Open-source alternatives to Rapier

mujoco_menagerie is a curated library of physical robot specifications and XML model definitions designed for standardized dynamics and contact simulation. It provides a collection of high-quality robot model files for humanoids, quadrupeds, and manipulators, alongside detailed kinematic and inertial parameters used to reproduce real-world robot behavior in virtual environments. The project serves as a repository of robotics simulation assets and MJCF model definitions optimized for accuracy. It includes standardized model libraries specifically for bipedal, quadrupedal, and humanoid hardware

Box2D is a 2D physics engine and rigid body simulator designed to compute collisions, forces, and joints in a two-dimensional plane. It functions as a collision detection library and a constraint-based physics solver that calculates the movement and interaction of solid objects using mass, friction, and restitution properties. The engine ensures consistency across different hardware architectures through a deterministic trigonometry implementation. It prevents high-speed objects from passing through boundaries using continuous collision detection and time-of-impact interpolation. The system

Avian is a 2D physics engine and rigid body dynamics simulator designed to calculate physical motion using mass, forces, and velocity. It provides a framework for simulating rigid body dynamics, collision detection, and joint constraints for games and applications. The engine utilizes a modular physics pipeline with a plugin-based architecture, allowing for the customization of simulation fidelity settings and the extension of collision backends. It includes a specialized kinematic character controller for implementing entity movement and sliding behavior against physical geometry. The syste

This repository is a comprehensive collection of functional 2D and 3D demo projects and implementation samples for the Godot Game Engine. It serves as an interactive tutorial and reference library, providing a working codebase to demonstrate how to apply engine features in real-world scenarios. The collection focuses on practical implementation guides, covering a wide array of technical capabilities from basic engine fundamentals to advanced rendering and scripting techniques. It allows users to study the application of node-based composition, asset pipelines, and game logic through direct ex

Bullet3 is a professional physics simulation engine designed for calculating rigid body, soft body, and collision dynamics within 3D environments and robotics applications. It functions as a computational framework for determining complex geometric intersections and contact manifolds between objects in simulated space. The library distinguishes itself through a distributed rendering framework that scales heavy graphical workloads and scene generation tasks across large clusters of machines. This capability enables the production of massive datasets by distributing complex scene generation acr

PhysicsJS is a JavaScript physics engine and 2D rigid body simulator designed to calculate the collisions, constraints, and dynamics of physical bodies. It functions as a modular physics library for simulating the movement and interaction of circular bodies and convex polygons. The engine implements constraint-based dynamics to enforce distance and angle constraints between objects, enabling the creation of articulated structures and linked physics. It utilizes impulse-based resolution to handle collisions and prevent objects from passing through one another. The library provides capabilitie

Pinocchio is a multi-body dynamics engine and rigid body physics library designed for computing forward and inverse kinematics and dynamics for articulated rigid-body systems. It functions as a robot kinematics solver and model parser, enabling the analysis of complex robotic systems through kinematic and dynamic computations. The project distinguishes itself with specialized capabilities for constrained dynamics, including the calculation of contact impulses and centroidal momentum. It provides a parallel processing collision detection system for computing minimal distances between rigid bod

ammo.js is a JavaScript port of the Bullet physics engine, compiled via Emscripten to provide a high-performance physics library for the browser. It functions as a 3D rigid body engine and an Emscripten compiled library that enables complex physical computations using WebAssembly and JavaScript. The project provides specialized simulation capabilities for soft body physics, modeling the deformation of flexible materials like cloth and rubber, and a vehicle dynamics engine for calculating the mechanics of wheeled vehicles. The simulation surface also covers rigid body dynamics for non-deforma

Cyclone Physics is a three-dimensional rigid body physics engine designed for game development. It provides a framework for simulating the motion, rotation, and physical interactions of solid objects by applying fundamental laws of mechanics. The library utilizes discrete time integration to update object positions and velocities across fixed intervals. It manages complex scenes through a bounding volume hierarchy and employs impulse-based collision resolution to maintain momentum during contact. To handle simultaneous interactions, the engine uses an iterative velocity solver that repeatedly

