EditorUtility.InstanceIDToObject  

static function InstanceIDToObject (instanceID : int) : Object

Description

Translates an instance ID to a reference to an object.

If the object is not loaded from disk, loads it from disk.

Editor Window to enter the instance ID and print the name of the object.

// Simple editor window that prints on the console the GameObject
// name given an ID.
// If no objec is found it prints an error.

class EditorUtilityInstanceIDToObject extends EditorWindow {

    var id : int;
    @MenuItem("Examples/ID To Name")
    static function Init() {
        var window = GetWindow(EditorUtilityInstanceIDToObject);
        window.position = Rect(0,0,160, 60);
        window.Show();
    }

    function OnGUI() {
        id = EditorGUILayout.IntField("Instance ID:",id);
        if(GUILayout.Button("Find Name")) {
            var obj = EditorUtility.InstanceIDToObject(id);
            if(!obj)
                Debug.LogError("No object could be found with instance id: " + id);
            else
                Debug.Log("Object's name: " + obj.name);
        }
    }
}