Unity 3D Collisiondetection

Question

I generate an Gameobjct array of speheres and try to apply a collider to them to detect collision with my character controller.

i tried serverel methods, nothing worked. Why Unity doent detect the collision ?

Script for generating the array :

 public GameObject[] Chunkzufall(float l, float b, int n)
{
    GameObject chunk = new GameObject();
    GameObject[] chunks = new GameObject[n];

    chunkSpeed = new float[n];
    chunkMaxH = new float[n];
    chunkMinH = new float[n];

    for (int j = 0; j < n; j++)
    {
        float h = 1;
        float posX = Random.Range(0.0f, b);
        float posZ = Random.Range(0.0f, l);

        GameObject group = Chunk(h);
        group.transform.Translate(posX, 0.0f, posZ);

        group.transform.parent = chunk.transform;
        chunk.tag = "reset";
        chunk.name = "chunk";

        chunkSpeed[j] = (float) Random.Range(-0.04f, 0.04f);
        chunkMaxH[j] = (float) Random.Range(2.0f, 10.0f);
        chunkMinH[j] = (float) Random.Range(-2.0f, -10.0f);

        chunk.AddComponent<SphereCollider>();
        chunk.GetComponent<SphereCollider>().isTrigger = true;
        chunk.GetComponent<SphereCollider>().radius = 5.0f;

        chunks[j] = chunk;

    }
    return chunks;
}

public void MoveChunks(GameObject[] chunks)
{
    int i = 0;
    foreach(GameObject chunk in chunks)
    {
        Vector3 position = chunk.transform.GetChild(i).position;

        if (position.y >= chunkMaxH[i] || position.y <= chunkMinH[i])
        {
            chunkSpeed[i] = chunkSpeed[i] * -1;
        }

        position.y = position.y - chunkSpeed[i];
        chunk.transform.GetChild(i).position = position;
        chunk.GetComponent<SphereCollider>().center = position;

        i++;
    }
    i = 0;
}

collision trigger function :

    private void OnTriggerEnter(Collider col) {
    if(col.gameObject.tag == "reset") {
        transform.position = new Vector3(startX, startY, startZ);
        Debug.Log("chunk");
    }
}

Answer 1

To detect a trigger on the dynaimcally created object, you have to enable the IsTrigger flag, add collider to the object. The object must also have Rigidbody attached to it. It looks like you already have the IsTrigger flag and a collider but you are missing Rigidbody .

Replace this:

chunk.AddComponent<SphereCollider>();
chunk.GetComponent<SphereCollider>().isTrigger = true;
chunk.GetComponent<SphereCollider>().radius = 5.0f;

with

chunk.AddComponent<SphereCollider>();
chunk.AddComponent<Rigidbody>(); //ADDS RIGIDBODY COMPONENT
chunk.GetComponent<SphereCollider>().isTrigger = true;
chunk.GetComponent<SphereCollider>().radius = 5.0f;

Answer 2

Do you have Rigidbody attached? The objects need Rigidbody attached to it to be able to detect collision. And do note that for each pair of collider and collided objects, having one of them with Rigidbody attached is enough to capture the event. In your case, if you don't want to process the collision betweens spheres, then attach Rigidbody to your character object is good enough.

Answer 3

You could add a RigidBody to all of the spheres but that would be very inefficient if you want to have many of them. It is enough to have 1 RigidBody for every 2 objects that you want to check collision against.

So in your case it would be enough to put a RigidBody component on your character controller object.

Also, make sure the RigidBody is not set to Kinematic.