Collider does not call callback functions

Question

I have a script that will create new GameObjects and will place it where the mouse is placed on the terrain. Now I need to have a check for collision on other already placed GameObjects on the field.

I check different tutorials and documentation and cannot find a way to do this in code.

My code looks like:

objectToPlace = (GameObject)AssetDatabase.LoadAssetAtPath("Assets/Game/3D Models/Buildings/" + objectName + ".fbx", typeof(GameObject));
objectToPlace.SetActive(true);
objectToPlace.transform.localScale = new Vector3(1, 1, 1);
objectToPlace = Instantiate(objectToPlace);

objectToPlace.transform.Rotate(Vector3.right * 90);

BoxCollider collider = (BoxCollider)objectToPlace.AddComponent(typeof(BoxCollider));
collider.isTrigger = true;

In the same class as the above code I have OnTriggerEnter function. But that function is not called. How can I link the Collider to that function in Unity 5.6?

I also tried using the Physics.CheckBox for checking if my new create gameObject does not collide to any other object. But without any succes.

Answer 1

I created a custom class for the collision detection with the OnTriggerExit, OnTriggerStay and OnTriggerEnter funtions. Also in my class where I place my models I added:

objectToPlace.AddComponent(typeof(BuildingColliderHandler));