I have a problem that I’ve yet been able to solve, and although I know how to approach the problem, I don’t know any Vector math to know if I’m doing the mathematics right.

I have a camera (C) that is always facing the same direction. I have an object (A) with a child (B). A can face any direction in the XZ-plane, and B can face any direction relative to A in the same local XZ-plane. A and B orientation, so their Up direction is the same always. However A can tilt relative to C.

The Problem: How do I rotate Object A so that object B will face the camera at the end of the rotation regardless of which direction B is facing?

My current approach:

I find the angle between the forward vector of the Camera C and A, and the angle between the A and B. I then rotate A based on the combined difference (this part I’m not sure)?

```
private async Task RotateCartToCamera(ARDrawerData _drawer)
{
float angleCamToDrawer = Vector3.Angle(nonARCamera.gameObject.transform.forward, _drawer.gameObject.transform.forward);
float angleCartToDrawer = Vector3.Angle(arGameController.Cart.transform.forward, _drawer.gameObject.transform.forward);
float total = angleCamToDrawer + angleCartToDrawer;
if (total > 180f)
total = -(180 - total);
Vector3 startRot = nonARCartRotate.transform.forward;
Vector3 destRot = nonARCartRotate.transform.forward + new Vector3(0f, total, 0f);
ARTestModeStatics.DebugMessage("Angle : " + Vector3.Angle(startRot, destRot));
while (Vector3.Angle(startRot, destRot) > 1f)
{
if (cancel.IsCancellationRequested)
break;
startRot = Vector3.RotateTowards(startRot, destRot, Mathf.Rad2Deg * rotateSpeed * Time.deltaTime, 0f);
nonARCartRotate.transform.localRotation = Quaternion.Euler(startRot);
ARTestModeStatics.DebugMessage("Angle: " + Vector3.Angle(startRot, destRot));
if (Vector3.Angle(startRot, destRot) <= 1f)
{
ARTestModeStatics.DebugMessage("Rotation completed.");
nonARCartRotate.transform.localRotation = Quaternion.Euler(destRot);
break;
}
await Task.Delay(1);
}
}
```

This code isn’t giving me the results I expected. Its rotating wrong, and the final angle is completely off. What am I doing wrong? Or is there an easier approach to this? I’m trying not to use Quaternions because I don’t understand any of it.