# Using URDF Files in Vuer

## Overview

Vuer enables loading URDF (Unified Robot Description Format) files for robotics visualization. The framework supports mesh files in `.dae`, `.stl`, `.obj`, and `.ply` formats.

## Basic Implementation

The code example demonstrates loading URDF models:

```python
from asyncio import sleep
from vuer import Vuer, VuerSession
from vuer.schemas import Urdf

app = Vuer()

@app.spawn(start=True)
async def main(proxy: VuerSession):
    proxy.upsert @ Urdf(
        src="https://docs.vuer.ai/en/latest/_static/perseverance/rover/m2020.urdf",
        jointValues={},
        rotation=[3.14 / 2, 0, 0],
        position=[0, 0, -1.5],
        key="perseverance",
    )

    # Keep the session alive
    while True:
        await sleep(1.0)

app.run()
```

## Key Parameters

### src
URL path to the URDF file. Can be a local path or remote URL.

### jointValues
Dictionary for joint configuration. Use empty `{}` for default joint positions.

Example with joint values:
```python
jointValues={
    "joint_1": 0.5,
    "joint_2": -0.3,
    "knee_joint": 1.2,
}
```

### rotation
Euler angles `[x, y, z]` for model orientation in radians.

### position
3D coordinates `[x, y, z]` for model placement.

### key
Unique identifier for the model. Used for updates and removal.

## Supported Mesh Formats

Vuer supports URDF files with mesh files in the following formats:
- `.dae` (COLLADA)
- `.stl` (STereoLithography)
- `.obj` (Wavefront OBJ)
- `.ply` (Polygon File Format)

## Complete Example with Multiple Robots

```python
from asyncio import sleep
from vuer import Vuer, VuerSession
from vuer.schemas import Urdf, Scene, AmbientLight

app = Vuer()

@app.spawn(start=True)
async def main(session: VuerSession):
    session.set @ Scene(
        # Add lighting
        AmbientLight(intensity=1.0),

        # Load first robot
        Urdf(
            src="/static/robots/robot1.urdf",
            position=[0, 0, 0],
            rotation=[0, 0, 0],
            key="robot-1",
        ),

        # Load second robot
        Urdf(
            src="/static/robots/robot2.urdf",
            position=[2, 0, 0],
            rotation=[0, 0, 0],
            key="robot-2",
        ),
    )

    # Keep the session alive
    while True:
        await sleep(1.0)

app.run()
```

## Serving Local URDF Files

To serve URDF files from your local filesystem:

```python
from vuer import Vuer

# Point to the directory containing your URDF files
app = Vuer(static_root="path/to/urdf/directory")

@app.spawn(start=True)
async def main(session):
    session.upsert @ Urdf(
        src="/static/my_robot.urdf",  # Relative to static_root
        position=[0, 0, 0],
        key="my-robot",
    )

    while True:
        await sleep(1.0)

app.run()
```

## Source

Documentation: https://docs.vuer.ai/en/latest/tutorials/robotics/urdf.html