ptamzz ptamzz - 4 months ago 122
C# Question

how to make a gameObject rotate around another gameObject in Unity in the rotating plane

I've two gameObjects,

sphereOne
and
sphereTwo
as the children of an empty gameObject
both
.

I've this C# code attached to a
sphereTwo


void Update ()
{
transform.RotateAround(sphereOne.transform.position, new Vector3(0, 1, 0), 100*Time.deltaTime);
}


This lets
sphereTwo
rotate around
sphereOne
.

When I rotate the parent gameObject
both
, it rotates only on that specific plane.

enter image description here

How do I dynamically update the transform position of the rotating sphere so that it lies on the same plane as the parent Object's rotation?

Answer

The second parameter in Transform.RotateAround() is the axis which determines the orientation of the plane on which sphereTwo rotates around sphereOne. Right now, you have this set to a static value of new Vector3(0, 1, 0), basically the world's up vector.

To have the axis instead be based on the orientation of sphereOne, use its Transform.up vector instead - this will change based on the world-space rotation of sphereOne's transform:

void Update () 
{
    transform.RotateAround(sphereOne.transform.position, sphereOne.transform.up, 100*Time.deltaTime);
}

(You could probably alternatively use both.transform.up, depending on the situation.)

Hope this helps! Let me know if you have any questions.

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