This is my first question on stackoverflow, and I am earnestly open to feedback on how/where/when to ask better questions and how to contribute to stackoverflow better.

**Background:**  

My ultimate goal is to graph projected equipment usage by date at various test labs. 

I have identical equipment in use at several labs, and I'm creating a sheet that will show me a future projection of equipment usage at each lab.

**What I'm Starting With:**  

I have an Excel document with several worksheets, each containing information on what equipment will be used at which test house during what period of time.

**My Goal:**  

To create a graph of equipment usage for each test lab. The graph will show how many of each piece of equipment are in use for a given date. My intention is to have a chart series for each type of equipment with Date as the X-axis and the number of pieces of that equipment in use on the Y-axis.

**What I've Done So Far:**  

I have written code that loops through all my information sheets and creates a vba collection of every unique test lab name and a separate vba collection of every unique piece of equipment I want to track. This code also finds the first date and last date any piece of equipment is used.

**Help Request:**  

Because I essentially have three "dimensions" - Test Lab, Piece of Equipment, and Equipment Use Date - I had planned to use a 3D array to aggregate all my data and provide the source for my usage graphs. This array would have equipment as one dimension, date as the second, and test lab as the third.

However, as I've considered this implementation, it seems rather clumsy. It will hold all my data, but, as far as I can see, I can't refer to the elements of the array by keys or labels. I would have to create separate 2D arrays to hold index labels for each dimension of the 3D array.

*Is there a 3D data structure in Excel VBA that supports index keys for each dimension?*

**Failed Searches and Attempts:**  

I first tried to create a unique array to hold equipment and usage date, each array named for a unique test lab. I learned from this post that I am not able to dynamically create and name an undefined number of new arrays within a sub: [Naming an array using a variable](https://stackoverflow.com/questions/27994108/naming-an-array-using-a-variable).

I then looked into whether I could use the collections I had already created to somehow function as labels for the array indices, but it seems that I'm not able to find the collection index by the key. I would have to loop through the collection to find the index every time I want to reference an element in the 3D array: [Retrieve the index of an object stored in a collection using its key (VBA)](https://stackoverflow.com/questions/28985579/retrieve-the-index-of-an-object-stored-in-a-collection-using-its-key-vba).