Placing an object in front of the camera - unity3d

Question

This should be an easy task, and I have googled it, but I can't figure out why any of the examples are working for me.
Basically, I want to place tiles on the ground in my first person game. I want the object I want to place on the ground to "float" in mid-air while choosing the perfect location for it. I can instantiate the object, make it a child of the player camera, but I'm unable to position it X units in front of the camera; it always ends up "on" the player;
public void StartPlacing ( Item item ) {
Object itemPrefab = Resources.Load( "Prefabs/" + item.prefabName );
GameObject itemObject = (GameObject)Instantiate( itemPrefab );
itemObject.transform.parent = playerCamera.transform;
// What to do here to place it in front of the camera? I've tried this:
itemObject.localPosition = new Vector3( 0, 0, 5 );
}
UPDATE: The camera is a child of the player (Character Controller), and the camera is in perspective mode.

Answer 1

You could use the forward vector of the object, something like this:
public GameObject frontObject;
public float distance;
void Update () {
frontObject.transform.position = Camera.main.transform.position + Camera.main.transform.forward * distance;
}

Answer 2

Thanks for all the useful suggestions, everyone! I came up with the following code which suits my needs:
using UnityEngine;
using System.Collections;
public class ConstructionController : MonoBehaviour {
private Camera playerCamera;
private GameObject itemObject;
private float distance = 3.0f;
// Use this for initialization
void Start () {
playerCamera = GetComponentInChildren<Camera>();
}
// Update is called once per frame
void Update () {
if ( itemObject != null ) {
itemObject.transform.position = playerCamera.transform.position + playerCamera.transform.forward * distance;
itemObject.transform.rotation = new Quaternion( 0.0f, playerCamera.transform.rotation.y, 0.0f, playerCamera.transform.rotation.w );
}
}
// Start constructing an item
public void StartConstructingItem ( Item item ) {
Object itemPrefab = Resources.Load( "Prefabs/" + item.prefabName );
itemObject = (GameObject)Instantiate( itemPrefab );
}
}