Gameobjects disappearing when changing renderer.material.color

Question

I'm generating an array of objects using this code:

    while(currentPosition.z < poolSize){
        var ringObj = GameObject.Instantiate(ring) as GameObject;          
        ringObj.transform.position = currentPosition;
        ringObj.GetComponent<Renderer>().material.color =  new Color (1.0f, 0f, 0f);
        // Adds the ring to the pool.
        pool[(int)currentPosition.z] = ringObj;
        updateCurrentPosition ();
    }

This works fine without this line:

ringObj.GetComponent<Renderer>().material.color =  new Color(Random.Range(0.0f,1.0f), Random.Range(0.0f,1.0f), Random.Range(0.0f,1.0f));

Which should randomize the color of the object. The problem is that instead of doing this, the whole code would generate only one object (I can see it on the hierarchy view) with the standard material color and then stops the generation. Also, the material is not changing color.

I can't understand why this happens. Can someone explain this to me, please? I'm using Unity 5.3.4f1. Thank you.

Answer 1

Place this on an empty GameObject in the scene:

public class TestColourAndPosition : MonoBehaviour
{
    void Start ()
    {
        for (int i = 0; i < 10; i++)
        {
            GameObject cube = GameObject.CreatePrimitive(PrimitiveType.Cube);   
            cube.transform.position = new Vector3(i * 2.0f, 0, 0);
            cube.GetComponent<Renderer>().material.color =  new Color(Random.Range(0.0f,1.0f),Random.Range(0.0f,1.0f),Random.Range(0.0f,1.0f));
        }
    }

    void Update ()
    {
    }
}

...No problem with generating random material colours or simple GameObject positioning.

So I suspect your problem comes before that, and is corrupting some values leading to the crash.

I suggest you use the above and work slowly and steadily back toward what you want. And don't call updateCurrentPosition() (in Update() or LateUpdate()) until you can position the objects statically / once off, without experiencing any problems. And switch in your 3D model only once all else is working, in case there is a model problem - unlikely, but possible.

Morals of the story When stumped, revert to a minimal test case and make your way from there. Always test incrementally as you code - so you know the exact change where things begin to fail.