# WheelHit

> Contact information for the wheel, reported by WheelCollider.

## Definition

* **Type:** Struct
* **Namespace:** [UnityEngine](/engine/6000.7/script-reference/unityengine.md)
* **Assembly:** UnityEngine.VehiclesModule

```csharp
public struct WheelHit
```

## Remarks

Friction for the [WheelCollider](/engine/6000.7/script-reference/unityengine/wheelcollider.md) is computed separately from the rest of the physics, using a slip based tire friction model. This allows for more realistic behaviour, but makes wheel colliders ignore standard [PhysicsMaterial](/engine/6000.7/script-reference/unityengine/physicsmaterial.md) settings.

The way to simulate different ground materials is to query [WheelCollider](/engine/6000.7/script-reference/unityengine/wheelcollider.md) for its collision information (see [WheelCollider.GetGroundHit](/engine/6000.7/script-reference/unityengine/wheelcollider/getgroundhit.md)). Usually, you get the other collider the wheel is hitting, and modify the wheel's [\_forwardFriction](/engine/6000.7/script-reference/unityengine/wheelcollider/forwardfriction.md) and [\_sidewaysFriction](/engine/6000.7/script-reference/unityengine/wheelcollider/sidewaysfriction.md) based on the physics material of the ground.

The other members of the WheelHit structure are usually queried for information purposes or special effects. For example, a "slipping tire" sound can be played if [\_forwardSlip](/engine/6000.7/script-reference/unityengine/wheelhit/forwardslip.md) or [\_sidewaysSlip](/engine/6000.7/script-reference/unityengine/wheelhit/sidewaysslip.md) exceed some threshold.

Additional Resources: [WheelCollider.GetGroundHit](/engine/6000.7/script-reference/unityengine/wheelcollider/getgroundhit.md)

## Properties

| Property                                                                             | Description                                                                                         |
| ------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------- |
| [collider](/engine/6000.7/script-reference/unityengine/wheelhit/collider.md)         | The other [Collider](/engine/6000.7/script-reference/unityengine/collider.md) the wheel is hitting. |
| [force](/engine/6000.7/script-reference/unityengine/wheelhit/force.md)               | The magnitude of the force being applied for the contact.                                           |
| [forwardDir](/engine/6000.7/script-reference/unityengine/wheelhit/forwarddir.md)     | The direction the wheel is pointing in.                                                             |
| [forwardSlip](/engine/6000.7/script-reference/unityengine/wheelhit/forwardslip.md)   | Tire slip in the rolling direction. Acceleration slip is negative, braking slip is positive.        |
| [normal](/engine/6000.7/script-reference/unityengine/wheelhit/normal.md)             | The normal at the point of contact.                                                                 |
| [point](/engine/6000.7/script-reference/unityengine/wheelhit/point.md)               | The point of contact between the wheel and the ground.                                              |
| [sidewaysDir](/engine/6000.7/script-reference/unityengine/wheelhit/sidewaysdir.md)   | The sideways direction of the wheel.                                                                |
| [sidewaysSlip](/engine/6000.7/script-reference/unityengine/wheelhit/sidewaysslip.md) | Tire slip in the sideways direction.                                                                |