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Move a Softbody Car

A Car Softbody is formed of 2 Softbodies that act as the wheels, and a Softbody for the car frame that connects the two with 2 Pin Joints with Motor. This tutorial is also available in the GitHub repo as a sample samples/softbody2d/car-demo.

Create two new SoftBody2D wheel nodes​

Similar as previous tutorial, create two Softbody and add the texture samples/softbody2d/Boiled_Egg_Half.png to them. Move them a bit apart. You should see in the 2D scene view the following:

scene view

Name them Wheel 1 and Wheel 2.

Create a World Boundary​

Create a RigidBody2D and add as child a CollisionShape2D with Shape set to WorldBoundaryShape2D and move it below the Softbodies.

Create a SoftBody2D frame node​

Create a Softbody and add the texture samples/softbody2d/softbody2d_banner.jpg to them. Rename it to Frame. Scale it to 0.4 for both X and Y at the Transform property. Move it a bit on top of the two wheels. You should see in the 2D scene view the following:

rectangle

Create the PinJoint2D nodes​

Create two PinJoint2D nodes placed on the center of the wheels.

You should now have the following car:

car

Now connect the pinjoints Node B to the Rigidbody closest on the Frame Softbody, and the Node A to the corresponding Rigidbody from each Wheel Softbody. Eg. for me the following were set:

  • Node A for first pinjoint: ../../Wheel 1/Bone-15

  • Node B for first pinjoint: ../Frame/Bone4

  • Node A for second pinjoint: ../../Wheel 2/Bone-15

  • Node B for first pinjoint: ../Frame/Bone44

Next, go to the Frame Softbody and set it's z_index to -1 so it's behind the wheels:

behind

Next, add the following Script on the root node:

extends Node2D

@onready var pin1 : PinJoint2D = $PinJoint2D
@onready var pin2 : PinJoint2D = $PinJoint2D2

const SPEED = 6000

# Called every frame. 'delta' is the elapsed time since the previous frame.
func _physics_process(delta: float) -> void:
	var direction := Input.get_axis("ui_left", "ui_right")
	if direction:
		pin1.motor_enabled = true
		pin2.motor_enabled = true
		pin1.motor_target_velocity = direction * SPEED
		pin2.motor_target_velocity = direction * SPEED
	else:
		pin1.motor_enabled = false
		pin2.motor_enabled = false

Try it out​

Click the Run Current Scene button. If you did everything right, you will see the following:

gif