How to Position an Object Separately from Randomized Objects in Unity?

Question

In my 2D game I have randomized objects which are spawned as 4 to 5 clones each time I run the game. My problem is that I also have a different object that I want to spawn as 1 clone, and position it to appear after the last clone of the randomized objects I have in my game.

The objects randomization works perfectly in my game, I just need to separate that from the object that I want it to be spawned independently and after the last clone of the randomized objects.

This is the code I am using with 1 line of attempt to spawn the independent object: (The code was taken from this tutorial )

 using UnityEngine;
    using System;
    using System.Collections.Generic;       //Allows us to use Lists.
    using Random = UnityEngine.Random;      //Tells Random to use the Unity Engine random number generator.

    namespace Completed

    {

        public class BoardManager : MonoBehaviour
        {

            // Using Serializable allows us to embed a class with sub properties in the inspector.
            [Serializable]
            public class Count
            {
                public int minimum;             //Minimum value for our Count class.
                public int maximum;             //Maximum value for our Count class.


                //Assignment constructor.
                public Count (int min, int max)
                {
                    minimum = min;
                    maximum = max;
                }
            }


            public int columns = 7;                                         //Number of columns in our game board.
            public Count random1Count = new Count (1, 2);                       //Lower and upper limit for our random number of objects
            public Count random2Count = new Count (1, 1);
            public Count random3Count = new Count (1, 1);
            public Count random4Count = new Count (1, 1);

            public GameObject[] randomObject1;                                  //Array of objects prefabs.
            public GameObject[] randomObject2;
            public GameObject[] randomObject3;
            public GameObject[] randomObject4;

            public GameObject obj; // the independent object declaration

            private List <Vector3> gridPositions = new List <Vector3> ();   //A list of possible locations to place objects.


            //Clears our list gridPositions and prepares it to generate a new board.
            void InitialiseList ()
            {
                //Clear our list gridPositions.
                gridPositions.Clear ();

                //Loop through x axis (columns).
                for(int x = 2; x < columns; x++)
                {


                    //At each index add a new Vector3 to our list with the x and y coordinates of that position.
                    gridPositions.Add (new Vector3(x, 0.3f, 0f));

                    Instantiate(obj); // my attempt to instantiate the separate object
                    Debug.Log(obj.transform.position.x); // my attempt to track the position of the separate object
                }

            }


            //RandomPosition returns a random position from our list gridPositions.
            Vector3 RandomPosition ()
            {
                //Declare an integer randomIndex, set it's value to a random number between 0 and the count of items in our List gridPositions.
                int randomIndex = Random.Range (0, gridPositions.Count);

                //Declare a variable of type Vector3 called randomPosition, set it's value to the entry at randomIndex from our List gridPositions.
                Vector3 randomPosition = gridPositions[randomIndex];


                //Remove the entry at randomIndex from the list so that it can't be re-used.
                gridPositions.RemoveAt (randomIndex);


                //Return the randomly selected Vector3 position.
                return randomPosition;

            }


            //LayoutObjectAtRandom accepts an array of game objects to choose from along with a minimum and maximum range for the number of objects to create.
            void LayoutObjectAtRandom (GameObject[] tileArray, int minimum, int maximum)
            {
                //Choose a random number of objects to instantiate within the minimum and maximum limits
                int objectCount = Random.Range (minimum, maximum+1);

                //Instantiate objects until the randomly chosen limit objectCount is reached
                for(int i = 0; i < objectCount; i++)
                {

                    //Choose a position for randomPosition by getting a random position from our list of available Vector3s stored in gridPosition
                    Vector3 randomPosition = RandomPosition();




                    //Choose a random tile from tileArray and assign it to tileChoice
                    GameObject tileChoice = tileArray[Random.Range (0, tileArray.Length)];


                    //Instantiate tileChoice at the position returned by RandomPosition with no change in rotation
                    Instantiate(tileChoice, randomPosition, Quaternion.identity);

                }

            }


            //SetupScene initializes our level and calls the previous functions to lay out the game board
            public void SetupScene (int level)
            {

                //Reset our list of gridpositions.
                InitialiseList ();

                //Instantiate a random number of objects based on minimum and maximum, at randomized positions.
                LayoutObjectAtRandom (randomObject1, random1Count.minimum, random1Count.maximum);
                LayoutObjectAtRandom (randomObject2, random2Count.minimum, random2Count.maximum);
                LayoutObjectAtRandom (randomObject3, random3Count.minimum, random3Count.maximum);
                LayoutObjectAtRandom (randomObject4, random4Count.minimum, random4Count.maximum);


            }
        }
    }

Answer 1

When you instantiate your final GameObject, you're not giving it a position. As I understand it you want to position it in the same place as your last randomly positioned GameObject, but offset in the x axis. To do this you'll need the Vector3 that contains the position of the last randomly spawned GameObject, I'll call this lastRandomPos . I assume you know how to get this value, if not leave a comment and I'll include it in my answer. Then you can pass the position when instantiating your final GameObject:

var objPos = lastRandomPos;
objPos.x = objPos.x + <however much you want to offset in x>;
Instantiate(obj, objPos, Quaternion.identity);

EDIT: The easiest way for you to get the position of the last random object is to just set a class-level variable every time you Instantiate an object in LayoutObjectAtRandom . Declare it in the class scope, for example underneath your declaration of gridPositions :

private List <Vector3> gridPositions = new List <Vector3> ();   //A list of possible locations to place objects.
private Vector3 lastRandomPos;

Then when you Instantiate a random object you can set this variable to keep track of where it was spawned:

Instantiate(tileChoice, randomPosition, Quaternion.identity);
lastRandomPos = randomPosition;