Transform vs Gameobject

Questions & Answers
1

I’m wondering what are some examples or use cases in which Transform would be better to use instead of GameObject or even when a Vector is better than a Transform. I have heard some people say I sometimes use GameObject when only Transform is necessary.

For Example : If I want to spawn my object in a location with a specific rotation would I cache my transform and rotation a a vector and a quaternion, a transform or a gameobject?

Apologies if sounds vague or generic.

2

Hopefully you understand the fundamental difference between GameObject and a Component like Transform. In most cases it’s better to use a Transform reference or even a reference to another component. That’s simply because the GameObject is just a container for components. It offers only little functionalities like getting / setting the layer or destroying the whole gameobject since you need a reference to the OameObject in this case.

The Transform component offers: the position, rotation, scale of the object in the scene, it’s position in the hierarchy (parent). If i need a general purpose field where i can assign some kind of gameobject i always use Transform. Since every GameObject must have a Transform it’s almost always the better choice. Also you can almost do the same things with a Transform you can with a GameObject. GetComponent and the “shortcut properties” are the same for GameObjects and Components.

I don’t fully understand your example. Vector3 and Quaternion are valuetypes while GameObject and Transform are reference types. So you can’t really compare those things since they behave very differently. I think a better description of your use-case would help :wink:

3

GameObjects and Transforms are very closely linked in Unity: every GameObject has a Transform component, and you can’t have a Transform without a GameObject.

This means that, in most cases, a reference to either will work, and which variable type you pick should depend on how you’re going to be manipulating it in scripting. For example:

  • If you’re mostly going to be
    performing transformations on the
    referenced variable through code, a
    Transform reference makes sense
    because you just have to call
    myTransformVar.position instead of
    myGameObjectVar.transform.position .

  • If you’re mostly going to be doing
    things like cloning or instantiating
    other objects from your variable, or
    setting its value by using a
    FindWithTag function, GameObject
    probably makes more sense. The
    Instantiate function requires a
    GameObject reference, and doing
    something like…

    myTransformVar = FindGameObjectWithTag("myTag").transform;

    …will throw an error if Unity is
    immediately trying to get the
    transform of a GameObject it can’t
    actually find (because that tag
    hasn’t been created or assigned).

BUT the good news is that if you have a reference to one of these (Transform or GameObject), you can quickly get a reference to other at any time in your script! Every Transform’s associated GameObject can be accessed with

myTransformVar.gameObject

and every GameObject’s transform can be accessed with

myGameObjectVar.transform

If I’m going to be using both a lot, I’ll sometimes create a GameObject variable and a Transform variable and store references to both in my script for quick code access.

4

What I don’t quite get is why Instantiate wants a transform for the parent (not a GameObject). Is there any good reason for that that I am missing?