Vuforia SDK在Unity3d中使用Raycast for ARCamera的问题

Question

I am new to Vuforia.

The gameobject to which the script is added, is a 3d object which is made visible on user-defined triggered image.

I know this is not a new question and I have gone through each of the thread/post on official Vuforia discussion blog for that matter but the problem still persists. And the problem seems very fundamental.

I have the following script attached to my gameobject :

void Update () 
{
    if (Input.touchCount == 1) 
    {
        // Touches performed on screen
        Ray ray;
        RaycastHit hit;
        Debug.Log ("2");
        if(Camera.main != null)
        {
            Debug.Log ("3");
            ray = Camera.main.ScreenPointToRay(Input.GetTouch(0).position);
            hit = new RaycastHit();
            Debug.Log ("33");
            if(Physics.Raycast(ray, out hit))
            {
                Debug.Log ("4");
            }
                   }
            }
    }

When I run the scene and touch on the gameobject, the Debug Console shows

2

3

33

BUT NOT 4. Somehow this ray doesn't hit the object.

This script works fine with the normal camera. Could anyone please shed some light on this.

Thanks

Answer 1

(as far as I can tell) Vuforia doesn't use the ARCamera for collision detection. Instead there is another 'Background Camera' (you can see it if you run your app in Unity and pause it; you'll find it in the Hierarchy pane). To access it use

Camera.allCameras[0] 

instead of

Camera.main

Hope that helps

Answer 2

I think this is a bug between Collider class and ARCamera, but the solution is this:

1. Create a new Scene
2. Create a Cube or any gameobject with collider component.
3. NOT delete the Cube for any reason

4. Test with any hit algorithm(touch or mouse)

    using System.Collections; using UnityEngine; public class rayoPrueba : MonoBehaviour { void start () {print("entro"); } void Update() { Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition); if (Physics.Raycast(ray, 100)) print("Si le jue"); } } 

5. Replace the mainCamera for ARCamera

6. Test Again
7. Put u`r Cube inside ImageTarget and the real model
8. Delete the Cube and lets dance!! I dont know why, but the bug is killed with this ...(Y) ..

The trick is... Never lose a gameObject with Collider Component from the scene..

Answer 3

如果尝试在3D模型上使用RayCast命中目标，则应确保在3D模型上添加Box Collider Component。