Object rotation for a motorcycle stunts game

Question

I'm trying to create a rotation for my bikes but I'm struggling with the quaternion construction.

What I need:

The bike rotates on its local x axis (back flips, front flips, wheelies).
The bike steers on its local y axis.
Rolling is not permitted so no rotation on the z axis.
Must be a single object, no hierarchy.

I tried creating my quaternion as such:

 Quaternion desiredRotation = Quaternion.Euler(flipsRotation, steeringRotation, 0);

The problem is that as I do flips and I'm at 90 degrees on the x axis the bike tries to flip on the z axis.

I tried some work around like this:

 float adjustedRoll = 0;
 float adjustedYaw = steeringRotation;
 
 //adjust angles if bike is flipped
 if(transform.up.y < 0)
 {
      adjustedRoll = 180;
      adjustedYaw = 180 + steeringRotation;
 }
 
 Quaternion desiredRotation = Quaternion.Euler(flipsRotation, adjustedYaw, adjustedRoll);

This sort of works but I still get some glitches. I'm sure there is a more elegant solution to this problem.

Any ideas?

Answer 1

Answer by Supershandy · Jul 25, 2014 at 02:37 PM

You can just lock off the angles by setting the rotation variable to zero.

E.g

 Var bike : Transform;
 
 Function Update ()
 
 {
     If (bike.up.y < 0)
     {
         AdjustedRoll = 180;
         AdjustedYaw = 180 + steeringRotation;
         bike.rotation.z = 0;
     }
 }

I can't guarantee anything though as I'm currently at work and can't test it.

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Answer 2

Answer by ratamorph · Jul 26, 2014 at 08:00 PM

I fixed my issue! Here's how I calculated the final rotation:

 Vector3 pitchYawRoll = UtilityFunctions.GetPitchYawRollDeg(transform.rotation);
 
 Quaternion pitchRotation = Quaternion.AngleAxis(pitchYawRoll.x, Vector3.right);
 Quaternion yawRotation = Quaternion.LookRotation(steeringDirection, Vector3.up);
 
 Quaternion desiredRotation = yawRotation * pitchRotation;

The code for GetPitchYawRollDeg(Quaternion transform) is in my other question http://answers.unity3d.com/questions/756467/getting-object-rotation-on-just-1-axis.html

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Answer 3

Answer by bhongleram · Jan 25, 2020 at 08:16 PM

Lock the z rotation constraint from inspector.

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Answer 4

i need help with something , i am trying to check if the player's rotation is bigger or smaller than a number if it is i will end the game but if i start it it ends immediately
public class PlayerMovement : MonoBehaviour { public float sideWaysForce = 0.5f;

 protected JoyButton joybutton;

 protected JoyButtonRight joybuttonright;

 public Rigidbody rb;

 public float forward = 2100f;

public float sideWaysForceKEYBOARD = 0.7f;

 public AudioSource backgroundMusic;

protected Brake brake;

 protected Gas gas;

 private float increaseVolume = 0.005f;

 private float increasePitch = 0.0005f;

 public float maxSpeed = 1600f;

 public float minspeed = 0f;

 public float minspeedmultiplier = 1.45f;

 public Transform playert; 

 public float delay = 13f;


 public void Start()
 {
     backgroundMusic.Play();
     joybutton = FindObjectOfType<JoyButton>();
     joybuttonright = FindObjectOfType<JoyButtonRight>();
     gas = FindObjectOfType<Gas>();
     brake = FindObjectOfType<Brake>();
   
     
 }
 private void Update()
 {

    
     backgroundMusic.volume += increaseVolume;
     backgroundMusic.pitch += increasePitch;
     if (backgroundMusic.pitch > 1)
     {
         backgroundMusic.pitch = 1f;

     }
     if (transform.rotation.eulerAngles.x> 60) 
     {
         GameObject.Find("GameManager").SendMessage("Restart");

     }
     if (transform.rotation.eulerAngles.x > -60)
     {
         GameObject.Find("GameManager").SendMessage("Restart");

     }
 }
 void FixedUpdate()
 {


     if (brake.brakeispressed)
     {
         forward -= 70;
     }

     if (gas.Gasispressed)
     {
         forward += 70;
     }

     if (forward <= 400)
     {
         forward = forward + 70;

     }
     if (joybutton.Pressed)
     {

         rb.AddForce(-sideWaysForce , 0, 0, ForceMode.VelocityChange);
     }
     if (joybuttonright.PressedRight)
     {
         rb.AddForce(sideWaysForce , 0, 0, ForceMode.VelocityChange);

     }
     


     if (forward > maxSpeed)
     {
         forward = forward = maxSpeed; 

     }

     rb.AddForce(0, 0,forward * Time.fixedDeltaTime );

     if (Input.GetKey("a"))
     {
         rb.AddForce(-sideWaysForceKEYBOARD, 0, 0, ForceMode.VelocityChange);



     }
     if (Input.GetKey("s"))
     {
         forward = forward - 70;

     }
     if (Input.GetKey("w"))
     {
         forward = forward + 70;

     }
     if (Input.GetKey("d"))
     {
         rb.AddForce(sideWaysForceKEYBOARD, 0, 0, ForceMode.VelocityChange);

     }




     if (rb.position.y < -1f)
     {
         restartTimerAndScore();
         backgroundMusic.Stop();


     }
     if (rb.position.y > 3f)
     {
        
         restartTimerAndScore();
         backgroundMusic.Stop();
     }
     if (forward < minspeed)
     {
         forward = forward = minspeed * minspeed;
     }
    

 }
  

 public void restartTimerAndScore()
 {
     GameObject.Find("Player").SendMessage("restartTimer");
     GameObject.Find("SC").SendMessage("restartscore");
     FindObjectOfType<GameManager>().EndGame();
     

 }

}

Object rotation for a motorcycle stunts game

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