Introduction to modding

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Introduction to modding

Creating a game is like writing a theater play: in both cases, you have stages, actors, scripts, and music. A level is built so that when the player performs certain actions or reaches certain locations on the stage, further events are set in motion according to the script. The player is told what to do through various textual instructions, cutscenes, and/or voice acting (more "scripts") and as he plays he interacts with AI-driven actors. Music will often play dynamically behind all this, changing along with the flow of events. Modifying, or "modding", a game can be simpler and easier because you might only be changing or creating some of the above elements.

Nevertheless, modding can be an intimidating field to get into. But if you take things one step at a time, you can learn a lot about how to make games; in fact, many game developers start out as modders. Like learning a new language, modding your first game is always the hardest, and then you learn the common points that languages/games share, and you can more easily pick up new ones. Additionally, there are lots of different ways for someone to mod; whether your talent is art, sound, modeling or design in general, there's something for you to do, and collaborating with others to divide the work according to your abilities can lead to a memorable, rewarding creative experience.

Now, our community does not have the polished modding tools of the big engines like Unreal (but we're getting better). Because of the DIY nature of our work here, it's recommended that you have a high tolerance for technical details. We do not yet have any modding solutions with a big red button that says "easy".

So, if you still want to learn about Oni modding, here's a first pro tip:

To create new bsl and xml files on Windows, make a new txt file and rename the suffix to bsl or xml. Check THIS page, it tells you how to display file extensions.

Introduction to the engine

Oni runs on an engine that was custom-written for the game and that could be built for both Windows and the Macintosh (later, PlayStation 2 support was added). At the time development started, Bungie did not yet have a true 3D engine, and Oni's lead coders intended their work to be reused in future Bungie titles, so they tried to make it well-engineered and portable. The engine consists of various "modules", sometimes with colorful names like Akira (environment), Motoko (graphics), and Totoro (animation). Unfortunately, the game was rushed to release during a change of ownership, and it was not possible for the developers to release any tools or information to aid the fans in modding.

Due the non-existence of modding tools at the time of Oni’s release, fans had to tame the wild jungle of raw game data and create modding tools on their own through reverse-engineering. It took over seven years to unlock most of the game's secrets –- and the work is still ongoing. Read the full story HERE. But to make a long story short, we can now mod almost all types of data effectively, meaning we can create entirely new levels with new characters, new scripts, new voice acting, and new music. Now we're turning our focus to making tools that are user-friendly so artists can work more freely.

Altogether, we have identified 124 types of resources in the game data, however Oni only uses about 88 of these types (often called "file types" on this wiki, and "tags" in many other game modding communities). It may sound intimidating at first, but many of the data types fold into each other, such that you only need to know a few file types well, and the rest are created for you. Depending on the kind of modding you want to do, you might be able to start modding with only a little knowledge of the engine.

Kinds of modding

Scripting

The easiest kind of modding is scripting. Scripts are written in the BungieFrameWork Scripting Language and stored as plain-text files with the suffix .bsl, so we often refer to scripts as "BSL mods". Scripts take a lifeless level and spawn characters in it (the AI-driven NPCs and Konoko), give the level a logical flow of events, make the AIs play certain roles, drive cutscenes, and alter the level's appearance.

Scripting is the easiest way to mod because you can work with existing game data, and only have to modify BSL files using a text editor. It's quick and easy to see the results of your work (just reload the level), and you have lots of accessible examples to learn from (14 levels' worth!). That being said, scripts constantly reference game resources in sometimes technical ways, so you will have to learn how certain data types work in order to script effectively.

Go HERE to start learning about scripting.

Binary modding

This is where those 88 data types come into play that we mentioned earlier. Broadly speaking, the kinds of data we're talking about are: level geometry (architecture, triggers, and furniture), characters (class data, models), text (diary, objectives, subtitles, etc.), music, voice-overs, and sound effects. However, new levels do not require all this data to be made from scratch. You might decide to re-use a level or some of its resources, or make a new level populated with existing characters, etc.

The game data is called "binary data" because it's made of raw 0s and 1s until our tools make it into something more modder-friendly. The basic process of modding game data involves breaking the level data (a .dat file supplemented by a .raw file and also a .sep file on the Mac) into its component resources (.oni files), then converting those resources into something editable. What that editable format is depends on the kind of data you're editing. It might be plain-text, XML, PNG, DAE, WAV, etc.

Thus, besides our community modding tools, the program(s) you need in order to mod will vary according to your modding task; you might need nothing more than a text editor, you might need a free bitmap editor, or you might need a full 3D modeling package. Thankfully, since Oni is graphically primitive, you won't need to know as much about modeling as with a modern game, and there are free modelers available (but not as good as the commercial ones). In any case, make sure you download the Anniversary Edition, which provides a modding framework and installs modding tools.

Go HERE to start learning about the binary data, HERE to learn about the user-friendly XML modding technique, or continue reading to learn a little more about specific types of binary modding so you know what you're getting yourself into.

Character models

Characters in Oni are built with a simple 19-part skeleton. Talk about ONCCs and related data here. Mention Mod Tool, Blender.

• tutorial: Importing character models TRBS
• tutorial: Adding spawnable characters to a level CHAR
• tutorial: Adding character classes ONCC

Character animations

An "appetizer screenshot".

Talk about OBANs and TRAMs here. Mention Mod Tool.

• • tutorial: tweak animation

You need to add some stuff to that file to make it actually work as an animation. In particular the animation type, from/to states and varient needs to be set.

For all I know this works with animations exported from Oni and modified in Softimage. If you come up with a completly new animation it should work as long as the skeleton is similar to the one used in Oni.

Textures

Mention Gimp, Paint.NET.

• tutorial: Modifying textures TXMP

Weapons

• tutorial: Importing_weapon_models

Levels

Talk about AKEVs and related data here. Mention Mod Tool, SketchUp.

• tutorial: AE:Authoring_custom_camera_animations

Sound and Music

• Instructions on importing sounds and links to conversion tools can be found HERE.

Need some inspiration?

Play some existing mods to get ideas (which you can install with the AE), or look at the pages below.

• Modding Brainstorms
• Review criticisms
• Animation ideas