Car wheels spinning and/or rotating?

Hello,

How do I make car wheels spin and slow down when the car is stopped? And, How do I make the front wheels turn when pressing the left/right arrows? Help is very much appreciated.

Thanks

 

How are you controlling the car? Are you using the built-in physics engine, or are you moving it manually via the transform component?

 

i am using this script:

Code (csharp):

1. var CurrentSpeed : float = 0;
2. var RotationSpeed : float = 5.0;
3.  
4. function Update () {
5.  
6. transform.Translate(Vector3.forward * Time.deltaTime * CurrentSpeed , Space.Self);
7.  
8. if(CurrentSpeed < 0) {
9. CurrentSpeed += 0.25 * Time.deltaTime;
10. } else {
11. CurrentSpeed -= 0.25 * Time.deltaTime;
12. }
13.  
14. if(Input.GetKey(KeyCode.UpArrow)){
15. CurrentSpeed += Time.deltaTime;
16. }
17.  
18. if(Input.GetKey(KeyCode.DownArrow)){
19. CurrentSpeed -= Time.deltaTime;
20. }
21.  
22. if(Input.GetKey(KeyCode.LeftArrow)){
23. transform.Rotate(Vector3.up * Time.deltaTime * -RotationSpeed, Space.Self);
24. }
25.  
26. if(Input.GetKey(KeyCode.RightArrow)){
27. transform.Rotate(Vector3.up * Time.deltaTime * RotationSpeed, Space.Self);
28. }
29.  
30. }

Thanks for any help.

 

You can figure out approximately how much the wheels need to rotate (setting aside differentials and stuff like that) based on the current speed and the wheel radius.

This is off the top of my head so no guarantee of correctness, but it should look something like this (pseudocode - ish):

Code (csharp):

1. float distanceTraveled = speed * Time.deltaTime;
2. float rotationInRadians = distanceTraveled / wheelRadius;
3. float rotationInDegrees = rotationInRadians * Mathf.Rad2Deg;
4. wheel.transform.Rotate(rotationInDegrees, 0, 0);
5. // Or whatever axis is appropriate.

For making the front wheels turn, you'll want to make them child objects and then modify their local rotations appropriately.

 

Use my script: If you what to have fun

Code (csharp):

