How to add to scene own gameobject on unity

Question

I create my own cube. I use below code to do it

void Start () {

    MeshFilter meshFilter = gameObject.GetComponent<MeshFilter>();
    Mesh mesh = new Mesh ();
    meshFilter.mesh = mesh;

    mesh.vertices = new Vector3[]{
        // face 1 (xy plane, z=0)
        new Vector3(0,0,0), 
        new Vector3(1,0,0), 
        new Vector3(1,1,0), 
        new Vector3(0,1,0), 
        // face 2 (zy plane, x=1)
        new Vector3(1,0,0), 
        new Vector3(1,0,1), 
        new Vector3(1,1,1), 
        new Vector3(1,1,0), 
        // face 3 (xy plane, z=1)
        new Vector3(1,0,1), 
        new Vector3(0,0,1), 
        new Vector3(0,1,1), 
        new Vector3(1,1,1), 
        // face 4 (zy plane, x=0)
        new Vector3(0,0,1), 
        new Vector3(0,0,0), 
        new Vector3(0,1,0), 
        new Vector3(0,1,1), 
        // face 5  (zx plane, y=1)
        new Vector3(0,1,0), 
        new Vector3(1,1,0), 
        new Vector3(1,1,1), 
        new Vector3(0,1,1), 
        // face 6 (zx plane, y=0)
        new Vector3(0,0,0), 
        new Vector3(0,0,1), 
        new Vector3(1,0,1), 
        new Vector3(1,0,0), 
    };

    int faces = 6; // here a face = 2 triangles

    List<int> triangles = new List<int>();
    List<Vector2> uvs = new List<Vector2>();

    for (int i = 0; i < faces; i++) {
        int triangleOffset = i*4;
        triangles.Add(0+triangleOffset);
        triangles.Add(2+triangleOffset);
        triangles.Add(1+triangleOffset);

        triangles.Add(0+triangleOffset);
        triangles.Add(3+triangleOffset);
        triangles.Add(2+triangleOffset);

        // same uvs for all faces
        uvs.Add(new Vector2(0,0));
        uvs.Add(new Vector2(1,0));
        uvs.Add(new Vector2(1,1));
        uvs.Add(new Vector2(0,1));
    }

    mesh.triangles = triangles.ToArray();
    mesh.uv = uvs.ToArray();

    GetComponent<Renderer>().material = new Material(Shader.Find("Diffuse"));

    mesh.RecalculateNormals(); 
    mesh.RecalculateBounds (); 
    mesh.Optimize();

I want to add this object many times at runtime. I create a prefab by click right button on editor. I drag gameobject to it. I create a member variable public Gameobject prefab. I drag prefab to member variable on inspector.

I want to add 2 cube on my scene. I use below code but it doesn't work for me. It adds many objects.

enter image description here

I use below code clone and add object

prefab = gameObject;
//  for (int i = 0; i < 3; i++) {
    gO = Instantiate (prefab, new Vector3 (0 * 1.8F - 8.2f, 0, 0), Quaternion.identity) as GameObject;
//  }

How can I create a prefab from my own gameobject? How can I add it to scene at runtime properly? EDIT

If I create unity shape from editor, and I drag it to prefab, I can add many object on C# code. But I can't do same work for my own cube.

It looks like you are doing something wrong Instantiating your prefab. Do you have the script with the Instantiate Code attached to your prefab? - So the after instantiating the prefab it will recursivly instantiate the next one? — Marius Junak
No, I have only one .cs file. And it attached to gameObject. I instantiate only one time but it recursively instantiate. — zakjma
I'm not shure if i understand your setting right. - You should have one CS-File "BuildCubeMesh.cs" on your prefab. with the code in your upper example. And then you have a script "CubeBuilder.cs" With the code below in the Start-method and a reference to your prefab. — Marius Junak
I undo my code and scene. I have a test.cs file, it draw a cube upper code. My scene has a main camera and gameObject. This cs file attached to gameObject. What should I do now? (There is not any prefab object yet) — zakjma
Ok. - 1. Pull the gameObject into the "Project"-Window, it will be automatically converted into a prefab. Now delete the gameObject from your Scene. 2. Make a new empty Gameobject and add a new Script "TestFactory.cs" and add the bottom code from your post to the Start Method. 3. Add the Prefab you created earlier in the inspector => Start the Scene — Marius Junak

Marius Junak Marius Junak · Accepted Answer · 2015-06-03T13:57:47

So in the end you have 2 Scripts:

public class CubeFactory : MonoBehaviour
{
     public GameObject PrefabToCreate;
     // Use this for initialization
     void Start () {
     var cube = Instantiate(PrefabToCreate, new Vector3(0 * 1.8F - 8.2f, 0, 0), Quaternion.identity) as GameObject;
    }

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

    }
}

and

public class Cube : MonoBehaviour
{
    private void Start()
    {

        MeshFilter meshFilter = gameObject.GetComponent<MeshFilter>();
        Mesh mesh = new Mesh();
        meshFilter.mesh = mesh;

        mesh.vertices = new Vector3[]
        {
            // face 1 (xy plane, z=0)
            new Vector3(0, 0, 0),
            new Vector3(1, 0, 0),
            new Vector3(1, 1, 0),
            new Vector3(0, 1, 0),
            // face 2 (zy plane, x=1)
            new Vector3(1, 0, 0),
            new Vector3(1, 0, 1),
            new Vector3(1, 1, 1),
            new Vector3(1, 1, 0),
            // face 3 (xy plane, z=1)
            new Vector3(1, 0, 1),
            new Vector3(0, 0, 1),
            new Vector3(0, 1, 1),
            new Vector3(1, 1, 1),
            // face 4 (zy plane, x=0)
            new Vector3(0, 0, 1),
            new Vector3(0, 0, 0),
            new Vector3(0, 1, 0),
            new Vector3(0, 1, 1),
            // face 5  (zx plane, y=1)
            new Vector3(0, 1, 0),
            new Vector3(1, 1, 0),
            new Vector3(1, 1, 1),
            new Vector3(0, 1, 1),
            // face 6 (zx plane, y=0)
            new Vector3(0, 0, 0),
            new Vector3(0, 0, 1),
            new Vector3(1, 0, 1),
            new Vector3(1, 0, 0),
        };

        int faces = 6; // here a face = 2 triangles

        List<int> triangles = new List<int>();
        List<Vector2> uvs = new List<Vector2>();

        for (int i = 0; i < faces; i++)
        {
            int triangleOffset = i*4;
            triangles.Add(0 + triangleOffset);
            triangles.Add(2 + triangleOffset);
            triangles.Add(1 + triangleOffset);

            triangles.Add(0 + triangleOffset);
            triangles.Add(3 + triangleOffset);
            triangles.Add(2 + triangleOffset);

            // same uvs for all faces
            uvs.Add(new Vector2(0, 0));
            uvs.Add(new Vector2(1, 0));
            uvs.Add(new Vector2(1, 1));
            uvs.Add(new Vector2(0, 1));
        }

        mesh.triangles = triangles.ToArray();
        mesh.uv = uvs.ToArray();

        GetComponent<Renderer>().material = new Material(Shader.Find("Diffuse"));

        mesh.RecalculateNormals();
        mesh.RecalculateBounds();
        mesh.Optimize();
    }
}

in your Scene you have your Camera and a GameObject with the CubeFactory on it.

Before you have to make a Prefab. Wich contains a GameObject with the "Cube.cs" Script on it.

Add the prefab as "PrefabToCreate" to your Cubefactory in the inspector.

How to add to scene own gameobject on unity

1 Answers