> ## Documentation Index
> Fetch the complete documentation index at: https://dadd.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# useGravityCompensation

> Apply gravity compensation torques

Applies gravity compensation each frame by adding `qfrc_bias` to `qfrc_applied`. This allows joints to hold their position against gravity without active control.

## Signature

```tsx theme={null}
useGravityCompensation(enabled?: boolean): void
```

## Usage

```tsx theme={null}
import { useGravityCompensation } from "mujoco-react";

function GravCompRobot() {
  useGravityCompensation(true);
  return null;
}
```

### Toggle via State

```tsx theme={null}
function Controls() {
  const [gravComp, setGravComp] = useState(true);
  useGravityCompensation(gravComp);

  return (
    <button onClick={() => setGravComp(!gravComp)}>
      Gravity Comp: {gravComp ? "ON" : "OFF"}
    </button>
  );
}
```

## How It Works

Each physics frame (via `useBeforePhysicsStep`):

```tsx theme={null}
for (let i = 0; i < model.nv; i++) {
  data.qfrc_applied[i] += data.qfrc_bias[i];
}
```

`qfrc_bias` contains the passive forces (gravity, Coriolis, centrifugal) computed by MuJoCo. Adding these to `qfrc_applied` exactly cancels gravity, making the robot behave as if it's weightless.

## When to Use

* **IK gizmo interaction**: Prevents the arm from collapsing when you drag the end-effector
* **Teleoperation**: Lets the operator focus on desired motion without fighting gravity
* **Testing**: Isolate control issues from gravity effects

## Notes

* Also available as a prop on `MujocoCanvas`: `<MujocoCanvas gravityCompensation />`
* Composes correctly with other `useBeforePhysicsStep` hooks since the provider zeros `qfrc_applied` first and all hooks add to it
* This is different from `api.setGravity([0, 0, 0])` which removes gravity for all bodies. Gravity compensation only affects actuated joints.