Handling collision in child object

I am just starting learning Unity and I am running into problems with compound colliders. I created an empty game object and added a cube as its child. I attach a rigidbody on the parent and a collider to the child. I attached scripts on both the parent and the child, but I can only seem to get collision events on the parent. I am really confused about this. (I tried adding a rigidbody to the child as well, but that seems to make the object falls right through the floor for some reason. The child does fire off an collision event in this case.)

Both the parent and the child has code like this:
using UnityEngine;
using System.Collections;

public class test : MonoBehaviour {

	// Use this for initialization
	void Start () {
	// Update is called once per frame
	void Update () {

    void OnCollisionEnter(Collision other)
        Debug.Log("full collision");

From what I understand you want multiple children in an object, and detect collisions individually for the children. For that you need to attach a rigidbody to each of the children. Otherwise the collisions will go up the hierarchy and register at the first rigidbody. :slight_smile: