Urdf

The Urdf component loads and displays URDF (Unified Robot Description Format) robot models. This is essential for:

• Visualizing robot configurations

• Creating interactive robot simulations

• Displaying joint positions in real-time

• Building robot teleoperation interfaces

Loading URDF from URL

A minimal example that loads a URDF robot model directly from a URL:

from vuer import Vuer
from vuer.schemas import DefaultScene, Urdf, OrbitControls

app = Vuer()

@app.spawn(start=True)
async def main(sess):
    sess.set @ DefaultScene(
Urdf(src="https://raw.githubusercontent.com/nasa-jpl/m2020-urdf-models/main/rover/m2020.urdf"),
        up=[0, 0, -1],  # Z-down coordinate system
        bgChildren=[OrbitControls(key="OrbitControls")]
    )

    await sess.forever()

Loading URDF from Local Files

Load a URDF file from your local file system and animate joint values in real-time:

import os
import math
from asyncio import sleep
from math import pi

from vuer import Vuer, VuerSession
from vuer.schemas import DefaultScene, Movable, OrbitControls, Urdf

# Set up static file serving from the assets directory
app = Vuer(static_root=os.getcwd() + "/../../../assets")

# URDF file path (served via Vuer's static file server)
urdf_path = "robots/mini_cheetah/mini_cheetah.urdf"

# Initial joint configuration for the quadruped robot
initial_joints = {
    "FL_hip_joint": -0.2,
    "RL_hip_joint": -0.2,
    "FR_hip_joint": 0.2,
    "RR_hip_joint": 0.2,
    "FL_thigh_joint": -0.25 * pi,
    "RL_thigh_joint": -0.25 * pi,
    "FR_thigh_joint": -1.3,
    "RR_thigh_joint": -0.25 * pi,
    "FL_calf_joint": 0.5 * pi,
    "RL_calf_joint": 0.5 * pi,
    "FR_calf_joint": 0.6 * pi,
    "RR_calf_joint": 0.5 * pi,
}

@app.spawn(start=True)
async def main(sess: VuerSession):
    # Set up the initial scene with the robot
    sess.set @ DefaultScene(
        Movable(
            Urdf(
                src="http://localhost:8012/static/" + urdf_path,
                jointValues=initial_joints,
                key="robot",
            ),
            position=[0, 0, 0.3],
            scale=0.4,
        ),
        grid=True,
        up=[0, 0, 1],
        bgChildren=[
            OrbitControls(key="OrbitControls"),
        ],
    )

    await sleep(0.1)

    # Animate the front-right leg using sinusoidal motion
    i = 0
    while True:
        # Create animated joint values by modifying FR leg
        animated_joints = initial_joints.copy()
        animated_joints["FR_thigh_joint"] = 0.5 * math.sin(i * 0.1) - 1.3
        animated_joints["FR_calf_joint"] = -0.5 * math.sin(i * 0.1) + 0.6 * pi

        # Update the robot with new joint values
        sess.update @ Urdf(
            src=urdf_path,
            jointValues=animated_joints,
            key="robot",
        )

        await sleep(0.016)  # ~60 FPS
        i += 1

Key Parameters

Parameter	Type	Default	Description
key	str	-	Unique identifier for the robot
src	str	-	URL or path to the URDF file
jointValues	dict	{}	Dictionary mapping joint names to positions (radians)
position	list	[0,0,0]	Robot position in world coordinates
rotation	list	[0,0,0]	Robot rotation (Euler angles)
scale	float/list	1	Uniform or per-axis scale

Supported Mesh Formats

The URDF loader supports the following mesh formats for robot links:

• .dae (Collada)

• .stl (STereoLithography)

• .obj (Wavefront OBJ)

• .ply (Polygon File Format)

Learn More

For detailed examples of using Urdf, see:

• Unitree Go1 with Stairs - Multi-robot scenes with environment