Table of Contents

Class VehicleWheel3D

A 3D physics body for a VehicleBody3D that simulates the behavior of a wheel.

Inheritance
VehicleWheel3D

Remarks

A node used as a child of a VehicleBody3D parent to simulate the behavior of one of its wheels. This node also acts as a collider to detect if the wheel is touching a surface.

Note: This class has known issues and isn't designed to provide realistic 3D vehicle physics. If you want advanced vehicle physics, you may need to write your own physics integration using another PhysicsBody3D class.

See Also

3D Truck Town Demo

Properties

brake

Slows down the wheel by applying a braking force. The wheel is only slowed down if it is in contact with a surface. The force you need to apply to adequately slow down your vehicle depends on the mass of the vehicle. For a vehicle with a mass set to 1000, try a value in the 25 - 30 range for hard braking.

var brake : float = 0.0

Property Value

float

Remarks

damping_compression

The damping applied to the suspension spring when being compressed, meaning when the wheel is moving up relative to the vehicle. It is measured in Newton-seconds per millimeter (N⋅s/mm), or megagrams per second (Mg/s). This value should be between 0.0 (no damping) and 1.0, but may be more. A value of 0.0 means the car will keep bouncing as the spring keeps its energy. A good value for this is around 0.3 for a normal car, 0.5 for a race car.

var damping_compression : float = 0.83

Property Value

float

Remarks

  • void set_damping_compression(float value)
  • float get_damping_compression

damping_relaxation

The damping applied to the suspension spring when rebounding or extending, meaning when the wheel is moving down relative to the vehicle. It is measured in Newton-seconds per millimeter (N⋅s/mm), or megagrams per second (Mg/s). This value should be between 0.0 (no damping) and 1.0, but may be more. This value should always be slightly higher than the damping_compression property. For a damping_compression value of 0.3, try a relaxation value of 0.5.

var damping_relaxation : float = 0.88

Property Value

float

Remarks

  • void set_damping_relaxation(float value)
  • float get_damping_relaxation

engine_force

Accelerates the wheel by applying an engine force. The wheel is only sped up if it is in contact with a surface. The mass of the vehicle has an effect on the acceleration of the vehicle. For a vehicle with a mass set to 1000, try a value in the 25 - 50 range for acceleration.

Note: The simulation does not take the effect of gears into account, you will need to add logic for this if you wish to simulate gears.

A negative value will result in the wheel reversing.

var engine_force : float = 0.0

Property Value

float

Remarks

  • void set_engine_force(float value)
  • float get_engine_force

steering

The steering angle for the wheel, in radians. Setting this to a non-zero value will result in the vehicle turning when it's moving.

var steering : float = 0.0

Property Value

float

Remarks

  • void set_steering(float value)
  • float get_steering

suspension_max_force

The maximum force the spring can resist. This value should be higher than a quarter of the mass of the VehicleBody3D or the spring will not carry the weight of the vehicle. Good results are often obtained by a value that is about 3× to 4× this number.

var suspension_max_force : float = 6000.0

Property Value

float

Remarks

  • void set_suspension_max_force(float value)
  • float get_suspension_max_force

suspension_stiffness

The stiffness of the suspension, measured in Newtons per millimeter (N/mm), or megagrams per second squared (Mg/s²). Use a value lower than 50 for an off-road car, a value between 50 and 100 for a race car and try something around 200 for something like a Formula 1 car.

var suspension_stiffness : float = 5.88

Property Value

float

Remarks

  • void set_suspension_stiffness(float value)
  • float get_suspension_stiffness

suspension_travel

This is the distance the suspension can travel. As Godot units are equivalent to meters, keep this setting relatively low. Try a value between 0.1 and 0.3 depending on the type of car.

var suspension_travel : float = 0.2

Property Value

float

Remarks

  • void set_suspension_travel(float value)
  • float get_suspension_travel

use_as_steering

If true, this wheel will be turned when the car steers. This value is used in conjunction with steering and ignored if you are using the per-wheel steering value instead.

var use_as_steering : bool = false

Property Value

bool

Remarks

  • void set_use_as_steering(bool value)
  • bool is_used_as_steering

use_as_traction

If true, this wheel transfers engine force to the ground to propel the vehicle forward. This value is used in conjunction with engine_force and ignored if you are using the per-wheel engine_force value instead.

var use_as_traction : bool = false

Property Value

bool

Remarks

  • void set_use_as_traction(bool value)
  • bool is_used_as_traction

wheel_friction_slip

This determines how much grip this wheel has. It is combined with the friction setting of the surface the wheel is in contact with. 0.0 means no grip, 1.0 is normal grip. For a drift car setup, try setting the grip of the rear wheels slightly lower than the front wheels, or use a lower value to simulate tire wear.

It's best to set this to 1.0 when starting out.

var wheel_friction_slip : float = 10.5

Property Value

float

Remarks

  • void set_friction_slip(float value)
  • float get_friction_slip

wheel_radius

The radius of the wheel in meters.

var wheel_radius : float = 0.5

Property Value

float

Remarks

wheel_rest_length

This is the distance in meters the wheel is lowered from its origin point. Don't set this to 0.0 and move the wheel into position, instead move the origin point of your wheel (the gizmo in Godot) to the position the wheel will take when bottoming out, then use the rest length to move the wheel down to the position it should be in when the car is in rest.

var wheel_rest_length : float = 0.15

Property Value

float

Remarks

  • void set_suspension_rest_length(float value)
  • float get_suspension_rest_length

wheel_roll_influence

This value affects the roll of your vehicle. If set to 1.0 for all wheels, your vehicle will resist body roll, while a value of 0.0 will be prone to rolling over.

var wheel_roll_influence : float = 0.1

Property Value

float

Remarks

  • void set_roll_influence(float value)
  • float get_roll_influence

Methods

get_contact_body

Qualifiers: const

Returns the contacting body node if valid in the tree, as Node3D. At the moment, GridMap is not supported so the node will be always of type PhysicsBody3D.

Returns null if the wheel is not in contact with a surface, or the contact body is not a PhysicsBody3D.

Node3D get_contact_body

get_contact_normal

Qualifiers: const

Returns the normal of the suspension's collision in world space if the wheel is in contact. If the wheel isn't in contact with anything, returns a vector pointing directly along the suspension axis toward the vehicle in world space.

Vector3 get_contact_normal

get_contact_point

Qualifiers: const

Returns the point of the suspension's collision in world space if the wheel is in contact. If the wheel isn't in contact with anything, returns the maximum point of the wheel's ray cast in world space, which is defined by wheel_rest_length + wheel_radius.

Vector3 get_contact_point

get_rpm

Qualifiers: const

Returns the rotational speed of the wheel in revolutions per minute.

float get_rpm

get_skidinfo

Qualifiers: const

Returns a value between 0.0 and 1.0 that indicates whether this wheel is skidding. 0.0 is skidding (the wheel has lost grip, e.g. icy terrain), 1.0 means not skidding (the wheel has full grip, e.g. dry asphalt road).

float get_skidinfo

is_in_contact

Qualifiers: const

Returns true if this wheel is in contact with a surface.

bool is_in_contact