2DA or not 2DA – Overriding 2DA files

The subject of 2DA files has come up a lot recently.  What are they? How do you change them? How do you compile them?  In this tutorial we’ll take a look at how to work with 2DA files, and how to override them in a proper manner to introduce custom items and behavior to Dragon Age.

What is a 2DA File?

At its core, a 2da file is nothing more than a spreadhseet.  In fact 2DA stands for “2 dimensional array”.  A simple sheet of rows and columns.  Looking at an even more basic level, a 2DA is nothing more than a way to format data in the game.  A list of items for example and all thier related stats, works perfectly as a spreadsheet.

2DA files are used to define most, if not all, of the hard data in the game.  And as a bonus to modders, you have the ability to access and modify these 2DA files.

In its raw, uncompiled form, a 2DA is stored as a simple .xls file.  An Excel spreadsheet.  You can open them up and edit them in Microsoft Excel, OpenOfiice, or any other spreadsheet program that supports Microsoft Excel files.  In order for those spreadsheets to be used by the game, they are the compiled into a binary file with the extension .GDA

Overriding a 2DA File

So what if you want to create new data that is stored in these files, or you want to change existing data?  You could, in theory, simply modify the appropriate .xls file with the new data, then compile it, but this is actually the wrong way to go about it.  See, if you do this, then the game is patchedin the future with a new version of that file, your mod will possibly break, or you could cause problems with the game’s patching, or any one of many other issues.  This is something to keep in mind.  Changing base game files is usually a bad thing.  Avoid it whenever you can.

In this case, Bioware has given us a way of overriding these files without replacing the actual game files.  They call it M2DA’s, or Mutliple two dimensional arrays.  A really fancy way of saying, they can be used to extend or override base files.  Let’s take a look at how this works.

First, just to help illustrate, we’re going to work with a made up example.  This isn’t a valid 2da file, as its paired down for simplicity.

Let’s say the game has an .xls spreadsheet with items in it.  It might look something like this:

Here we can see a few items defined, and thier stats.  Let’s say this file is “items.xls”.  Now what we want to do is add a new item to the game.  We want to add a Longbow.  Now we could open up this file, items.xls, and add a new row for the longbow, with an ID of 5, but that would be the wrong way to do it.  Instead we’ll create a NEW file, let’s call it “items_bows.xls”.  And in here we will define our bow, but we’ll make sure to use an ID of 5, so it doesn’t interfere with the ones listed in the base file.

Now we have created a new file, with our new item.  We have, in essence, created an M2DA file.  But how does our data now get combined with the game’s data?  Its all in the file name.  Remember how the game’s file was called “items.xls” and we called ours “items_bows.xls”?  Notice that they both start with the same filename “items”.  This is the key.  When the game loads in the items, it will load in every 2da that starts with “items”, which means it will read it its own base file, and see definitions for 3 items, ID numbers 2,3, and 4, and then it will read in our file items_bows, and see another definition for an item with an ID of 5.  It will then combine both into a final table for the game’s use.

The two key points to making this work is the filename and the ID.  The proper filenames allow the game to merge the tables, and the proper IDs allow us to add new items, or if we used an existing ID we can replace or override the base data.  For example we could make a file “items_new_swords.xls”

This file, when combined with our previous two, would create yet another new item, a shortsword, ID 6, but it would also override the base longsword with new data, since it re-uses the same ID of 2.  Now let’s start looking at a real world example, with proper 2DA formatting.

A real 2DA is slightly more complicated, but not by much.  Let’s take a look at an actual 2DA.  This is from 2DA_base.xls

 As you can see, it isn’t much different.  First off, ignore the colors and formatting.  Bioware has done this in a lot of files, but it is only cosmetic and doesn’t affect the 2DA.  Let’s dissect this.

The first two rows in a 2da are always the same.  Row 1 contains the column names, with ID always being the first.  The rest will depend on the data in the 2DA.  Row 2 indicates the “datatype” of each column.  In the example above, row 2 tells us that ID is an integer, Label is a string, etc.

The actual data starts on row 3.  Each row must has a unique ID, and the IDs must be in sequential order, though you can skip IDs.

Earlier we said that the game knows which 2DA files to combine based on the file name, but how do you know what filenames to use?  This file that we’re looking at, 2DA_base.xls has the answer.  Column C in this worksheet gives us this information.  For example, lets look at Items.  We can see here that the file that defines items will start with “BITM_”.  Any M2DA’s you make to override items would need to have that same prefix.

Compiling 2DA Files

Now that we know how to use 2DA files, and create our own, we need to know how to compile those .xls files into the game’s .gda format.  This is very easy.  In order to compile these files we need to use a simple commandline utility that comes with the toolset, called ExcelProcessor.exe which you can find in:

Dragon Age\tools\ResourceBuild\Processors

Now there are a few different ways to use this tool, but for right now i’m going to just cover the simplest.  What you want to do is decide on some directory that you are going to use for saving your .xls files.  It doesn’t matter where that is, so its up to you.  Copy the ExcelProcessor.exe file to that location.  Then whenever you want to compile an .xls file, all you have to do is open the directory in Windows Explorer, then drag and drop the .xls file onto ExcelProcessor.exe and the program will take your .xls and compile it, placingthe compiled.gda into that same directory.

Where to Put the Compiled 2DA Files

Once you have your compiled files, you need to place them in the proper location for the game to use them.  This is an area that is still a bit grey, so I want to say right away that my information may be wrong or incomplete.  I’ll update this once we’ve all narrowed it down a bit more.  Righ tnow i’ve just been copying them into pretty much every override directory until it works 🙂