Weird results with Transform.TransformDirection()-CodePudding

I'm using portal.TransformDirection() to simulate how the object the code is attached to would rotate if it were a child of the portal object without actually being its child.

This is the code and it works kind of but not really. Only if I rotate the portal Object around the Y axis. It still does something when I rotate around the other axes but not what I'm expecting.

I didn't find anyone else who had this problem so I thought I might ask.

I have a short video that demonstrates how it rotates (https://youtu.be/dfvr4IrA2SU) and here is the code on the object that should rotate with the portal object:

using UnityEngine;

[ExecuteInEditMode]
public class PortalArrow : MonoBehaviour
{
    [SerializeField] Transform portal;
    [SerializeField] Vector3 eulerRotation;

    void LateUpdate()
    {
        transform.position = portal.position;
        transform.eulerAngles = portal.TransformDirection(eulerRotation);
    }
}

The variable eulerRotation is just a constant Vector3. nothing special about it.

CodePudding user response：

eulerAngles are no direction and it makes no sense to treat them like one.

The fact that it is also stored as a Vector3 is a pure convinience.

would rotate if it were a child of the portal object without actually being its child.

It sounds like you rather simply want

transform.rotation = portal.rotation;

CodePudding user response：

Your problem is you're using eulerAngles as if it represents a look direction but it does not, it represents three rotations about z, y and z.

Don't use euler angles, just set the rotation directly via transform.rotation and Quaternion.SetLookRotation.

transform.rotation.SetLookRotation(portal.TransformDirection(eulerRotation));

This will correctly apply the look direction rotation.