Beelim

Are you itching to insert teddy bears and crazy death robots into your game? or are you just peeved that BHG left a whole load of inconsistencies and ahistorical bull in your game? well then, this guide is meant for you!

Modding a unit in Rise of Nations looks more difficult than it really seems. To be honest, the only issue involved may be in creating the renders and the tedium in the coding required, but overall it is actually a very fast process, and sometimes rewarding as well.

HOW DOES THIS GUIDE WORK?

This guide tries to go step by step in designing a model from scratch, from the creating of the graphics required for a new unit all the way to getting it to work in the game. We will first explain how graphics are created, and then go on to inserting the model into the game itself.

HOW DO GRAPHICS IN RISE OF NATIONS WORK?

In Rise of Nations, units consist of two elements - the graphic files which allow a unit to appear and be animated in the game world, as well as coding which allows the unit to perform its functions in the game.

WHAT FILES GOVERN A UNIT'S APPEARANCE?

This is determined by the following:
- a .bh3 model. This is the model for the sprite as it appears in your game, and will be stored in your /art folder;
- .bha files, which governs unit animation, ie how the unit moves and so forth, which goes into the /art folder too;
- a .tga file, which if not properly inserted causes the unit to appear white. This also goes into the same folder as above; and
- entries in the unit_graphics.xml file under your/data folder.

BUT HOW ON EARTH DO I GET IT TO WORK?

There are several files which govern how a unit functions:
- unitrules.xml, under your /data folder, will govern a unit's attributes, ie attack, movement speed, hitpoints, as well as graphics; and
- craftrules.xml will govern the abilities of your unit.

Of these, however, we must pay utmost attention when modifying any xml files in Rise of Nations - faulty coding at the least will leave units inoperable, and at worst crash your entire game. For this reason we strongly discourage overwriting any source files in /data or /art unless it is necessary.

HOW MANY CUSTOM UNITS CAN I INSERT INTO RISE OF NATIONS?

Sadly, the answer is none, because in reality the number of units is determined by the number of entries for each unit in Rise of Nations in the unitrules.xml file (for convenience, we will call each area where you can insert data for a new unit as a "slot"). Each slot is demarcated by the tagging ...., with the statistics of the unit (ie name, type, tactical parameters, etc) located within this tag. You can only create new units by "cannibalising" existing slots.

ENOUGH BABBLING! JUST SHOW ME HOW TO DO IT!

Let's use an example from Rise of Kings.

Suppose that I want to insert a new unit that I want to call "Bedouin Retinue", a cavalry unit which throws spears and is represented by two different sprites. How do I go about this? the answer is simple:

Graphics

The first thing I do is to get out the graphics for two different sprites. I procure two .bh3 files, as well as two .tga files. We shall call one (with a harness for our cavalry unit) "towelhead.bh3" and the other one as "sheikh-stripy.bh3"

The .bh3 and .bha files for Rise of Nations can only be created if you have 3ds Max 5.1 and the Big Huge Exporter plugin produced by BHG. We will not cover this, there are many tutorials elsewhere on how to create your own 3d models using this program.

Meanwhile, on to sprites. You must be asking, why do we need to create two sets of .tga files if we are just creating only one unit? this is because although I am only creating one unit, I want this unit to have a varied appearance, hence the need for two .bh3 files - one for each sprite. The bh3 files however are not enough on their own, so I must also have .tga files which form the "skin" of the unit.

In this screenshot, you can see what the .tga file for "sheikh-stripy.bh3" looks like when opened up in GIMP2.8. Remember that to create unit colour areas, you need to render parts of the model semi-transparent.

Rise of Nations when in operation "wraps" the texture of the tga around the model as determined by the bh3 file. If we opened up the unit model file in 3ds Max and then used the tga file as its skin, this is what it would look like:

With these files ready, I will now put the bh3 files into the /art folder of my Thrones and Patriots/mods/Rise of Kings 1.0/art folder. We will save one tga as "sheikh-stripy.tga" and the other as "super-sheikh" as shown below:

Coding the unit's appearance

Next comes the fun part - unit appearance. Unlike unit slots in the unitrules.xml folder, you can have as many entries as you want for your sprite graphics, so I will now create a new entry in my unit_graphics.xml file under mods/Rise of Kings 1.0/data folder.

At this stage, you need to be careful when inserting the new graphics. Always ensure that the coding here is inserted correctly.

The anim_graphics file (TBC)
The unit_graphics file (TBC)
The unitrules file (TBC)