I was recently sparked by a question on the Fextralife forums of “How do modders do it?” when it comes to creating mods for video games, and not the kinds of modifications that hack and cheat, but the vibrant mods that games like Fallout 4, The Witcher 3 and Dragon Age: Inquisition receive. These types of mods have spawned thriving communities and their actions are increasingly being supported by the game developers themselves. As there is growing interest in the activity, I decided to put together a little guide and basic information tutorial on modding and how modders do their thing.

What is Modding?

“Modding” is short for “player made modification of a game file(s).”

Basic Modding Subgroups

• Models: also called ‘meshes’ these are the shapes of the items you see in game from characters, npcs, hair, trees, animals, boxes, etc. From this point on all solid objects will be referred to mesh or meshes.
• Textures: these are the graphics applied to the meshes
• Scripts: tells the game engine how to display the information above
• Effects: these are misc movement models, such as fireballs, waterfalls, etc, to create the illusion of movement in game

Meshes

A mesh is a specific item that is displayed in game that has two functions: static or moveable. A static item is a box or a tree or even a mountain, but a moveable is a character or animal.  In order for meshes to “feel” solid in game they are given what is called a “collision” box. This “box” can be any shape, but the point is to  make sure there is a contact with the environment to feel realistic. If you ever wonder why you walk through a person at times it is because the model does not have a collision box, or it is too small. In some video games we hear the term “hit box” which is really just a term for “collision.” Some models require bigger boxes, so the bigger they are, the more area there is to connect with.

Textures

Textures are your basic graphic, it shows your eyeball what you should see and what colour. Within the textures are several subgroups.

• Diffuse map: This diffuse map are the bright R/G/B (red green blue) colours you see.
• Normal map: this is a map that is hidden under the Diffiuse map; it tells the game where to send shadows. A graphic without a normal  map is flat
• Mask: A mask defines which surface should be affected by which section of a material. These are either greyscale or a single “channel” such as Red, Green, Blue or Alpha. Masks are used often for character creators to give different skin and hair colours.
• Emissive Mask: these are masks used for lights on armour, such as Mass Effect. Think of it like a little glow bug inside the texture paths. Because, really, that is what they do- glow!
• Alpha: Alphas are part of textures used to define an area. Say you have a piece of armour but you hate the belt on it. You can open up the texture file and under the alpha properties colour over the area you want to be invisible, save it and in game that belt is “gone.” The model is still there, but not visible to the eye.

Scripts

Different games uses different scripts, which are lines of code that execute a command. Skyrim, a very mod friendly game, uses Payrus. The Dragon Age Toolset uses Python. The meatier codes for the engine are generally a variation of those scripts that modders use and C++. Depending on which game you are modding depends on what script you use. There are hundreds of tutorials out there for people to use.

Effects

Also called FX or VFX, these are what make a fireball explode or a iceball freeze. They are usually moving bits of textures that are placed inside the game to give a realistic feel.

Modeling Programs

Next we will discuss modeling programs and good choices to look for.

• Max3DS: The bread and butter of 3D modeling. Max3DS has powerful tools and many plug-ins to work with almost every game engine.
• Blender: Open Source supplement for Max3DS comes with a large number of plug-ins and user generated help info and scripts.
• Milkshape: Used for Half-Life, Blockland, the Sims and Rock Raiders, is also used for other sand box games

Which Program Should I Use?

Pick one and stick with it. If you are not modeling for Milkshape specific games, download Max3DS or Blender. Whichever one you choose it is not wise to switch. The main reason for this is that Max3DS and Blender have different controls and short cuts. Once you get used to one, switching to the other might get confusing. Depending on the game you want to modify, look at the tutorials in place and check to see which one has the scripts and plug-ins you need.

Limitations

Many 3D modeling programs do not have baked-in collision boxes or moving pieces. Basic meshes are usually imported to a second program for that, such as Nifskope for Skyrim and Fallout. Before beginning any modding project make sure you have the other programs necessary.

Miscellaneous

• Z-Brush: Z-Brush is an amazing tool for creating things like hair. While it has a free 45 day trial, the cost of the project is about $500 USD. It is mostly used by professionals, but if you want to try your hand at making a hair mesh, read everything you can before downloading the free trial.
• Material Libraries: Some programs require Material Libraries before exporting. Many of these libraries come at a cost, some are free. Depending on the engine you are modding, most materials are applied outside of the 3D modeling program.

Textures

Next, we will discuss textures and all of their glorious nuances. There are 2 primary programs for texture work and they are as follows:

• Photoshop
• Gimp

So which to use? If you have Photoshop already, that works. If you are just starting you will want to download Gimp unless you feel like paying for a Photoshop license. Photoshop is a tool for professionals and Gimp is for everything else. Many tutorials for one can be applied to the other, although shortcuts will be different so expect a learning curve.

UV Maps

A UV map is how  a game projects a 2D image onto a 3 modeling surface. Look at this example:

The Diffuse texture is just a flat 2D image of the world. When added to the 3D sphere model it looks like a real globe.

That is the image file of a man’s head for Mass Effect 3. The image gets wrapped around the head model.

Wait!? BUT HOW?

Here is a picture of one of the cupboards I did for Skyrim

See how the checkers all look nice and even? On left hand side you can see how the image will fit on the cupboard. The green lines are the seams and shows where the lines will meet up.

You can also see in this picture how armour will fit onto the body once it is imported into the game.

Most programs have built in UV mapping. In Max3DS 2017 it almost 100% automated. There is very little to do than maybe  moving a piece or two around. Whatever game you are modding, there should be a tutorial. Texture modding a game is 1% program and 99% testing. Always make backups and you will be fine.

DDS

Most textures for games are saved in a DDS format. NVidia has a DDS tools. This is installed with your Photoshop or Gimp so you can view and manipulate the file. REMEMBER: You should always select “MIPS” when exporting unless otherwise stated in a tutorial. MIPS are used by the game engine for when an object is resized. Failure to do this will result in…well, shenangians. This tool also allows you to export Normal Maps.

This primer now concludes the entries on Modding 101. Beyond specifics, this should jump start your knowledge for trying it our yourself. Since every game has their own unique bits and pieces it is a good idea to consult those guides for more of the idiosyncrasies after consulting this guide. Now get out there and have some fun in the wonderful world of modding!

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