WheelCollider steering angle while sliding

AMM22 · March 14, 2020, 4:54am

I’m using the Unity Vehicles Tools for this. (Vehicle Tools | Tutorial Projects | Unity Asset Store)

I changed it slightly so the handbrake stops all four wheels rather than just the rear wheels.

When I hold down the handbrake so all the wheels stop moving, I’m still able to turn the car left and right with the steerAngle.

I don’t understand why the steerAngle is still directing the rigidbody when the tire has no traction.

Is there a way to prevent the WheelCollider from changing the direction of the rigidbody based on the steerAngle while the WheelCollider is completely sliding?

public class WheelDrive : MonoBehaviour
{
    [Tooltip("Maximum steering angle of the wheels")]
	public float maxAngle = 30f;
	[Tooltip("Maximum torque applied to the driving wheels")]
	public float maxTorque = 300f;
	[Tooltip("Maximum brake torque applied to the driving wheels")]
	public float brakeTorque = 30000f;
	[Tooltip("If you need the visual wheels to be attached automatically, drag the wheel shape here.")]
	public GameObject wheelShape;

	[Tooltip("The vehicle's speed when the physics engine can use different amount of sub-steps (in m/s).")]
	public float criticalSpeed = 5f;
	[Tooltip("Simulation sub-steps when the speed is above critical.")]
	public int stepsBelow = 5;
	[Tooltip("Simulation sub-steps when the speed is below critical.")]
	public int stepsAbove = 1;

	[Tooltip("The vehicle's drive type: rear-wheels drive, front-wheels drive or all-wheels drive.")]
	public DriveType driveType;

    private WheelCollider[] m_Wheels;

    // Find all the WheelColliders down in the hierarchy.
	void Start()
	{
		m_Wheels = GetComponentsInChildren<WheelCollider>();

		for (int i = 0; i < m_Wheels.Length; ++i) 
		{
			var wheel = m_Wheels *;*

 	// Create wheel shapes only when needed.*

```
 	if (wheelShape != null)*
```
```
 	{*
```
```
 		var ws = Instantiate (wheelShape);*
```

 		ws.transform.parent = wheel.transform;*

```
 	}*
```
```
 }*
```
}*
// This is a really simple approach to updating wheels.*
// We simulate a rear wheel drive car and assume that the car is perfectly symmetric at local zero.*
// This helps us to figure our which wheels are front ones and which are rear.*
void Update()*
{*

 m_Wheels[0].ConfigureVehicleSubsteps(criticalSpeed, stepsBelow, stepsAbove);*

_ float angle = maxAngle * Input.GetAxis(“Horizontal”);_
_ float torque = maxTorque * Input.GetAxis(“Vertical”);_

 float handBrake = Input.GetKey(KeyCode.X) ? brakeTorque : 0;*

 foreach (WheelCollider wheel in m_Wheels)*

```
 {*
```

 	// A simple car where front wheels steer while rear ones drive.*

 	if (wheel.transform.localPosition.z > 0)*

```
 		wheel.steerAngle = angle;*
```
```
 	wheel.brakeTorque = handBrake;*
```

 	if (wheel.transform.localPosition.z < 0 && driveType != DriveType.FrontWheelDrive)*

```
 	{*
```
```
 		wheel.motorTorque = torque;*
```
```
 	}*
```

 	if (wheel.transform.localPosition.z >= 0 && driveType != DriveType.RearWheelDrive)*

```
 	{*
```
```
 		wheel.motorTorque = torque;*
```
```
 	}*
```
```
 	// Update visual wheels if any.*
```
```
 	if (wheelShape)* 
```
```
 	{*
```
```
 		Quaternion q;*
```
```
 		Vector3 p;*
```
```
 		wheel.GetWorldPose (out p, out q);*
```

 		// Assume that the only child of the wheelcollider is the wheel shape.*

 		Transform shapeTransform = wheel.transform.GetChild (0);*

if (wheel.name == “a0l” || wheel.name == “a1l” || wheel.name == “a2l”)
{
shapeTransform.rotation = q * Quaternion.Euler(0, 180, 0);
shapeTransform.position = p;
}
else
{
shapeTransform.position = p;
shapeTransform.rotation = q;
}

```
 	}*
```
```
 }*
```
}*
}

Namey5 · March 14, 2020, 5:52am

WheelColliders use different configurable settings for both forward and sideways traction. If you want the traction to be uniform when using the handbrake, you can adjust the collider settings to have the same traction for both directions;

In theory, you could just change one of the friction curves to match the other, then reset after;

private WheelFrictionCurve sideFriction;

void Awake ()
{
    sideFriction = wheel.sidewaysFriction;
}

...

//Then, in update
if (handbrake > 0)
    wheel.sidewaysFriction = wheel.forwardFriction;
else
    wheel.sidewaysFriction = sideFriction;