How to find a Child Gameobject by name?

Question

Hi, how can i find a second child of a gameobject by name?

this is the part of the code:

     function Update (){
 
     var ray : Ray = playerCamera.ViewportPointToRay (Vector3(0.5,0.5,0));
     var hit : RaycastHit;
 
     if (Physics.Raycast (ray, hit, distanceDetection)){
 
         if(hit.transform.name == "Bone"){
 
             target = true;
 
         } else {
 
             target = false;    
         }
 
     } else {
 
         target = false;
     }
 }

I need to find the child of a child gameobject named "Bone", but i cant find it this way.

Answer 1

Best Answer

Answer by aldonaletto · Nov 06, 2011 at 11:25 PM

You can specify the path name to find a "grandchild", like in the Transform.Find example:

   aFinger = transform.Find("LeftShoulder/Arm/Hand/Finger");

But if you have more than one child with the same name, you can iterate through all children comparing the names or tags:

   for (var child in transform){
       if (child.name == "Bone"){
           // the code here is called 
           // for each child named Bone
       }
   }

In your code, you could also use the child found to search in its own children:

    if (hit.transform.name == "Bone"){
        target = true;
        var boneChild = hit.transform.Find("Bone");
        if (boneChild){
            // bone child found
        }
    } else {
        ...

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Edyvargas · Nov 07, 2011 at 12:11 AM 0

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I use the first method, Thank you very much aldonaletto!

All is the same, i only add one line to my code, and edit the name, this are the changes:

 bone = transform.Find("Crate/Crate [Layer1]/Bone"); //new line added, create a var name that holds the child object name.

 if (Physics.Raycast (ray, hit, distanceDetection)){

     if(hit.transform.name == bone){ //insted of use string name, use the variable with the name.

aldonaletto · Nov 07, 2011 at 12:30 AM 0

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The last line will not work, because bone is a Transform and hit.transform.name is a String. You can't compare Transform to String (transform.name), but you can compare Transforms:

 if (hit.transform == bone){

Edyvargas · Nov 07, 2011 at 12:53 AM 0

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You are right, its not a string, but works that way and dont with (hit.transform == bone) without the "name" at the end....i dont know why ¿?... UPDATE: the code isnt working properly, i must tune it some more..

aldonaletto · Nov 07, 2011 at 10:09 AM 0

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You could use:

   if (hit.transform.name == "Bone"){ // compare names

or

   if (hit.transform == bone){ // compare Transforms

Notice that you use the full path name to find some object deep in the hierarchy, but the transform.name property itself holds only the name - it's like files in the computer: the filename is always the same, no matter in which directory it is.
Another thing: maybe you're having problems because the object was not found due to some misspelled name or other reason; place a debug line after Find:

 bone = transform.Find(....);
 if (!bone) print("Bone not found");

Edyvargas · Nov 07, 2011 at 07:47 PM 0

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Ill try that and post the results later, thanks!.

Note: by the moment im using (hit.transform.tag == "Bone"), and put to the grandchild the tag name "Bone", that way the object its called always without any problem, but i want to do it without the need of create a new tag name if possible, post results later...

Answer 2

Answer by IMD · Jun 12, 2013 at 12:01 PM

Here's a little function I just cooked up that might come in handy..

  static public GameObject getChildGameObject(GameObject fromGameObject, string withName) {
         //Author: Isaac Dart, June-13.
         Transform[] ts = fromGameObject.transform.GetComponentsInChildren();
         foreach (Transform t in ts) if (t.gameObject.name == withName) return t.gameObject;
         return null;
     }

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FamerJoe · Jan 15, 2014 at 01:38 PM 0

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You need to add the class type to this line for this to work:

Transform[] ts = fromGameObject.transform.GetComponentsInChildren();

Pawl · Jul 18, 2014 at 11:32 PM 1

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 Transform[] ts = fromGameObject.transform.GetComponentsInChildren<Transform>(true);

Answer 3

Answer by vladibo · Nov 16, 2018 at 02:24 AM

         internal static Transform FindChildByRecursion(this Transform aParent, string aName)
         {
             if (aParent == null) return null;
             var result = aParent.Find(aName);
             if (result != null)
                 return result;
             foreach (Transform child in aParent)
             {
                 result = child.FindChildByRecursion(aName);
                 if (result != null)
                     return result;
             }
             return null;
         }

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Answer 4

Answer by anthoxico · Nov 15, 2018 at 05:55 PM

 List<GameObject>  childrens = new List<GameObject>();
 int count = 0;

 while (count < gameObject.transform.childCount)
 {
     childrens.Add(gameObject.transform.GetChild(count).gameObject);
     count++;
 }

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Answer 5

Answer by starrtennis · Nov 19, 2019 at 10:41 PM

UnityEngine.GameObject.Find("name") finds any gameobject by name. Just make your child have a unique name please! But remember: It's computationally intensive.

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How to find a Child Gameobject by name?

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