,649	Lattice Boltzmann CFD
oxiphysics-fem	5,273	Finite element solver
oxiphysics-viz	5,229	Visualization and rendering
oxiphysics-sph	5,066	Smoothed-particle hydrodynamics
oxiphysics-rigid	4,815	Rigid body dynamics
oxiphysics-softbody	4,524	Soft body / cloth / rods
oxiphysics-vehicle	3,171	Vehicle dynamics
oxiphysics-constraints	3,118	Constraint and joint solvers
oxiphysics-geometry	3,245	Shape and mesh primitives
oxiphysics-gpu	2,748	Compute backend
oxiphysics-collision	2,625	Collision detection
oxiphysics-wasm	1,276	WASM bridge API
oxiphysics-python	1,200	Python bridge API

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Installation

Add to your Cargo.toml:

[dependencies]
oxiphysics = "0.1.0"

Or use individual sub-crates for smaller build graphs, e.g.:

[dependencies]
oxiphysics-core = "0.1.0"
oxiphysics-collision = "0.1.0"
oxiphysics-rigid = "0.1.0"

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Quick Start

use oxiphysics::core::math::Vec3;
use oxiphysics::core::Transform;

// Build a transform at a given position
let origin = Transform::default();
let offset = Vec3::new(1.0, 2.0, 3.0);

// Transform a point from local space into world space
let world_pt = origin.transform_point(&offset);
println!("world: {:?}", world_pt);

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Building from Source

cargo build --release
cargo nextest run --all-features
cargo clippy --all-features --all-targets
RUSTDOCFLAGS='-D warnings' cargo doc --all-features --no-deps

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License

Apache-2.0. Copyright 2026 COOLJAPAN OU (Team KitaSan).