WheelCollider
A special collider for vehicle wheels.
Read time 9 minutesLast updated 4 days ago
Definition
- Type: Class
- Namespace: UnityEngine
- Assembly: UnityEngine.VehiclesModule
- Inherits from: Collider
public class WheelCollider : Collider
Remarks
Wheel collider is used to model vehicle wheels. It simulates a spring and damper suspension setup, and uses a slip based tire friction model to calculate wheel contact forces.
Wheel's collision detection is performed by casting a ray from WheelCollider.center downwards the local y-axis. The wheel has a WheelCollider.radius and can extend downwards by WheelCollider.suspensionDistance amount.
The wheel is controlled with WheelCollider.motorTorque, WheelCollider.brakeTorque and WheelCollider.steerAngle properties.
Wheel collider computes friction separately from the rest of physics engine, using a slip based friction model. This allows for more realistic behaviour, but makes wheel colliders ignore standard PhysicsMaterial settings. Simulation of different road materials is done by changing the WheelCollider.forwardFriction and WheelCollider.sidewaysFriction based on what material the wheel is hitting. Additional Resources: WheelCollider.GetGroundHit and WheelFrictionCurve.
Properties
Property | Description |
|---|---|
| brakeTorque | Brake torque expressed in Newton metres. |
| center | The center of the wheel, measured in the object's local space. |
| forceAppPointDistance | Application point of the suspension and tire forces measured from the base of the resting wheel. |
| forwardFriction | Properties of tire friction in the direction the wheel is pointing in. |
| isGrounded | Indicates whether the wheel currently collides with something (Read Only). |
| mass | The mass of the wheel, expressed in kilograms. Must be larger than zero. Typical values would be in range (20,80). |
| motorTorque | Motor torque on the wheel axle expressed in Newton metres. Positive or negative depending on direction. |
| radius | The radius of the wheel, measured in local space. |
| rotationSpeed | Rotation speed of the wheel, measured in degrees per second. |
| rpm | Current wheel axle rotation speed, in rotations per minute (Read Only). |
| sidewaysFriction | Properties of tire friction in the sideways direction. |
| sprungMass | The mass supported by this WheelCollider. |
| steerAngle | Steering angle in degrees, always around the local y-axis. |
| suspensionDistance | Maximum extension distance of wheel suspension, measured in local space. |
| suspensionExpansionLimited | Limits the expansion velocity of the Wheel Collider's suspension. If you set this property on a Rigidbody that has several Wheel Colliders, such as a vehicle, then it affects all other Wheel Colliders on the Rigidbody. |
| suspensionSpring | The parameters of wheel's suspension. The suspension attempts to reach a target position by applying a linear force and a damping force. |
| wheelDampingRate | The damping rate of the wheel. Must be larger than zero. |
Methods
Method | Description |
|---|---|
| ConfigureVehicleSubsteps | Configure vehicle sub-stepping parameters. |
| GetGroundHit | Gets ground collision data for the wheel. |
| GetWorldPose | Gets the world space pose of the wheel accounting for ground contact, suspension limits, steer angle, and rotation angle (angles in degrees). |
| ResetSprungMasses | Reset the sprung masses of the vehicle. |
Inheritance
Operators
Operator | Description |
|---|---|
| operator == | Compares two object references to see if they refer to the same object. |
| bool | Determines whether the object exists. |
| operator != | Compares if two objects refer to a different object. |