How do I move a prefab(clone) in a non attached script

Question

I'm trying to Instantiate a clone in a master control script and get it to move. I can't figure out how to affect the instantiated clone.

using UnityEngine; using System.Collections;

public class MasterScript : MonoBehaviour {

 public Rigidbody2D cat;
 public float speed = 10f;

 // Use this for initialization
 void Start () {
 
     cat = (Rigidbody2D)Instantiate (cat, transform.position, transform.rotation);
     cat.transform.Translate(Vector2(0,speed));

 }

}

I'm sure this is easy it's just beyond me for some reason.

Answer 1

Answer by Burla · Apr 17, 2014 at 09:06 PM

Are there any particular reason to why you're casting it to/as a Rigidbody2D?

A Rigidbody doesn't have a transform. You should make it a GameObject instead as it has a transform.

 public GameObject cat;

 cat = Instantiate(cat, transform.position, transform.rotation);
 cat.transform.Translate(Vector2(0, speed));

Try doing it this way. Please let me know if this solved your problem. Please feel free to correct me if I'm wrong on this.

Add comment · Show 4 · Share

robertbu · Apr 17, 2014 at 09:09 PM 1

Share

@Burla - a Rigidbody does have a transform. Or put another way, a Rigidbody is a component and therefore cannot exist without a game object. Therefore the game object the Rigidbody is attached to will have a transform. And you can access that Transform through the rigidbody.

everettdale · Apr 17, 2014 at 10:09 PM 0

Share

Still not working. I may have not given enough information.

First no reason for the Rigidbody2D except that was what I thought I needed.

Second This script is attached to an empty game object, no the prefab or the clone. (if that matters)

Third All I want to do it Instantiate an object then control it as simply as possible.

However the above suggestion does not work either. Here is the new code and the errors

 using UnityEngine;
 using System.Collections;
 
 public class MasterScript : MonoBehaviour {
 
     public GameObject cat;
     public float speed = 10f;
 
     // Use this for initialization
     void Start () {
     
         cat = Instantiate(cat, transform.position, transform.rotation);
         cat.transform.Translate(Vector2(0, speed));
 
     }
 
 }

I get these errors

Assets/Scripts/MasterScript.cs(12,17): error CS0266: Cannot implicitly convert type UnityEngine.Object' to UnityEngine.GameObject'. An explicit conversion exists (are you missing a cast?)

Assets/Scripts/MasterScript.cs(13,41): error CS0119: Expression denotes a type', where a variable', value' or method group' was expected

Assets/Scripts/MasterScript.cs(13,31): error CS1502: The best overloaded method match for UnityEngine.Transform.Translate(UnityEngine.Vector3)' has some invalid arguments Assets/Scripts/MasterScript.cs(13,31): error CS1503: Argument #1' cannot convert object' expression to type UnityEngine.Vector3'

robertbu · Apr 17, 2014 at 10:11 PM 0

Share

Change lines 12 and 13 as follows to get rid of the errors:

 cat = Instantiate(cat, transform.position, transform.rotation) as GameObject;
 cat.transform.Translate(new Vector2(0, speed));

Note the translate is only going to cause the Instantiated object to move once. If you have a rigidbody, you may want to use cat.rigidbody.AddForce() to get it to move and continue to move.

Burla · Apr 18, 2014 at 10:23 AM 0

Share

@robertbu - Ah, okay. I didn't know that you can access the transform through the rigidbody. Does that mean that you can do it the other way too - access the rigidbody through a transform as they're both components of a GameObject?

Answer 2

Answer by everettdale · Apr 19, 2014 at 07:43 AM

Ok. I made these changes to lines 12 and 13

cat = Instantiate(cat, transform.position, transform.rotation) as GameObject; cat.transform.Translate(new Vector2(0, speed));

The object shows up as cat(clone) but does nothing. I get this error while the game is running

NullReferenceException: Object reference not set to an instance of an object MasterScript.Start () (at Assets/Scripts/MasterScript.cs:13)

I don't understand why this is so difficult. It seems like a basic idea. Create an object in the scene and make it move, from point a to point b or whatever. I'd think this would be a common thing to do in most games.

Add comment · Share

Answer 3

Answer by SkyforceP · Feb 05, 2016 at 04:41 PM

Hi, i have the same problem, my main object moves but its clones not. I do it in this way

1)Generating my cubes on the scene

 public class random_generating : MonoBehaviour {
 
     public GameObject Cube;
 
     // Use this for initialization
     void Start () {
         for(int i=0; i<5; i++)
         Instantiate (Cube,new Vector3(1.5f,3.34f,0.0f),Quaternion.identity);    
     }
     
 }

2)Cube moving

 public class cube_moving : MonoBehaviour {
 
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update () {
         transform.Translate (0, 0, Time.deltaTime*(-5));
         //transform.Translate(0, Time.deltaTime, 0, Local.World);
     }
 }

I know that my piece of advice does not allow your problem, but as another idea can little inspire you for smth else(sorry for my english, i am ukranian))

Add comment · Share

How do I move a prefab(clone) in a non attached script

3 Replies

Your answer

Welcome to Unity Answers

Follow this Question

Related Questions