Project CHRONO

Distributed under a permissive BSD license, Chrono is an open-source multi-physics package used to model and simulate:

• dynamics of large systems of connected rigid bodies governed by differential-algebraic equations (DAE)
• dynamics of deformable bodies governed by partial differential equations (PDE)
• granular dynamics using either a non-smooth contact formulation resulting in differential variational inequality (DVI) problems or a smooth contact formulation resulting in DAEs
• fluid-solid interaction problems whose dynamics is governed by coupled DAEs and PDEs
• first-order dynamic systems governed by ordinary differential equations (ODE)
• sensors (camera, LiDAR, GPS, IMU, SPAD) to support simulation in robotics and autonomous agents via a ROS2 interface

Chrono provides a mature and stable code base that continues to be augmented with new features and modules. The core functionality of Chrono provides support for the modeling, simulation, and visualization of rigid and flexible multibody systems with additional capabilities offered through optional modules. These modules provide support for additional classes of problems (e.g., granular dynamics and fluid-solid interaction), modeling and simulation of specialized systems (such as ground vehicles and robots), co-simulation, run-time visualization, post-processing, interfaces to external linear solvers, or specialized parallel computing algorithms (multi-core, GPU, and distributed) for large-scale simulations.

Used in many different scientific and engineering problems by researchers from academia, industry, and federal government, Chrono has mature support for multibody dynamics, finite element analysis, granular dynamics, fluid-solid interaction, ground vehicle simulation, robotics, embodied AI, and terramechanics.

Implemented almost entirely in C++, Chrono also provides Python and C# APIs. The build system is based on CMake. Chrono is platform-independent and is actively tested on Linux, Windows, and MacOS using a variety of compilers.

• Project website
• Build and install instructions

Documentation

• C++ API reference
  • Main development branch
  • Release 10.0.0
  • Release 9.0.0
• Python interface
  • PyChrono
• AMD GPUs (ROCm) — Chrono on AMD GPUs (ROCm) (CPU PyChrono vs HIP/FSI, CMake hints, ROCR_VISIBLE_DEVICES)
• Reference manuals
  • Core module
  • Chrono::Vehicle module

Agent Guidance

If you are using a coding agent to work with this repository, see AGENTS.md. It describes the recommended workflow for both Chrono developers and external users, including build setup, template projects, module manuals, demos, and contribution expectations. If you use Claude locally, the recommended setup is to create a local symlink instead of a copy:

ln -s AGENTS.md CLAUDE.md

Support

• Google Groups user forum

Note on Chrono repository structure

The structure of the Chrono git repository was changed as follows:

• The main development branch is now called main (previously develop)
• The master branch, now obsolete, was deleted
• Releases are located in branches named release/*.* and have tags of the form *.*.*