Mismatch between OverlapBox and Gizmo

Questions & Answers
1

I want to use OverlapBox to create a box in front of a vehicle and be able to check collision on demand. I use draw gizmo to be able to see the size and position of the box to confirm that size and position are correct.

This is my code:

public class TestCollision : MonoBehaviour
{
[Header("Collision")]
public Vector3 m_DetectorOffset = Vector3.zero;
public Vector3 m_DetectorSize = Vector3.zero;

private LayerMask m_LayerMask;
private Renderer m_Renderer = null;

void Start()
{
    m_LayerMask = (1 << LayerMask.NameToLayer("Pedestrian")) | (1 << LayerMask.NameToLayer("Vehicle"));

    m_Renderer = GetComponent<Renderer>();
    m_Renderer.material.color = Color.green;
}

private void FixedUpdate()
{
    if (CheckForCollisions())
        m_Renderer.material.color = Color.red;
    else
        m_Renderer.material.color = Color.green;
}

public bool CheckForCollisions()
{
    Vector3 colliderPos = transform.position + m_DetectorOffset;

    Collider[] colliders = Physics.OverlapBox(colliderPos, m_DetectorSize, transform.rotation, m_LayerMask);

    if (colliders.Length == 1)
    {
        // Ignore collision with itself
        if (colliders[0].gameObject == gameObject)
            return false;

        return true;
    }

    if (colliders.Length > 0)
        return true;

    return false;
}

#if UNITY_EDITOR
protected virtual void OnDrawGizmos()
{
    Gizmos.color = Color.red;
    Gizmos.matrix = transform.localToWorldMatrix;
    Gizmos.DrawWireCube(m_DetectorOffset, m_DetectorSize * 2.0f);
}
#endif
}

This script works great if I don’t rotate the “vehicle” - in the picture the blue cube is the object I want to detect, the green/red cube is the vehicle and the red wireframe box is the OverlapBox represented by the gizmo:
alt text

The issue occurs when the “vehicle” rotates - in the following picture I rotate the vehicle 90 degrees in the Y axis, the gizmo represents the box in the correct position, however the OverlapBox logic is ignoring such rotation (even though when the rotation of the object is passed in the function):
alt text

How can I make the OverlapBox to work properly taking rotation into consideration and being able to represent an accurate gizmo.

Many thanks in advance.

2

this will work, you need to transform the position

public bool CheckForCollisions()
{
    Vector3 colliderPos = transform.TransformPoint(m_DetectorOffset);

    Collider[] colliders = Physics.OverlapBox(colliderPos , m_DetectorSize, transform.rotation);

    if (colliders.Length == 1)
    {
        // Ignore collision with itself
        if (colliders[0].gameObject == gameObject)
            return false;

        return true;
    }

    if (colliders.Length > 0)
        return true;

    return false;
}