How do I use SendMessage to send a Vector3?

Questions & Answers
1

So I need to edit a Vector 3 from one script but it is in another script, I tried using SendMessage but I dont know how to.

2

Are you trying to avoid using public access? You may simply expose that Vec3 to other scripts either by setting the field to public or by encapsulating it in a property and exposing it that way. Limiting access is commendable, however. If you do prefer to use SendMessage, it does allow you to send a single argument. The Message handler will need to be declared with with an argument of the type you send:

using UnityEngine;
public class ClassA : MonoBehaviour {
    private Vector3 myVector3;

    private void HandleMessage(Vector3 value) {
        myVector3 = value;
    }
}

using UnityEngine;
public class ClassB : MonoBehaviour {
    void Start() {
        FindObjectOfType<ClassA>().SendMessage("HandleMessage", new Vector3(1, 2, 3));
    }
}