localEulerAngles.x rotates as in world space

Question

Hi! I'm making a game with flying pigeon on android with accelerometer contol, and i have a trouble with rotating it in local space. Everything is allright when i'm flying straight and want to turn up or down (around X axis in local space).

When i want to turn left or right, firstly i need to lean to one side (rotate around z axis - blue arrow), and then to rotate around X axis in local space (red arrow).

alt text

But when i rotate around X axis in local space, it turns up, just as in world space! (red arrow, wanted rotation - green arrow)

alt text

Here is code i use to rotate it:

 transform.localEulerAngles = new Vector3 (-Input.acceleration.z * rotationAngle,    
                                    transform.localEulerAngles.y,
                                   -Input.acceleration.x * rotationAngle);

It gives the same result as using transform.eulerAngles and transform.localRotation gives the same result as transform.rotation

transform.Rotate with local space works properly, but it's not suitable for accelerometer control. What's the problem?

Answer 1

Answer by Bunny83 · Jul 17, 2014 at 12:24 PM

Well, is your object actually a child of another object? If not ALL local properties are "local to the world" and do exactly the same as the world space properties. The Rotate method applies a relative rotation to your object. localEuerAngles (or localRotation) is an absolute rotation relative to the parent. Also euler angles have a fix order in which the rotations happens.

In Unity it's: z, x, y. You also shouldn't use eulerAngles for such a control as euler angles suffer from gimbal lock. It's better to directly use Quaternions. I would probably use a combination of LookRotation and AngleAxis to specify the initial rotation and a rotation based on the gravity vector.

Add comment · Show 1 · Share

AzovUa · Jul 18, 2014 at 01:03 AM 0

Share

Sorry, maybe i'm idiot, but i can't understand anything... I tried using Quaternions, but it also rotates in world space...

 float tiltAroundZ = acceleration.z * rotationAngle;
 float tiltAroundX = acceleration.x * rotationAngle;
 Quaternion rotX = Quaternion.AngleAxis (tiltAroundX, Vector3.right);
 Quaternion rotZ = Quaternion.AngleAxis (tiltAroundZ, Vector3.back);
 Quaternion lookRot = Quaternion.LookRotation (Vector3.forward, Vector3.up);
 Quaternion rot = rotX * rotZ * lookRot;
 transform.rotation = Quaternion.Slerp(transform.rotation, rot, Time.deltaTime * smooth);

localEulerAngles.x rotates as in world space

1 Reply

Your answer

Follow this Question

Related Questions