Urho3D is a cross-platform 3D game engine written in C++. It uses a component-based scene graph to compose game objects from nodes and attached components, separating transforms from behaviors for modular design. The engine integrates AngelScript and Lua scripting for game logic, uses the Bullet library for physics simulation, and renders scenes with OpenGL or Direct3D through forward, deferred, or light pre-pass pipelines with customizable render passes and shadow mapping. The engine distinguishes itself with a built-in visual scene and UI editor for composing 3D worlds and interface layouts

planck.js is a 2D rigid body physics engine for JavaScript and HTML5, based on Box2D. It provides a framework for simulating physical interactions and calculating the motion of solid objects within a two-dimensional virtual environment. The engine is designed for cross-platform web gaming, enabling the implementation of rigid body dynamics across different web browsers and devices. The library manages simulation through a constraint-based physics solver and rigid body state management. It utilizes iterative impulse resolution, semi-implicit Euler integration, and dynamic AABB tree partitioni

LibGDX is a Java-based framework designed for cross-platform game development, enabling the creation and deployment of 2D and 3D games across desktop, mobile, and web environments from a single codebase. It functions as a comprehensive library that abstracts hardware-accelerated graphics, audio, input, and file system access, providing a unified interface for developers to manage game logic and application lifecycles. The framework distinguishes itself through a high-performance architecture that prioritizes efficiency and native interoperability. It utilizes a batch-oriented graphics pipelin

Space Station 14 is a C# multiplayer game and roleplay simulation framework. It is built upon an Entity-Component-System (ECS) game engine that separates logic into systems and data into components to manage complex entity interactions. The project functions as a grid-based physics simulator with a YAML data-driven prototype system for defining game objects. The project features a specialized 2D sprite rendering engine that maps server-side appearance data to client-side shaders. It implements a networking model with client-side prediction and dirty-flagged state synchronization to reduce inp

Webots is a physics-based robot simulator and development environment used for modeling, programming, and testing the behavior of robots in a simulated 3D physical world. It serves as a virtual prototyping tool to verify mechanical and electronic systems through the creation of virtual robot models and control logic. The platform enables a full robotics simulation workflow, including the development of robot controllers and the programming of autonomous agent behaviors. It focuses on physical system modeling to represent the mechanical properties of hardware and simulate real-world interactio

Stride is a C# game engine and 3D rendering engine used for building three-dimensional games and virtual reality applications. It functions as a comprehensive framework and development kit for creating immersive experiences within a managed code environment. The project includes a developer GUI framework for building internal debugging tools and utility panels. It also serves as a 3D physics simulator for calculating rigid body dynamics and collision detection within a scene. The engine covers environmental scene rendering and project scaffolding workflows. It provides tooling for game devel

This project is a WebGL 3D game engine and comprehensive suite of tools for rendering high-performance 3D graphics and interactive scenes in the browser using WebGL and WebGPU. It provides a dedicated WebXR framework for building augmented and virtual reality experiences that run directly in a web browser. The engine includes a specialized Gaussian splatting renderer for displaying 3D point-cloud data to create photorealistic environmental captures. It utilizes a glTF asset pipeline to load and stream compressed 3D models and textures for efficient asset delivery. The system covers real-time

Habitat-sim is a high-performance 3D simulation platform designed for training and benchmarking embodied AI agents within photorealistic indoor and outdoor environments. It serves as a simulator for AI and robotics, providing a system for generating synthetic data and simulating physical interactions. The project is distinguished by a native C++ core that enables high-throughput simulation and a rendering pipeline using physically based rendering and baked global illumination. It features a navigation system based on pre-computed navigation meshes to ensure collision-free traversal and a rigi

MathUtilities is a collection of specialized toolkits providing engines for geometry, computer vision, mathematics, physics simulation, and signal processing. It functions as a comprehensive mathematics and physics library focused on linear algebra, numerical optimization, and geometric calculations for technical applications. The project distinguishes itself through a physics simulation toolkit and a 3D geometry engine. These provide capabilities for Verlet integration, iterative inverse kinematics solvers, distance field rendering via volumetric raymarching, and mesh geometry deformation. I

