Run MuJoCo + 3DGS in your Browser.

Load and Run MuJoCo 3.3.8 Models using JavaScript and the official MuJoCo WebAssembly Bindings.

Features

• MuJoCo 3.3.8 WebAssembly: MuJoCo running entirely in the browser, works on any devices, even your phone.

• Hybrid Rendering: Combine MuJoCo with photorealistic 3D Gaussian Splatting scenes, with physics objects correctly occlude and interact with 3DGS environments

• Toggle Mode: Switch between pure physics rendering and hybrid 3DGS+physics mode

• Mouse Interaction: Click and drag any physics object in the scene

• Keyboard teleop: End-effector teleop controller for SO101 (analytical) and Franka Panda (numerical, SGD)

• RL policy: Run 10+ pretrained policies on Unitree G1

• Import any robot: By uploading the whole folder

  • The folder should only contain a single .xml, along with /assets folder
  • Find available robots at MuJoCo Menagerie)

• Import any scene: use any 3DGS scene you want
  • .spz file, recommend: Marble from World Labs
  • If you only upload the .spz file, there will not be any collision other than the floor
  • You can add a 3DGS scene along with an .xml file for collision setup

Easiest way to find collision boxes' coordinate: adding boxes in the studio in Marble and give the bounding boxes info to AI to generate a collision.xml

🤖 Supported Robots (& keyboard control)

XLeRobot - Dual-Arm Mobile Manipulator

• DOF: 2 (base) + 10 (dual 5-DOF arms) + 2 (grippers) + 2 (head)
• Control Method: Inverse kinematics with keyboard teleoperation
• Actuators: STS3215 servos (SO-Arm101 specification)
• Keyboard Mapping:
  • Base: W/S (forward/backward), A/D (turn)
  • Left arm: 7/Y (rotation), 8/U (EE Y), 9/I (EE X), 0/O (pitch), -/P (wrist roll)
  • Right arm: H/N (rotation), J/M (EE Y), K/, (EE X), L/. (pitch), ;// (wrist roll)
  • Grippers: V (left), B (right)
  • Head: R/T (pan), F/G (tilt)
  • Reset: X

SO101 - Single-Arm Manipulator

• DOF: 6 (shoulder rotation, shoulder pitch, elbow, wrist pitch, wrist roll, gripper)
• Control Method: 2-link inverse kinematics
• Actuators: STS3215 servos with high-precision position control
• Keyboard Mapping:
  • Shoulder: A/D (rotation)
  • End effector: W/S (Y axis), Q/E (X axis)
  • Orientation: R/F (pitch adjustment)
  • Wrist: Z/C (roll)
  • Gripper: V (toggle)
  • Reset: X

Franka Emika Panda - 7-DOF Research Arm

• DOF: 7 (redundant arm) + 2 (parallel gripper)
• Control Method: Damped Least Squares inverse kinematics with gravity compensation
• Special Features:
  • 6-DOF pose control (position + orientation)
  • Adaptive damping for stability
  • Multi-iteration IK solver
  • High-force gripper (100N)
• Keyboard Mapping:
  • Position: W/S (X), A/D (Y), Q/E (Z)
  • Orientation: Z/C (roll), R/F (pitch), T/G (yaw)
  • Gripper: V (open), B (close)
  • Reset: X

Humanoid

• DOF: Full humanoid with torso, arms, and legs
• Control Method: Joint-level PD control
• Interaction: Mouse drag support for direct manipulation

JavaScript API

import load_mujoco from "./dist/mujoco_wasm.js";

// Load the MuJoCo Module
const mujoco = await load_mujoco();

// Set up Emscripten's Virtual File System
mujoco.FS.mkdir('/working');
mujoco.FS.mount(mujoco.MEMFS, { root: '.' }, '/working');
mujoco.FS.writeFile("/working/humanoid.xml", await (await fetch("./assets/scenes/humanoid.xml")).text());

// Load model and create data
let model = mujoco.MjModel.loadFromXML("/working/humanoid.xml");
let data  = new mujoco.MjData(model);

// Access model properties directly
let timestep = model.opt.timestep;
let nbody = model.nbody;

// Access data buffers (typed arrays)
let qpos = data.qpos;  // Joint positions
let qvel = data.qvel;  // Joint velocities
let ctrl = data.ctrl;  // Control inputs
let xpos = data.xpos;  // Body positions

// Step the simulation
mujoco.mj_step(model, data);

// Run forward kinematics
mujoco.mj_forward(model, data);

// Reset simulation
mujoco.mj_resetData(model, data);

// Apply forces (force, torque, point, body, qfrc_target)
mujoco.mj_applyFT(model, data, [fx, fy, fz], [tx, ty, tz], [px, py, pz], bodyId, data.qfrc_applied);

// Clean up
data.delete();
model.delete();

🙏 Acknowledgements

This project is built based on mujoco-wasm, sparkjs, and human policy viewer.