Collision won't trigger with instantiated objects

Hi,
I'm generating a terrain and instantiating an object on top of it that spins randomly.
Because i'm spinning randomly I need to be able to find when the objects collide with the floor and the lowest point of my mesh.
the extent of the renderer.bounds are always 0,0,0.
the collision function is never called.

I have been struggling with this for hours now

Code (CSharp):

1.  // Start is called before the first frame update
2.     void Start() {
3.         StartCoroutine(WaitForManager());
4.     //GENERATING TERRAIN
5.         TerrainData TData = new TerrainData();
6.         float[,] heightmap = new float[32, 32];
7.         TData.SetHeights(0, 0, heightmap);
8.         TData.size = new Vector3(256, 1, 256);
9.         var TerrainCreated = Terrain.CreateTerrainGameObject(TData);
10.         TerrainCreated.AddComponent<Rigidbody>();
11.         TerrainCreated.GetComponent<Rigidbody>().useGravity = false;
12.     //FETCH THE OBJECTS
13.         ObjList = Resources.LoadAll("Models", typeof(GameObject));
14.  
15.         InstantiateObj(ObjList[0]);
16.        
17.     }
18.  
19.     void InstantiateObj(Object obj)
20.     {
21.     //INSTANTIATE AN OBJECT + ALL THE NEEDED COMPONENTS
22.         pos = new Vector3(0, 1, 0);
23.         var ObjCreated = (GameObject)Instantiate(ObjList[0], pos, Quaternion.identity);
24.         ObjCreated.AddComponent<MeshFilter>();
25.         MeshFilter Mesh = ObjCreated.GetComponent<MeshFilter>();
26.         ObjCreated.SetActive(true);
27.         ObjCreated.AddComponent<MeshCollider>();
28.         ObjCreated.AddComponent<MeshRenderer>();
29.         ObjCreated.GetComponent<MeshCollider>().sharedMesh = Mesh.mesh;
30.         ObjCreated.GetComponent<MeshCollider>().convex = true;
31.         ObjCreated.AddComponent<Rigidbody>();
32.         ObjCreated.GetComponent<Rigidbody>().useGravity = false;
33.         ObjCreated.GetComponent<Rigidbody>().isKinematic = true;
34.         ObjCreated.AddComponent<randomRot>();
35.     }

Code (CSharp):

1.  //SCRIPT APPLIED AS COMPONENT TO THE OBJECT
2. Renderer rend;
3. void OnCollisionStay(Collision jeej)
4.     {
5.         print("lol");
6.     }
7.  
8.     void Update()
9.     {
10.         rend = GetComponent<Renderer>();
11.         print(rend.bounds);
12.     }

 

Don't your terrain also need a collider?

 

There's a terrain collider and I also tried with a box collider

 

Have you tried OnCollisionEnter(), and OnCollisionExit()?

Why by the way does the terrain have a rigidbody?