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Why is Prefab declared as type Transform?
I am looking through some code for a simple game where eggs are dropped into a basket. The script that spawns the eggs uses a prefab and thus creates them with the Instantiate method. However, what confuses me is what is passed into the first parameter of the Instantiate method.
public Transform eggPrefab;
Instantiate(eggPrefab, spawnPos, quat);
Why is the eggPrefab declared as a type Transform when it is in fact a GameObject? Isn't a Transform object just something that can be contained inside of the eggPrefab?
Thanks,
I use GameObject and it works fine in this example I don't think it matters.
Answer by stillmotion · Oct 12, 2018 at 07:41 PM
Transform is not just a representation of position, scale and rotation in the scene, but also a Component subclass that is attached to your prefab game object. The documentation for Instantiate
describes:
If you are cloning a Component then the GameObject it is attached to will also be cloned, again with an optional position and rotation.
Thus your prefab is referenced in the script by its Transform component alone. Calling Instantiate
with this reference will clone the Transform AND the prefab game object.
Right, also Instantiate will return the instantiated component. This is quite useful because you barely need anything from the GameObject class. You usually store a reference to a more useful component and use that for instantiate. For example if the prefab contains a custom script of yours you can use a variable of your script class and drag the prefab onto that. When you instantiate your prefab you directly get back the reference to the script on the instantiated object.
Upvoted because you actually picked a better explanation from the documentation and actually highlight the important thing.
Answer by CSE_DHancock · Jun 17, 2013 at 05:53 PM
From the Unity Documentation:
This function preserves the position and rotation of the cloned object. This is essentially the same as using duplicate command (cmd-d) in Unity. If the object is a Component or a GameObject then entire game object including all components will be cloned. If the game object has a transform all children are cloned as well. All game objects are activated after cloning them.
You can find the full article with more information here.
Essentially, it can be either or. Holding onto the transform can shortcut the need to grab it manually if you need position information and you can clone it as its a component on the game object, which as the above states, will clone the entire game object.