Unity - Add Material To Game Object

Question

I'm am trying to create a script that continuously generates objects and attaches a script to all the generated objects. I want the attached script to after 3 seconds, change the material on the object and add a box collider. My problem is with the material. Since the object was randomly generated, I don't know how to set the material variable. This is my Spawner:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Spawner : MonoBehaviour {
    //Variables
    public float x_max;
    public float x_min;
    public float y_max;
    public float y_min;
    private float Size;
    public float s_max;
    public float s_min;
    public float w_max;
    public float w_min;
    private float ProceduralCacheSize;
    private GameObject sphere;
    private float waitTime = 5f;
    private int fix;

    // Use this for initialization
    void Start () {
        Spawn ();
        Spawn ();
        Spawn ();
        StartCoroutine("MyCoroutine");
    }

    // Update is called once per frame
    void Update () {

    }
    void Spawn(){
            Size = Random.Range (s_min, s_max);
            sphere = GameObject.CreatePrimitive (PrimitiveType.Sphere);
            sphere.transform.position = new Vector3 (Random.Range (x_min, x_max), Random.Range (y_min, y_max), 0);
            sphere.transform.localScale = new Vector3 (Size, Size, Size);
            var fbs = sphere.AddComponent<Astroid> ();
        }

    IEnumerator MyCoroutine(){
        StartCoroutine("Change");
        waitTime = Random.Range (w_min, w_max);
        yield return new WaitForSeconds(waitTime);
        StartCoroutine("MyCoroutine");
        StartCoroutine("Change");
        Spawn ();
    }
}

And this is the script that gets attached:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Astroid : MonoBehaviour {
    //I need to be able to set this variable to a material
    public Material mat;
    // Use this for initialization
    void Start () {
        this.GetComponent<SphereCollider>().enabled = false;
        StartCoroutine("Change");
    }
    // Update is called once per frame
    void Update () {

    }
    IEnumerator Change(){
        yield return new WaitForSeconds (3);
        this.GetComponent<SphereCollider>().enabled = true;
        this.GetComponent<Renderer> ().material = mat;
    }
}

Answer 1

You could just load it from resources

mat = Resources.Load("myMaterial.mat", typeof(Material)) as Material;

Answer 2

You can make a public static int like this. Your Spawner:

 public Material mat; public static Material mat2; void Start(){ mat2 = mat; } 

And in your astroid script:

 using System.Collections; using System.Collections.Generic; using UnityEngine; public class Astroid : MonoBehaviour { //I need to be able to set this variable to a material //public Material mat; // Use this for initialization void Start () { this.GetComponent<SphereCollider>().enabled = false; StartCoroutine("Change"); } // Update is called once per frame void Update () { } IEnumerator Change(){ yield return new WaitForSeconds (3); this.GetComponent<SphereCollider>().enabled = true; this.GetComponent<Renderer> ().material = Spawner.mat2; } }