I have owned Civilization IV for more than five years, but in all of that time I never pursued modification of the rules in any form. I knew that other gamers had undertook the challenge and created a number of fine Mods to the game.
I have been playing the Thomas’ War Mod for more than a year and absolutely love it. But even with this fine Mod, my friends and I wanted to do more. We loved playing the early part of the game, and always felt that it lacked allot of options in the way of alternate technological developments, different units, and options.
The other day my cousin suggested that I create my own mod for the game. I looked at him and scoffed. I have never been very good at programming and looked at the massive XML files with utter horror. But he kept pressing and telling me about what we could accomplish.
So I undertook a limited modification to the Thomas’ War Mod, which quickly grew into massive overhaul to the technological tree, the units, the buildings, and even new and varied civilizations.
Civilization IV allows you to modify the rules in three distinct levels of complexity. The first and easiest way, is to go into the MAPS/SAVE folder and make simple changes to the maps. Given some experimentation, you can change the tiles on the maps and add or subtract various animals, units, and starting technologies. To edit any of the variables in the map or XML, you need to make adjustments opening key files and copy and paste blocks of code or change values that already exist.
The next step up is the modification of the XML files that can be found in the Mods directory under XML and then the appropriate sub-directory that you want to modify, such as Technologies or Units. I open these XML files with Word Pad, but there are many other programs you can use. At first it appears very daunting but I suggest starting small and changing a value here and there. Always BACKUP all your XML files first because it is very easy to screw something up and nothing is worse than destroying a fine game like Civ. Some of the biggest problems I encountered with the XML is that you must be very careful modifying the list; even the smallest change can cause the program to crash. Make sure you watch spelling and copy whole blocks of code — if you accidentally delete a line in the XML, it won’t run. Consistency is very important throughout.
Ultimately, if you are patient enough you can modify the core program itself using the Python programming language. Also you can develop further models with any sort of Photoshop like programs.
I am halfway through step two. At first I was so timid to adjust the XML files but over the course of a couple of weeks I am confident enough to change the entire tech tree and adding new units (the art already provided from innumerable web sites).
If there is interest to those that come and read this, I can provide short tutorials on how to add tech, units, and even buildings. If you would like to see more, please comment.