Rotate Object from Other Local Object

Questions & Answers
1

is there a way to rotate an object, on the current local axis of an other object?

something (this is not right) like this: transform.Rotate(-5,0,0,Space.GameObject.Find(“OtherObject”));

2

Do you mean Transform.localRotation ?
The rotation of the transform relative to the parent transform’s rotation.
If so ,just change its value.

3

Rotations are always tricky. If both objects have the same rotation at Start and have no parents, you can copy transform.rotation from one object to the other - the second object will follow any rotation applied to the first one. If they are childed to other objects, however, you may have lots of weird effects.

EDITED: There is a function to rotate an object around any arbitrary axis, RotateAround. You can set this axis to some local vector of another object: use .up vector for Y, .right for X or .forward for Z.
It’s not possible to rotate around more than one axis in a single RotateAround.
The example below rotate around the Y axis of the object defined in master:

var master: Transform; // reference object

function Update(){

	var ang = Input.GetAxis("Horizontal") * 30 * Time.deltaTime;
	transform.RotateAround(transform.position, master.up, ang);
}