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Hey everyone, i've stumbled upon a pretty weird issue when rotating a sphere.

Even though the sphere has absolutely neither parents nor children, it seems to be rotating around something...

here's the rotation code :

transform.Rotate(touchDeltaPosition.y * speeed,-touchDeltaPosition.x * speeed, 0,Space.World);

Also, i've already tried to attach a rigidbody and freeze x,y and z positions, no success

Answer 1

0

Have you tried using space.self, instead of space.world?

though im not sure it would help.

If that doesnt work you can try the following; spawn a new gameobject, then move said gameobject to the center of your sphere, set the sphere as a child of the gameobject, then apply the rotation to the gameobject instead.

If that doesnt work, then im out of ideas.

just out of curiosity, where is the pivot of the sphere located?

answered Jun 30 '11 at 08:03 AM

Kacer
705 ● 15 ● 18 ● 31

if you mean the XYZ rotation bows with pivot, they are in the sphere's middle, i've already tried to change the space line, that didnt help either...

how do i get a gameobject exactly to my sphere's center?

Jun 30 '11 at 08:34 AM biohazard

set the gameobject as a child of the sphere, then move the gameobject to 0,0,0.

Or you can move both objects to world origin.

Jun 30 '11 at 08:43 AM Kacer

this didn't work, for some weird reason the sphere (its not a generated one from unity) has it's center way too low which causes this issue...

is there a way to recalculate the center of a gameobject?

Jun 30 '11 at 09:29 AM biohazard

Ohhh, now it makes more snese, what program did you use to make the sphere? (you could have told me to begin with, that you werent using the sphere from unity :P)

you just need to realign the pivot in your chosen 3D application, just move the pivot to the center of the sphere and it should be fixed.

Jun 30 '11 at 09:36 AM Kacer

@Kacer any way to do it only with scripts, without going to the "3D application"? There should be some way.

Jun 04 '12 at 09:12 PM Cawas

(comments are locked)

Answer 2

Wolfram did offer a nice solution, mostly already given elsewhere: use renderer.bounds.center along with RotateAround:

transform.RotateAround(renderer.bounds.center, new Vector3(1, -1, 0), speeed); //  <-- why 3 e's speed?

The only problem in this solution is that we can't set the rotation to a specific value.

Here's another Wolfram's idea that will use the same renderer.bounds.center but with a parenting GameObject instead:

    GameObject myContainer = new GameObject();
    myContainer.name = "rot_" + transform.gameObject.name;
    myContainer.transform.position = renderer.bounds.center;
    myContainer.transform.parent = transform.parent;
    transform.parent = myContainer.transform;

    // now rotate myContainer at your will
    myContainer.transform.Rotate(touchDeltaPosition.y * speeed,-touchDeltaPosition.x * speeed, 0,Space.World);

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pretty weird issue with rotating a sphere

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