You want a minimap camera stay over the player and look downwards to the ground?
The camera follows the player in X and Z direction, and the minimap should always pointing upwards with “north”?
If i am right, try something like this:
Do not parent the two cameras and add a script like this to the miniMap camera:
using UnityEngine;
using System.Collections;
public class miniMapFollow : MonoBehaviour {
public float miniMapSize = 50.0f; // distance from ground to camera
void Update () {
Vector3 camPos = Camera.main.transform.position;
transform.position = new Vector3(camPos.x, miniMapSize, camPos.z);
}
}
with this you set the x and z position of the miniMap camera to the position of the main camera.
With the miniMapSize value you set the y position. Get closer to the ground will zoom into the miniMap.