Unreal Robotics Lab (URLab)

An open-source Unreal Engine 5 plugin that embeds the MuJoCo physics engine for high-fidelity, photorealistic robotics simulation, sim-to-real transfer, and synthetic data generation.

Unreal Robotics Lab (URLab) is an open-source Unreal Engine 5 plugin that embeds the MuJoCo physics engine directly into the editor and runtime, combining Unreal’s photorealistic rendering with MuJoCo’s precision physics. It targets sim-to-real transfer, synthetic data generation, and robot learning workflows that need both visual fidelity and accurate contact dynamics.

Key features

  • MJCF drag-and-drop import – drop a MuJoCo .xml into the Content Browser and URLab builds a full body / joint / actuator / sensor tree as an Articulation Blueprint.
  • Quick Convert – attach UMjQuickConvertComponent to any Static Mesh and it becomes a MuJoCo physics body. No XML required.
  • 40+ sensors, 8 actuator types, 4 joint types – position, velocity, motor, muscle, damper, adhesion, cylinder, general actuators; hinge, slide, ball, free joints; accelerometer, gyro, force/torque, touch, rangefinder, frame tracking, cameras.
  • ZMQ networking – stream sensor data out, receive actuator commands in, drive the simulator from Python, ROS 2, or any ZMQ-speaking process.
  • Python policy bridge – companion package urlab_bridge for remote control, RL policy deployment, and ROS 2 bridging.
  • Record and replay – capture trajectories, replay frame by frame, CSV import, snapshot and restore full simulation state.
  • MjSimulate dashboard – in-editor widget with physics parameter tuning, actuator sliders, sensor readouts, live camera feeds.
  • Keyframe system, possession, cinematic tools, CoACD convex decomposition, heightfield terrain from Unreal Landscape – see the docs for the complete feature list.

When to use URLab

  • You need photorealistic rendering with accurate contact physics (sim-to-real transfer, synthetic data generation).
  • You want to control MuJoCo robots from Python or ROS 2 while rendering in Unreal Engine.
  • You want Unreal’s ecosystem (Blueprints, Sequencer, Marketplace assets, Niagara) with physics-accurate robots.

Requirements

Unreal Engine 5.7+, Windows (Linux experimental), MuJoCo 3.7+ (bundled), Visual Studio 2022, CMake 3.24+. See the Getting Started guide for a full walkthrough.

Citation

If URLab supports your research, please cite the ICRA 2026 paper:

@inproceedings{embleyriches2026urlab,
  title     = {Unreal Robotics Lab: A High-Fidelity Robotics Simulator with Advanced Physics and Rendering},
  author    = {Embley-Riches, Jonathan and Liu, Jianwei and Julier, Simon and Kanoulas, Dimitrios},
  booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},
  year      = {2026},
  url       = {https://arxiv.org/abs/2504.14135}
}

Unreal Robotics Lab is an independent software plugin. It is NOT affiliated with, endorsed by, or sponsored by Epic Games, Inc. “Unreal” and “Unreal Engine” are trademarks of Epic Games, Inc.

References