Rotate Object around itself (tunnel)

Hello Guys.

I'm trying to make a tunnel (where a spaceship will travel into).

The controls will rotate THE TUNNEL, for the player to avoid obstacles.

Thing is, the tunnel is rotating around a wrong axis and not itself.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class Controller : MonoBehaviour
6. {
7.  
8.     // Start is called before the first frame update
9.     void Start()
10.     {
11.      
12.     }
13.  
14.     // Update is called once per frame
15.     void Update()
16.     {
17.         if (Input.GetKey(KeyCode.A)) {
18.             transform.Rotate (0, 50 * Time.deltaTime, 0, Space.Self);
19.         }
20.  
21.         if (Input.GetKey(KeyCode.D)) {
22.         transform.Rotate(0, -50 * Time.deltaTime, 0, Space.Self);
23.         }
24.     }
25. }
26.  

This code is within the tunnel (which is the parent of the cylinder model and an obstacle.

Here's the behaviour

 

Wrong pivot point, I mean

 

See at the top there, just to the right of your translate/rotate/scale buttons, there's a button that says "Center"? Click that so it says "Pivot" and select your tunnel object.

The point where the three axes meet is the pivot point setup for that object. If you made this model, you didn't set its origin point to be centered around its long axis. If you got this model from somewhere else, you'll have to either find a different one or open it in a modeling tool to edit the origin yourself.

You could just make the tunnel a child of an empty gameobject and try to position it so that the empty object's origin is aligned with where the tunnel's origin should be, but that sounds like too much of a PITA to me.

 

OMG THAT WAS IT!
I've altered my Blender moldel. Thank you SO MUCH <3