Wheel Collider专门用于模拟车具轮胎的物理属性，内置了碰撞检测、轮胎摩擦模型等，可以用于实现车具的控制。
核心的几个变量：
motorTorque：驱动力，将其设为正值向前移动，负值向后移动
brakeTorque：制动力，该值为正
rpm：车轮转速，注意它是每分钟转动多少圈
steerAngle：转向角度，可以实现车具的转弯
mass：车轮的重量，单位kg
radius：车轮的半径
forwardFriction：车轮在正向转动时的摩擦力
sidewaysFriction：车轮在侧向转动时的摩擦力
了解了这几个核心变量后，下面简单实现车具的控制：
1.首先给车具模型添加刚体组件，假设重量为2吨，将Mass设为2000：
2.为每个车轮模型添加一个空父级，添加Wheel Collider组件，假设每个轮胎的重量为20kg：
3.注意Wheel Collider碰撞器不能被车身的碰撞器包裹，否则车子不会移动。另外注意如果没有给车身添加Rigybody组件的话，Scene窗口也是看不到Wheel Collider的。
4.为Wheel Collider添加motorTorque驱动力，声明一个float类型的变量，暂定为200f， 假设车辆为后驱，给两个后轮添加驱动力：
代码语言：javascript复制[SerializeField] private float motorTorque = 200f;代码语言：javascript复制float verticalInput = Input.GetAxisRaw("Vertical");
//驱动
rlWheelCollider.motorTorque = verticalInput * motorTorque;
rrWheelCollider.motorTorque = verticalInput * motorTorque;5.车辆移动时，使车轮模型滚动，滚动的角度通过Wheel Collider组件的rpm属性获取，上面提到该属性代表车轮每分钟转动多少圈，因此我们将其除以60，代表每秒钟转动的圈数，1圈为360度，因此再乘以360即可获得要滚动的角度：
代码语言：javascript复制//车轮模型滚动
flWheelTransform.Rotate(flWheelCollider.rpm / 60 * 360 * Time.deltaTime * Vector3.right);
frWheelTransform.Rotate(frWheelCollider.rpm / 60 * 360 * Time.deltaTime * Vector3.right);
rlWheelTransform.Rotate(rlWheelCollider.rpm / 60 * 360 * Time.deltaTime * Vector3.right);
rrWheelTransform.Rotate(rrWheelCollider.rpm / 60 * 360 * Time.deltaTime * Vector3.right);6.为Wheel Collider添加转向，声明一个float类型变量来限制车轮最大的转动角度：
代码语言：javascript复制[SerializeField] private float maxSteerAngle = 45f;代码语言：javascript复制float horizontalInput = Input.GetAxisRaw("Horizontal");
//转向
flWheelCollider.steerAngle = horizontalInput * maxSteerAngle;
frWheelCollider.steerAngle = horizontalInput * maxSteerAngle;steerAngle仅仅是Wheel Collider的转向角度，还需要调整车轮实际模型的转向角度：
代码语言：javascript复制//车轮模型转向
flWheelCollider.transform.localEulerAngles = new Vector3(0f, flWheelCollider.steerAngle, 0f);
frWheelCollider.transform.localEulerAngles = new Vector3(0f, frWheelCollider.steerAngle, 0f);7.通过brakeTorque属性实现刹车制动功能，假设按下Space空格键时进行刹车：
代码语言：javascript复制//刹车
bool isBraking = Input.GetKey(KeyCode.Space);
rlWheelCollider.brakeTorque = isBraking ? brakeTorque : 0f;
rrWheelCollider.brakeTorque = isBraking ? brakeTorque : 0f;8.还要注意Rigybody组件的centerOfMass位置需要设为车身的底部：
最终代码：
代码语言：javascript复制using UnityEngine;
public class VehicleController : MonoBehaviour
{
[SerializeField] private WheelCollider flWheelCollider;
[SerializeField] private WheelCollider frWheelCollider;
[SerializeField] private WheelCollider rlWheelCollider;
[SerializeField] private WheelCollider rrWheelCollider;
[SerializeField] private Transform flWheelTransform;
[SerializeField] private Transform frWheelTransform;
[SerializeField] private Transform rlWheelTransform;
[SerializeField] private Transform rrWheelTransform;
[SerializeField] private Transform centerOfMass;
[SerializeField] private float motorTorque = 200f;
[SerializeField] private float brakeTorque = 200f;
[SerializeField] private float maxSteerAngle = 45f;
private void Start()
{
GetComponent
}
private void Update()
{
float verticalInput = Input.GetAxisRaw("Vertical");
float horizontalInput = Input.GetAxisRaw("Horizontal");
//驱动
rlWheelCollider.motorTorque = verticalInput * motorTorque;
rrWheelCollider.motorTorque = verticalInput * motorTorque;
//转向
flWheelCollider.steerAngle = horizontalInput * maxSteerAngle;
frWheelCollider.steerAngle = horizontalInput * maxSteerAngle;
//车轮模型转动
flWheelTransform.Rotate(flWheelCollider.rpm * 360 * Time.deltaTime * Vector3.right);
frWheelTransform.Rotate(frWheelCollider.rpm * 360 * Time.deltaTime * Vector3.right);
rlWheelTransform.Rotate(rlWheelCollider.rpm * 360 * Time.deltaTime * Vector3.right);
rrWheelTransform.Rotate(rrWheelCollider.rpm * 360 * Time.deltaTime * Vector3.right);
//车轮模型转向
flWheelCollider.transform.localEulerAngles = new Vector3(0f, flWheelCollider.steerAngle, 0f);
frWheelCollider.transform.localEulerAngles = new Vector3(0f, frWheelCollider.steerAngle, 0f);
//刹车
bool isBraking = Input.GetKey(KeyCode.Space);
rlWheelCollider.brakeTorque = isBraking ? brakeTorque : 0f;
rrWheelCollider.brakeTorque = isBraking ? brakeTorque : 0f;
}
}