Newton is a GPU-accelerated physics engine and robotics simulation platform designed for high-performance modeling of rigid bodies and complex articulations. It functions as a differentiable physics engine, calculating gradients to enable mathematical optimization and machine learning. The platform is distinguished by its ability to execute multiple parallel physics worlds on a single GPU, which accelerates data collection for reinforcement learning. It also supports the simulation of deformable bodies, such as cloth and cables, using particle-based methods and multi-physics coupling. Newton

melonJS is a lightweight HTML5 game engine for building 2D games in the browser using JavaScript. It provides a complete framework for sprite animation, tilemap loading, physics simulation, input handling, and audio playback, with a unified rendering system that automatically switches between WebGL and Canvas2D backends without code changes. The engine distinguishes itself through several integrated capabilities. It features a per-sprite shader pipeline for custom fragment shader effects, a SAT-based collision engine with swappable physics adapters (including built-in SAT, Matter.js, and Plan

Chrono is a multi-physics simulation suite that functions as a multibody dynamics simulator, a finite element analysis tool, and a robotics simulation framework. It provides specialized solvers for fluid-solid interaction and distributed physics engines capable of synchronizing multiple agents across a network. The project features a dedicated pipeline for converting CAD assemblies into simulation-ready formats and integrates directly with robot operating systems to validate autonomous control logic and sensors. It differentiates itself through the use of WebAssembly for portable browser-base

Orillusion is a WebGPU 3D rendering engine designed for high-fidelity scenes and visual effects in the browser. It functions as a GPU compute framework for parallel mathematical operations and a physically-based rendering graphics pipeline for realistic materials and surfaces. The system also includes a web-based 3D animation toolkit for driving skeletal animations and interpolating vertex positions. The engine is distinguished by its use of an entity component system for scene logic and a macro-based shader generation system that creates multiple shader variants. It optimizes performance thr

Drake is a robotics simulation framework and control system modeling tool used for designing, simulating, and verifying the dynamics of complex robotic systems. It functions as a multibody dynamics simulator and a mathematical optimization library, providing a suite of algorithms for trajectory optimization and the simulation of articulated robots. The framework is distinguished by its block-diagram system for composing dynamical subsystems and its ability to formulate and solve diverse mathematical programs, including linear, quadratic, and nonconvex nonlinear problems. It supports specializ

Flame is a 2D game engine and framework for Flutter. It provides a component-based architecture to organize scene entities and manage their lifecycles through a structured hierarchy of game objects, coordinated by a consistent game loop. The engine includes a graphics library for rendering animated sprites, particle effects, and external textures. It features a 2D physics integration layer that supports rigid body dynamics and collision detection between entities. The framework covers additional capabilities for game engineering, including user input capture for gestures and gamepads, audio

jetson-inference is a set of libraries and tools for executing optimized deep learning models on embedded GPU hardware. Its primary purpose is to enable real-time computer vision and AI inference at the edge with low latency and high throughput. The project distinguishes itself through high-performance streaming analytics and the ability to execute concurrent AI pipelines on auto-grade silicon. It provides specialized support for multi-sensor stream processing, utilizing zero-copy data transport to load camera frames directly into GPU memory. The codebase covers a broad surface of capabiliti

This repository is a collection of reference implementations and sample projects demonstrating data-oriented design using the Unity Entities package. It provides a suite of examples for implementing an entity component system that separates game data into components and logic into systems. The collection includes specialized demonstrations for rendering large volumes of entities via graphics pipelines, implementing high-performance collision and rigid body dynamics through data-oriented physics, and managing multiplayer state synchronization using the network framework for entities. It also p

cocos2d-iphone is a framework for 2D game development and the creation of two-dimensional graphical applications. It enables cross-platform development for iOS and macOS using Objective-C and high-performance graphics rendering. The project provides tools for building interactive environments, including the creation of orthogonal, isometric, or hexagonal tile-based maps. It supports the implementation of rigid body dynamics and collision detection through a 2D physics simulation system. The framework covers a broad range of capabilities, including sprite-based rendering, audio playback manag