Tim Cain on how to write design documents and why systems should always support game's setting and story

Fallout co-creator Tim Cain has detailed the process of writing design documents and how to avoid situations where people are making different games despite working on the same team. Here are some professional tips from one of the most recognized RPG developers.

How to write design documents, or the concept of three S's — tips from Fallout co-creator Tim Cain

In April, Cain started a YouTube channel where he regularly shares stories about games he has worked on and discusses various gamedev topics. One of the recent videos is dedicated to design documents.

Cain always writes three documents in this very particular order:

Setting — it defines the space in which the game will take place;
Story — a very high-level description of what every player will experience, which will also help to find the main story quests;
Systems — game mechanics should support the things described in the first two documents because this is the only way to make them good and connected to the setting and story.

“They’re not only very different documents, but they’re intended for different people and they’re written differently,” Cain said. He also noted that he goes through this process when creating the original IP from scratch, but this approach can also work for other games as well.

Setting document

Cain tries to describe the setting in a sentence or two because this document is one of the first things that a publisher or ‌investor will see. So it should be more like an elevator pitch.
The setting should grab people’s attention and be ‌easy to create stories and quests for. Cain cited titles made by Troika Games, which involved a lot of player agency and provided enough space for different actions and behaviors.

Most of the settings I've ever made could be described as, 'Here's a thing that's very easy to explain, oh, but there's a twist.' I think that helps people understand what you're making and the twist makes them go, 'Oh, and this is why it's original!' Then the twist can be used and explored to see, with this difference, how the setting would be different than other settings that have come before.

Tim Cain

co-creator of Fallout

Some of the best examples of this approach are Fallout (post-apocalyptic world + the 50s aesthetics) and Arcanum: Of Steamworks and Magick Obscura (classic fantasy world + industrial revolution).
According to Cain, defining a setting like this can lead you to what the main story could be because it already contains the main conflicts and points that you can build upon moving forward.

Story document

From this point, the main task is to make sure that the world and its stories will be interesting for players to explore in any direction and in any way they would want to.
Although Cain recognizes that there are different approaches to creating stories, he personally believes taht a role-playing game shouldn’t assign a character or any role to the player. So the designer’s task is to create a story based on a chosen setting and build elements around it for people to react to during the playthrough.
Both Fallout and Arcanum have fairy simple goals for the player in the beginning, but then they suddenly find themselves being involved in something bigger and more dramatic. These things should also be reflected in the story document.
Another important task is to make sure that any player, no matter what type of character they created, will find something interesting (quests, stories, etc.) while freely exploring the game world.

System document

According to Cain, game systems should support the setting both in tone and in actual mechanics.
That’s why Fallout, for example, not only had all these different skills that should help players survive in the Wasteland, but also things like drugs or radiation, because they were an important part of the world. And Arcanum had a special meter reflecting the bigger conflict between magic and technology.
One of the most important things to include in any system document is a set of goals for every mechanic. This allows you to justify why any particular mechanic is included in the game. “In The Outer Worlds, one of our high-level goals was that melee and ranged combat should feel different and offer substaintially different play experiences, but neither one should be significantly more powerful than the other,” Cain explained.
From this point, you should set specific goals for every mechanic written on every page of the document. Without doing this simple task, different designers and different teams won’t be able to make a cohesive game with well-balanced systems.

When you're developing a game, if your fellow developers don't agree with your goals, that is a very different discussion than whether your individual design elements achieve those goals. And you should have that discussion first and get everybody to either agree that these are good goals or at least agree that these are the goals you're going to try to achieve. If you don't have that, things will go bad for you. People will be making different games on the same team.