Unity3D - How to randomly instantiate random sized cubes without overlap? - random

Question

I'm trying to randomly instantiate some random sized cubes in a grid but whenever I randomly instantiate said cubes, they tend to overlap. Can someone point me in the right direction to prevent them from overlapping? I tried asking the unity forums and so far, no one has bothered to respond.
Edit: In response, I've added some of the code I'm trying to use. For the most part, I have no clue on how to prevent the cubes from overlapping. This is in C#. Yes I realize I'm not the best coder in the world, that's why I'm stuck on this problem for over 3 weeks.
void InstantiateItems(GameObject[] ItemArray, int Increment)
{
// Select a random treasure from the appropriate treasure array
// TreasureSelect is a public int, ItemArray refers to one of three possible different sized arrays passed into this method
// By calling the random.range and using the passed array's length, you can select a random item from that particular array
TreasureSelect = Random.Range(0, ItemArray.Length);
// Store a random x and y position using info from the GridArray
// Stored Cell is a vector3, GridArray is a 2D array that contains x and y coordinates of a grid's width and height
// The goal is to store the position of a random dirt cube's position from the grid and use that as the position to instantiate a treasure cube item
StoredCell = GridArray[Random.Range(0, GridWidth), Random.Range(0, GridHeight)].transform.position;
// Get the stored x and y offset variables from the treasure cube item's script
// The offset variables are always half of the treasure cube object's scaled x and y values
float incomingX = ItemArray[TreasureSelect].GetComponent<Treasure>().offsetX;
float incomingY = ItemArray[TreasureSelect].GetComponent<Treasure>().offsetY;
// check to see if the object will spawn partially outside of the dirt field
// If the randomly generated x value is greater than the grid's width minus the treasure object script's x value, then adjust the randomly generated x value
if (StoredCell.x >= (float)GridWidth - incomingX)
{
// If determined that it will spawn partially off field, adjust the value
newX = (float)StoredCell.x - incomingX;
// Check to see if the number is odd or not
// If the number is odd, then it will need to have an additional .5 added to make the treasure object line up with the dirt cubes above it (since the pivot point is at the center of the unity cube object)
if(newX % 2 == 1)
{
newX += incomingX;
}
}
else if (StoredCell.x < incomingX)
{
newX = (float)StoredCell.x + incomingX;
if (newX % 2 == 1)
{
newX -= incomingX;
}
}
else
{
newX = StoredCell.x;
if (newX % 2 == 1)
{
newX += incomingX;
}
}
// Now we use the y value instead of the x value and use the grid's height instead of the width
if (StoredCell.y >= (float)GridHeight - incomingY)
{
newY = (float)StoredCell.y - incomingY;
if (newY % 2 == 1)
{
newY += incomingY;
}
}
else if (StoredCell.y < incomingY)
{
newY = (float)StoredCell.y + incomingY;
if (newY % 2 == 1)
{
newY -= incomingY;
}
}
else
{
newY = StoredCell.y;
if (newY % 2 == 1)
{
newY += incomingY;
}
}
// Instantiate the object with a new vector3 using the spawn point object's rotation
Instantiate(ItemArray[TreasureSelect], new Vector3(newX, newY, OffSetZ), ItemArray[TreasureSelect].transform.rotation);
ItemArray[TreasureSelect].transform.position = StoredCell;
}