How to rotate a game object pivoting by the center, and not by the corner?

Unity Engine
1

Note that I’m using Unity UI to help visualize what I’m doing.

This is how the arrow rotates when just applying a new Quaternion value to its local rotation:

And this is what I plan to understand Quaternion rotations by adding an offset, in order to get this result (not yet happening at the moment):

This is my pseudo-code that doesn’t seem to work like I expected:

Transform transform = GetComponent<Transform>();
transform.position += new Vector3(arrow.GetWidth() / 2f, arrow.GetHeight() / 2f, 0f);
transform.localRotation = Quaternion.Euler(0f, 0f, angle) * Vector3.one;
transform.position -= new Vector3(arrow.GetWidth() / 2f, arrow.GetHeight() / 2f, 0f);

How do you rotate a game object by offsetting its pivot point (non Unity UI wise), like the green arrow in the second GIF?

2

You could use RotateAround

transform.rotation = Quaternion.identity;
transform.RotateAround(transform.position + new Vector3(arrow.GetWidth() / 2f, arrow.GetHeight() / 2f, 0f), Vector3.forward, angle);

]

3

You have three options.

  1. RotateAround
  2. Fix the pivot of your mesh in 3d tool
  3. Make mesh a child of gameobject and rotate parent.
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4

Thank you.

Where can I look up Quaternion math involving rotating game objects? It’s okay if there’s no answer.

5

Third solution is so simple and makes the job done! Thanks!

1 Like
6

https://eater.net/quaternions

1 Like