Rumoca Website

The official website for Rumoca, an open-source Modelica compiler written in Rust. The site is a pure frontend static application -- no backend server required.

What's on the site

• Home -- overview of Rumoca's capabilities and compiler pipeline
• Tutorials -- 27 interactive tutorials covering ODE modeling, 3D visualization, control systems, optimization, and code generation workflows. Each tutorial runs the Rumoca compiler in your browser via WebAssembly.
• Simulation -- real-time flight simulation page where you can fly aircraft in 3D environments using keyboard or gamepad input. Supports two modes:
  • WASM Controller -- physics and controller run entirely in the browser (no external dependencies)
  • Autopilot (SIL) -- browser runs the plant physics, connected to a real autopilot binary (e.g. Cerebri2) through a WebSocket-to-UDP proxy
• Playground -- browser-based Modelica editor with compilation, simulation, and code generation

Simulation page features

• Three environments: Desert, Forest, Arctic
• Two aircraft: Quadrotor (high-fidelity 3D model) and Fixed Wing (Sport Cub with animated control surfaces)
• Gamepad support (auto-detected, takes priority over keyboard)
• Keyboard controls: WASD for pitch/roll, arrows for throttle/yaw, Space to arm, R to reset

Development

Requires Node.js >= 22.12.0.

npm install
npm run dev       # dev server at localhost:4321
npm run build     # static build to dist/

WASM dependencies

The site uses two WASM modules in public/wasm/:

• rumoca.js / rumoca_bg.wasm -- the Rumoca compiler (for tutorials and playground)
• rumoca_bind_wasm.js / rumoca_bind_wasm_bg.wasm -- includes WasmStepper for real-time simulation

Run npm run sync-wasm to sync from a local Rumoca build.

Autopilot (SIL) mode

The simulation page can connect to a locally-running autopilot via a WebSocket-to-UDP proxy. This lets you fly with a real flight controller (like CogniPilot's Cerebri2) while the plant physics run in the browser.

Architecture

Browser (WASM plant)  <--WebSocket-->  Proxy  <--UDP/FlatBuffers-->  Autopilot

The proxy translates between JSON (WebSocket) and FlatBuffers (UDP) using a sil_config.toml file. The proxy is included in this repo at rumoca_ws_proxy/.

Running it

1. Start the autopilot (e.g. Cerebri2 native_sim)

2. Start the WebSocket-to-UDP proxy:

   cd rumoca_ws_proxy
   ./run.sh /path/to/your/sil_config.toml

3. Open the simulation page in your browser and select "Autopilot (SIL)" in the config panel

Controls

Key / Button	Action
Up / Down arrows	Throttle up / down
Left / Right arrows	Yaw
W / S	Pitch forward / back
A / D	Roll left / right
Space	Arm / Disarm
R	Reset simulation
Gamepad Start	Arm / Disarm
Gamepad A	Reset
Gamepad B	Zero sticks

Tech stack

• Astro -- static site generator
• React -- interactive components
• Three.js -- 3D visualization
• uPlot -- plotting
• Tailwind CSS -- styling
• WebAssembly -- Rumoca compiler and real-time simulation in the browser