Rotating an object around the same pivot gives different results - unity3d

Question

Rotating an object around the same pivot gives different results
So I'm trying to make a door that opens when clicked on, and I have a door that works good as is, but for some reason when I try to make it work for another door using RotateAround, it moves along the Z axis when closing. The code is identical to the other door that works and works when opening this door, so I have no clue as to why it's having trouble closing for this one. The code I'm using to rotate them is as follows
IEnumerator CloseDoor()
{
float timer = 1f;
float speed = 30f;
Vector3 pivot = new Vector3(door.transform.position.x, door.transform.position.y,
door.transform.position.z + 1);
while (timer > 0)
{
door.transform.RotateAround(pivot, Vector3.down, speed * Time.deltaTime);
yield return new WaitForSeconds(0.001f);
timer -= Time.deltaTime;
}
}
IEnumerator OpenDoor()
{
float timer = 1f;
float speed = 30f;
Vector3 pivot = new Vector3(door.transform.position.x, door.transform.position.y,
door.transform.position.z + 1);
while (timer > 0)
{
door.transform.RotateAround(pivot, Vector3.up, speed * Time.deltaTime);
yield return new WaitForSeconds(0.001f);
timer -= Time.deltaTime;
}
}

Answer 1

I'll start with some overall advices, regarding your code.
Don't use Time.deltaTime with new WaitForSeconds(...). Time.deltaTime is an amout of time, that passed between Update() calls. But your logic is not inside Update(). You use own time inervals with new WaitForSecons(...), but if the specified amout of time is less then Time.deltaTime, then it will be executed every Time.deltaTime after all Update() calls. It works good for you only because your time interval 0.001f is low enough to be executed every Update(). When your argument in new WaitForSeconts(...) becomes more them Time.deltaTime, the rotation speed of the door becomes too low to door be opened completely. To made your code more clear and safe, return null with yield instruction. In this case, you can be shure, that coroutine will be executed every Update(). More info here.
Your code works with transform positioning, and probably you have physics in your game. All changes with physical object supposed to be done in the FixedUpdate(). In your case your cant return new WaitForFixedUpdate() in yield instruction and use Time.fixedDeltaTime with it.
So speaking about main question. In your code, you are doing pretty unclear and unsafe thing, like hardcoding pivot with global position offset here:
Vector3 pivot = new Vector3(door.transform.position.x, door.transform.position.y,
door.transform.position.z + 1);
Probably, not all doors will have same rotation, and for some of them offset, just with z coordinate will be wrong. Also it becomes wrong after door opening, because the position and rotation of the door changed when you rotating it around some point, that is not the center of the door. So you should base on local transform point, like this:
public class Door : MonoBehaviour
{
private bool _doorOpened = false;
private bool _doorOpening = false;
[SerializeField] // to see in the inspector.
private Vector3 _localDoorRotatePoint = new Vector3(0.5f, 0f, 0f);
// Update is called once per frame
void Update()
{
if (!_doorOpening && Input.GetKeyDown(KeyCode.E))
{
if (!_doorOpened)
{
StartCoroutine(OpenDoor());
}
else
{
StartCoroutine(CloseDoor());
}
}
}
IEnumerator CloseDoor()
{
_doorOpening = true;
var timer = 1f;
var speed = 30f;
// in my case _localDoorRotate point is (0.5f, 0f, 0). In your case it will be like (0, 0, 1f) or something like this.
// remember, that this point is in local transform coordinates, and in scales with this transform scale vector.
var pivot = transform.TransformPoint(_localDoorRotatePoint);
while (timer > 0)
{
transform.RotateAround(pivot, Vector3.down, speed * Time.fixedDeltaTime);
yield return new WaitForFixedUpdate();
timer -= Time.fixedDeltaTime;
}
_doorOpening = false;
_doorOpened = false;
}
IEnumerator OpenDoor()
{
_doorOpening = true;
var timer = 1f;
var speed = 30f;
// in my case _localDoorRotate point is (0.5f, 0f, 0f). In your case it will be like (0f, 0f, 1f) or something like this.
// remember, that this point is in local transform coordinates, and in scales with this transform scale vector.
var pivot = transform.TransformPoint(_localDoorRotatePoint);
while (timer > 0)
{
transform.RotateAround(pivot, Vector3.up, speed * Time.fixedDeltaTime);
yield return new WaitForFixedUpdate();
timer -= Time.fixedDeltaTime;
}
_doorOpening = false;
_doorOpened = true;
}
}
Helpfull links, that can help you with understanding this code:
Transform.TransformPoint
Transform.up