HELP. Camera Movement vs. NPC detection.

For a school assignment we've been asked to redesign the Stealth map using the knowledge we've learned from watching a few tutorial videos. (Mind me, that is hardly any knowledge at all, so forgive me in advance).

Okay. After recreating the Stealth tutorial perfectly, I changed around the map using different models and walls from the asset store. After recreating this new map, I created a new nav-mesh so that the NPC's would have somewhere to go and patrol, but here is where the problem comes in.

I can either: a. Change the layer of all my walls and objects to "Ignore Raycast" so that my camera does not stop when it detects a model, and watches my player move into the distance, slowly becoming microscopic. or b. Keep it enabled, because when ray cast is ignored, my robot guard NPC's can detect my movement through walls, and proceed to shoot me through them also.

This is why I've come to ask you guys. I've got the amount of knowledge that is sufficient to move a few walls and lights around, and maybe make a few new components and meshes, but I have no idea on how to re-code the camera movement script to use a different method of obstacle direction. (Preferably, I don't care if the camera detects an obstacle, I just want it to pan around above my player, following where he goes).

All In all, is there a way to recode the camera movement script so that I don't need to sacrifice letting NPC's see me and shoot me through my objects that are ignoring ray-cast? If so, can anyone fix it for me?

Thank-you in advance for any work you put into this, as I'm sure everyone has something better to do and it would be a great sacrifice of time.

I will post my Camera Movement script below, and feel free to make any changes to it you find necessary.

 using UnityEngine;
 using System.Collections;
 
 public class CameraMovement : MonoBehaviour
 {
     public float smooth = 1.5f;            
     
     
     private Transform player;            
     private Vector3 relCameraPos;        
     private float relCameraPosMag;        
     private Vector3 newPos;                
 
     
     void Awake ()
     {
         player = GameObject.FindGameObjectWithTag(Tags.player).transform;
         
         relCameraPos = transform.position - player.position;
         relCameraPosMag = relCameraPos.magnitude - 0.5f;
     }
     
     
     void FixedUpdate ()
     {
         Vector3 standardPos = player.position + relCameraPos;
         
         Vector3 abovePos = player.position + Vector3.up * relCameraPosMag;
         
         Vector3[] checkPoints = new Vector3[5];
         
         checkPoints[0] = standardPos;
         
         checkPoints[1] = Vector3.Lerp(standardPos, abovePos, 0.25f);
         checkPoints[2] = Vector3.Lerp(standardPos, abovePos, 0.5f);
         checkPoints[3] = Vector3.Lerp(standardPos, abovePos, 0.75f);
         
         checkPoints[4] = abovePos;
         
         for(int i = 0; i < checkPoints.Length; i++)
         {
             if(ViewingPosCheck(checkPoints[i]))
                 break;
         }
         
         transform.position = Vector3.Lerp(transform.position, newPos, smooth * Time.deltaTime);
         
         SmoothLookAt();
     }
     
     
     bool ViewingPosCheck (Vector3 checkPos)
     {
         RaycastHit hit;
         if(Physics.Raycast(checkPos, player.position - checkPos, out hit, relCameraPosMag))
             if(hit.transform != player)
                 return false;
         
         newPos = checkPos;
         return true;
     }
     
     
     void SmoothLookAt ()
     {
         Vector3 relPlayerPosition = player.position - transform.position;
         
         Quaternion lookAtRotation = Quaternion.LookRotation(relPlayerPosition, Vector3.up);
         
         transform.rotation = Quaternion.Lerp(transform.rotation, lookAtRotation, smooth * Time.deltaTime);
     }
 }