LOTUSim is a real-time, multi-domain simulation platform for maritime operations. It models realistic surface, underwater, and air physics for aerial drones, surface ships, and underwater vehicles. An immersive interface lets human operators run human-autonomous agent scenarios, and physically accurate models make LOTUSim suitable for training AI algorithms.

Quickstart

You need to have Nix setup on your machine (compatible with Linux/macOS). You can install it via this command:

curl --proto '=https' --tlsv1.2 -L https://nixos.org/nix/install | sh -s -- --daemon

For more options, check their official website: Nix.

1. Add the binary caches

Needs root, once per machine. This enables the nix-command and flakes experimental features and adds binary caches so Nix fetches the Gazebo stack and the physics engine prebuilt instead of compiling them locally.

sudo tee -a /etc/nix/nix.conf <<'EOF'
experimental-features = nix-command flakes
extra-substituters = https://ros.cachix.org https://naval-group.cachix.org
extra-trusted-public-keys = ros.cachix.org-1:dSyZxI8geDCJrwgvCOHDoAfOm5sV1wCPjBkKL+38Rvo= naval-group.cachix.org-1:ytTEzFEeuzQrC9IRYLzHGa5OnM65G95M6/sbPd0fy28=
EOF
sudo systemctl restart nix-daemon   # or your init system's equivalent

/etc/nix/nix.conf is the system-wide file, so the keys are trusted for every user and the signatures verify.

2. Install and run:

# Away from NixOS, the window needs a GPU bridge — install it once and `lotusim` finds it by itself:
nix profile add github:nix-community/nixGL#nixGLIntel

nix profile add github:naval-group/LOTUSim github:naval-group/LOTUSim#ui

lotusim run --gui        # the simulation, in a Gazebo window
lotusim-ui               # the browser interface, on http://localhost:8080

On an NVIDIA or hybrid/Optimus machine, also add the NVIDIA bridge so rendering uses the discrete GPU instead of falling back to Intel — this reads your driver's exact version off the running machine, so it needs --impure, and NVIDIA's userspace driver is unfree:

NIXPKGS_ALLOW_UNFREE=1 nix profile add --impure github:nix-community/nixGL#nixGLNvidia

lotusim --help lists the worlds a build carries.

Without installing anything

nix run github:naval-group/LOTUSim -- run --gui
podman run --rm ghcr.io/naval-group/lotusim

The wiki covers worlds and scenarios, the state directory, NVIDIA and hybrid GPUs, and running under a container.

⚡ Jump straight to install ➜ running in under 10 minutes: Getting Started

For full documentation, see the wiki. For issues or questions, please open an issue and we will get back to you asap.

For partnerships or contributing, contact lotusim_support@naval-group.com.

Published under EPL-2.0.

Video

Citation

If you use LOTUSim in your research, please cite:

@inproceedings{LOTUSim26iros,
  title     = {{LOTUSim}: Multi-Domain Simulator for Marine Robotics},
  author    = {Buche, Cedric and Grosset, Juliette and Lechene, Helene and Dubromel, Marie and Havez-Bodivit, Pierig and Neo, Malcom and Prodhon, Julien},
  booktitle = {2026 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
  year      = {2026},
  publisher = {IEEE}
}

See the Publications wiki page for related repositories and papers.