1. var FRwheel : WheelCollider; //wheel front left collider
2. var FLwheel : WheelCollider; //wheel front right collider
3. var MaxmotorTorque = 200.0; //Max car engine speed
4. var volate = 25;
5. var MaxBrakeTorque = 500.0;
6. private var Imbraking : boolean = false;
7. var WheelsFL : Transform; // front left wheel mesh only ( no collider)
8. var WheelsFR : Transform; // front right wheel mesh only ( no collider)
9. var WheelsBL : Transform; // back left wheel mesh only ( no collider)
10. var WheelsBR : Transform; // back right wheel mesh only ( no collider)
11. //fix wheels problem dependins the axis.
12. var fixX : float;
13. var fixY : float;
14. var fixZ : float;
15. // Gui Text Speed of the car volues.
16. var GuiSpeed : GUIText;
17. //Max speed and Current Speed.
18. var maxSpeed : float = 200.0;
19. var maxBackSpeed : float = 40.0;
20. var gearSpeed : int [];
21. private var CurrentSpeed = 0.0;
22. private var currentGear : int = 0;
23. function Start()
24. {
25.    rigidbody.centerOfMass.y = 0;
26. }
27. function FixedUpdate ()
28. {  
29.    SteelWheels ();
30.    GearSound();
31.    GearDrive();
32.  
33.    FRwheel.steerAngle = volate  * Input.GetAxis("Horizontal");
34.    FLwheel.steerAngle = volate  * Input.GetAxis("Horizontal");
35.  
36.    WheelsFL.Rotate(FLwheel.rpm / 60 * 360 * Time.deltaTime,0,0);
37.    WheelsFR.Rotate(FLwheel.rpm / 60 * 360 * Time.deltaTime,0,0);
38.    WheelsBL.Rotate(FLwheel.rpm / 60 * 360 * Time.deltaTime,0,0);
39.    WheelsBR.Rotate(FLwheel.rpm / 60 * 360 * Time.deltaTime,0,0);
40.  
41.  
42.    CurrentSpeed = (Mathf.PI * 2 * FLwheel.radius) * FLwheel.rpm * 60 / 1000;
43.    CurrentSpeed = Mathf.Round(CurrentSpeed);
44.  
45.    if ((CurrentSpeed > 0)  (Input.GetAxis("Vertical") <0))
46.    {
47.         Imbraking = true;
48.    }
49.    else
50.    {
51.   Imbraking = false;
52.   FLwheel.brakeTorque = 0;
53.   FRwheel.brakeTorque = 0;
54.    }  
55.  
56.    if ((CurrentSpeed < maxSpeed)  (CurrentSpeed > (maxBackSpeed * -1)))
57.    {
58.         FRwheel.motorTorque = MaxmotorTorque * Input.GetAxis("Vertical");
59.         FLwheel.motorTorque = MaxmotorTorque * Input.GetAxis("Vertical");  
60.    }
61.    else
62.    {
63.         FLwheel.motorTorque = 0;
64.   FRwheel.motorTorque = 0;
65.    }
66.    if (Imbraking == true)
67.    {
68.         FLwheel.brakeTorque = MaxBrakeTorque;
69.         FRwheel.brakeTorque = MaxBrakeTorque;
70.    }  
71.    GuiSpeed.text = CurrentSpeed.ToString();
72.  
73. }
74. function SteelWheels ()
75. {
76.   WheelsFL.localEulerAngles.y = FLwheel.steerAngle - WheelsFL.localEulerAngles.z;
77.   WheelsFR.localEulerAngles.y = FRwheel.steerAngle - WheelsFR.localEulerAngles.z;
78.  
79.   //Wheels fix.Fix the front wheels spin sides.
80.   fixX = WheelsFL.localEulerAngles.x;
81.   fixY = WheelsFL.localEulerAngles.y;
82.   fixZ = WheelsFL.localEulerAngles.z;  
83.  
84. }
85. function GearSound()
86. {
87.     var tempoMinSpeed : float = 0.00;
88.  var tempoMaxSpeed : float = 0.00;
89.  var currentPitch : float = 0.00;
90.  
91.  switch (currentGear)
92.  {
93.         case 0:
94.             tempoMinSpeed = 0.00;
95.             tempoMaxSpeed = gearSpeed[currentGear];
96.             break;
97.  
98.         default:
99.             tempoMinSpeed = gearSpeed[currentGear -1];  
100.          tempoMaxSpeed = gearSpeed[currentGear];
101.  }
102.  currentPitch = ((Mathf.Abs(CurrentSpeed) - tempoMinSpeed)/(tempoMaxSpeed - tempoMinSpeed)) +0.8;
103.     audio.pitch = currentPitch;
104. }
105. function GearDrive()
106. {
107.     var gearNumber : int;
108.  gearNumber = gearSpeed.length;
109.  
110.  for (var i=0; i< gearNumber; i++)
111.  {
112.      if(gearSpeed[i] > CurrentSpeed)
113.   {  
114.      currentGear = i;
115.      break;  
116.   }
117.  }
118. }

 

It's alright. I am using the car script from the tutorial, since mine already sucks.

 

Can you give a link to the tutorial (if you have any more questions we at least know where you are getting your information at)

And... Isn't that what tutorials are for?

 

The tutorial is the one in the unity resources page.

 

the script i post here is from german tutorials I do some modification upgrade.

 

Hi guys,

I'm trying to make a wheel (yes only one wheel without the car and everything else) and make it move using the Iphone accelerometer... it's getting quite complicate to achive.

I'm using an empty game object for the collider and a cylinder for the wheel... both are child of a parent gameObject with Rigidbody.

Is the cylinder the right way to make the wheel ?

 

Your cylinder have the wheelCollider?
If No, make sure you create an empty object and add the WheelCollider, and rescale the WhellCollider size whit your cylinder.
Is not recomender add directely wheelCollider to an cylinder wheels or mesh wheels.
Check the wheelCollider reference.

 

This all depends on how you are accomplishing keeping the vehicle upright. With 1 wheel the first assumption is that it will fall over. Honestly, in your case I would use a wheel collider and use code to keep the vehicle upright instead of physics.

And for what you are asking, write up some code and start a new thread. I believe that it warrants its own thread.

 

hi..i follow the script that you guys give but it doest work for me...

 

Assets/Scripts/Car Control.js(56,22): BCE0077: It is not possible to invoke an expression of type 'boolean'.

 

For C# ?

 

Thank You, I was searching for one without a wheel colliders.