Assigning members of transform.position (C#)

Scripting C# & .NET
1

It seems like I cannot assign members (x,y,z) of the gameObject.transform.position property using C#, it gives this exception:

error CS1612: Cannot modify the return value of `UnityEngine.Transform.position' because it is not a variable

However, the Unity docs have an example for Mathf.Clamp() method that does exactly what I need:

transform.position.x = Mathf.Clamp(transform.position.x, 0f, 10f);

Is it a known issue, or am I missing something?

I’d like to perform the direct assignment to clamp the position and avoid creating a new Vector3 object in every Update().

Thanks!

2

Vector3 is a struct, which is passed by value and not by reference. In C# you must do:

Vector3 position = transform.position;
position.x = Mathf.Clamp(position.x, 0f, 10f);
transform.position = position;

The documentation uses JavaScript, will allows this through compiler magic.

Structs are created on the stack and not the heap, which doesn’t allocate anything. Don’t worry about performance.

3

Thank you, Matthew
I did not know Vector3 is a struct, that explains it.

4

Alternately, you could do this:

transform.position = new Vector3(Mathf.Clamp(position.x, 0f, 10f), transform.position.y, transform.position.z);
5

This was helpful for me, but I was able to clean it up a bit:

Vector3 position = transform.position;
position.x = 2.0f;
transform.position = position;
6

I’ve found that extension functions can be useful if you end up doing this a lot.

7

Wow thank you!! haha i hace tried to figure this out for hours! haha and it was pretty easy xD

But thanks! :slight_smile: i can go further now.

My code:

Thanks :smile:
Justin Bieshaar - Game Development Student ,Media College Amsterdam