robola 0.2.2

Robola MJCF Editor Local Bridge - Local Python Library for MuJoCo and Online Web mjcf editing

Robola – Local MuJoCo Runtime Companion

RobolaPyLib powers the local runtime that feeds the Robola Web Editor:

• Load and validate MuJoCo MJCF scenes on your own machine
• Stream geometry/material/joint data to the browser in real time
• Expose a WebSocket API for simulation control, saving, and asset transfer

✅ Use the online editor at https://robolaweb.com/editor. The website never touches your disk—the CLI in this repo loads every file locally and only streams the data you approve.

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Installation

From PyPI (recommended)

pip install robola

From source (development)

git clone https://github.com/robola-dev/RobolaPyLib.git
cd RobolaPyLib
pip install -e .

Prerequisites:

• Python 3.10 or later
• MuJoCo 3.3+ (and its license/key environment variables configured if required)

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5-Minute Quickstart

1. Prepare a model – keep an *.xml MJCF file handy (for example ~/robots/spot.xml).
2. Start the local server

   robola serve ~/robots/spot.xml --port 9527
   

   • Serves WebSocket traffic on ws://localhost:9527
   • The terminal banner confirms that the runtime is up
3. Open the online editor – visit https://robolaweb.com/editor and sign in.
4. Connect to the runtime – enter 9527 in the “WebSocket Port” field (top-right) and click Connect.
5. Model, simulate, iterate
   • The editor fetches the local model and renders the scene
   • You can inspect/edit bodies, joints, materials, etc.
   • Start/pause/stop simulations or save back to disk from the browser

📌 Keep the CLI process running while the browser tab is open so the editor can stream frames and send commands.

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Example Models

You can use MJCF models from the MuJoCo Menagerie as examples. Clone the repository and serve any .xml file:

git clone https://github.com/google-deepmind/mujoco_menagerie.git
cd mujoco_menagerie
robola serve ./google_robot/scene.xml 

Then connect to the Robola Web Editor at https://robolaweb.com/editor using port 9527.

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CLI Usage

# Load a model with the default port (9527)
robola serve /path/to/model.xml

# Bootstrap a blank scene and launch the server (path is created from the built-in template before serving)
robola serve /path/to/new_scene.xml --new

# Use a custom port
robola serve /path/to/model.xml --port 9000

# Restrict CORS origins (production)
robola serve /path/to/model.xml --origin https://robolaweb.com

# Tune streaming rate and logging
robola serve /path/to/model.xml --fps 30

Common Options

Option	Description	Default
--port	WebSocket listening port	9527
--origin	Allowed browser origin (CORS)	* (set to https://robolaweb.com when sharing)
--fps	Simulation streaming rate (1–60 Hz)	30
--new	Create the specified MJCF path with the built-in template before serving (fails if the file already exists)	false

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Embedding via Python

from robola import serve

serve(
    mjcf_path="/abs/path/to/model.xml",
    port=9527,
    allowed_origin="https://robolaweb.com",
    fps=30,
)

Call serve() inside a notebook, a script, or your own application to reuse the same local WebSocket protocol that the CLI exposes.

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Troubleshooting

Symptom	Likely cause	Fix
“Unable to connect” in the editor	Port/origin mismatch	Ensure the CLI --port and --origin match the values entered in the editor
Simulation crashes on start	Missing meshes/textures referenced by MJCF	Check the terminal logs and verify every asset path is valid relative to the MJCF file
Saving fails	File not writable	Confirm the XML can be written and that the CLI is still running

⚠️ Current limitation: Robola does not support MuJoCo Flex (soft bodies) or height-field (hfield) based terrain rendering yet. These assets will be ignored/omitted when streaming to the editor.

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License

MIT License. PRs and issues are welcome—help more roboticists build faster with Robola. 🤖🚀