Find points without obstacles on 3D map

// The last detected location without obstacles 
    Vector3 strkeFlyPos;

    // The rotation angle of the vector each time 
    public float rotationAngle = 180;

    // The direction of the vector  , Express x The positive direction of the axis 
    Vector3 dirTarget = new Vector3(5, 0, 0);
    // The length of the vector 
    float _v3Lenght = 5;

    // Target location 
    Vector3 _target;

    /// <summary>
    ///  Find a point that has no obstacles on the map with itself as the origin 
    /// </summary>
    /// <param name="_angle"></param>
    public void StrkeFly(float _angle)
    {
        for (int i = 0; i < 360 / _angle; i++)
        {

            // Temporarily record the position of the current point found   // Let yourself add a radius ( This radius is just a left side with 5 The direction vector of ), Let this vector rotate , Get a circular point around yourself 
            Vector3 tempPos = transform.position + Quaternion.AngleAxis(_angle * i, transform.up) * dirTarget.normalized * _v3Lenght;

            // A ray is emitted from the camera to detect whether the point is an obstacle 
            Ray ray = new Ray(Camera.main.transform.position, tempPos - Camera.main.transform.position);
            RaycastHit hit;

            if (Physics.Raycast(ray, out hit))
            {
                // If not, let the enemy be hit and fly to this point 
                if (hit.transform.tag == "ground")
                {
                    _target = hit.point;

                    // Method of calling base note after finding target position 
                    StartCoroutine("FlyTaget");
                    return;
                }

            }
        }
        // After a week of searching , Can't find , Then reduce the rotation angle of the vector , And call itself 
        if (_angle > 1)
        {
            StrkeFly(_angle / 2);
            return;
        }
        // When the angle is less than 1 I haven't found it yet , Then reduce the length of the vector and keep looking 
        if (_angle < 1 && _v3Lenght > 1)
        {
            _v3Lenght -= 1;
            StrkeFly(_angle);
            return;
        }

    }