GetComponentInParent... Is this a bug or what exactly is wrong with this.

Unity Engine
1

This gives me a Vector3:

hitone[i].collider.GetComponentInParent<Rigidbody2D>().transform.position

While this gives me a Vector 2: (What I want)

hitone[i].collider.GetComponentInParent<Rigidbody2D>().position

This gives me .this object name rather than the parent:

hitone[i].collider.GetComponentInParent<Transform>().name

While this gives me the name of the parent: (What I want)

hitone[i].collider.GetComponentInParent<Rigidbody2D>().name

I did waste A GOOD AMOUNT OF TIME dealing with these things, so I would like to know what exactly is wrong with the first approaches :smile:

2

The first two items are normal behaviour. You can cast a Vector3 to a Vector2, unity will simply drop the z component. Transform.position is a Vector3.

Not sure what’s happening in the second example.

Note that Collider2D.attachedRigidbody will also give you what you want.

3

Unitys transform component is the same for 2D and 3D objects, so every object has a vector3 as its transform position.
for the second one, i’m not sure but i think one of unity’s ways to access child-transforms is ‘Transform in transform’ (like foreach (Transform t in transform) {t.doSomething();} ), so you’re actually re-accessing the child.

4

GetComponentInParent returns the component attached to the given GameObject or any of its parents. Every GameObject has a transform so in that context you’ll always get back the transform of the GameObject you’re looking at. I would imagine in your second case the parent has a Rigidbody2D component but the GameObject with the collider does not.

In your first example - transform.position is always a Vector3 regardless of how you get to it. Rigidbody2D.position is a Vector2 because it only deals in 2 dimensions.

So, no. Not a bug :slight_smile:

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5

I always thought parent was a reference to the hierarchy, not “closest object above with this game Component”.
For some reason, suddenly, I have many things to fix. :smile:

Thanks for the answers!

6

There is your answer. I personally never use GetComponentInParent. As a general rule my GameObjects are not allowed to know about their parents, except in a very general SendMessageUpwards or ExecuteEvents.ExecuteHeirarchy kind of way.

One way dependency is much easier to manage. (ie parents can know about their children, but children cannot know about their parents).

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7

The name is certainly a bit misleading. The most straight-forward way to do what you want would be this

transform.parent.GetComponentInParent<Component>();

While, of course, checking that your transform actually has a parent in the first place.

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