I believe that a new board, with all the variety it introduces, breathes new life into Terraforming Mars. That’s why Hellas & Elysium is one of my favorite expansions to the original board game and why I was super excited about Utopia & Cimmeria and Amazonis & Vastitas when they were announced. I thought it would be cool to be able to enjoy these boards on the digital version of the game since I’m spending disproportionately more hours playing TM online, saving the longer, 4-player offline sessions for every other weekend. Even though there is an official DLC for Hellas & Elysium, it’s unlikely that we’ll be seeing Utopia, Cimmeria, Amazonis, and Vastitas any time soon. So I set out on a journey to create my own mod to make it possible, learning a whole lot in the process.

The mod is still in development. I’m going to share more about the process in future posts.

For the rest of this article, when referring to the game, I’m referring to the digital version of Terraforming Mars, published by Asmodee Digital.

JS-based Board Generator

Today I want to showcase an external, web-based tool I made to aid in the creation of custom boards. The idea was to be able to create fully customized boards, and export them in a format that the game understands. The tool uses Honeycomb and SVG.js to calculate and render the hex grid. Everything else is vanilla HTML, CSS, and JS. To understand the inner workings of the game, I used the dnSpy .NET debugger and assembly editor. TM Board Generator

Features

This is a list of already implemented features:

  • Create hexagonal grids/boards of various sizes.
  • Set tiles as reserved for oceans.
  • Assign and remove bonus resources by drag-and-dropping.
  • Set tile costs (M€ the player needs to pay to be able to place a tile on that slot).
  • Mark tiles as volcanic areas.
  • Place resources (Microbe, Animal, Floater, Science, Asteroid) and bonuses (Oxygen) not used (yet) in official boards.
  • Save boards locally or load previously saved boards.
  • Export boards as a JSON file that the game can read.

I’ll probably implement new features as more ideas surface.

Hex Grid Size

Hex Grid Section Size, both in-game and in my tool, refers to the number of hexes on the equator row. All official boards have a size of 9, except Amazonis that has a size of 11. Changing the size constructs and renders a new grid.

Show Coordinates & Show TileIDs

Coordinates & TileIDs This is functionality I added to help me troubleshoot the export-import process. Show Coordinates renders the cube coordinates of each tile. These coordinates are stored in the TilePosition attribute of each tile in-game. There is a fantastic article by Red Blob Games on hexagonal grids that helped my understanding a lot; check it if you want to learn more. TileID is a number identifying a tile in game. The tile with TileID: 1 is the leftmost one on the top row. A size-9 board has 61 tiles in total.

Ocean or not?

Ocean Placement To mark a tile as reserved for oceans right-click on it. Clicking it again will revert it to a normal tile. In game this is stored in the EGridTileType enum, with value 0 meaning “Normal”, and value 1 meaning “Ocean”.

Resources/Bonuses

Resource/Bonus Assignment Note: I consider Steel, Titanium, Heat, etc. to be resources, while “raise Temperature”, “place Ocean”, etc. to be bonuses. The game doesn’t make a clear distinction between them so I’ll refer to all of them as simply bonuses

Adding bonuses to the board is straightforward: just drag and drop them on the tile you want. Each tile has a capacity of 3 bonuses at most (the tile cost “anti-bonus” counts as one). To remove a bonus left-click on it. Refreshing the page removes all resources.

In-game bonuses are stored in the enum EBonusType, so each bonus corresponds to a numeric value:

Card = 1,
Steel = 2,
Titanium = 3,
Plant = 4

Each tile has a Bonuses List that holds these numeric values. If, for example, I want a tile to have 2 Steel and 1 Plant, I should set Bonuses to [2, 2, 4].

Location Names

Location Name Assignment You can set a tile as a volcanic area by right-clicking it and selecting the desired name from the dropdown menu. Choosing “None” reverts the tile back to a normal one.

Like tile type and bonuses, location names are stored in an enum (EGridTileLocationName). The game makes heavy use of enums in general. “Extending” them at runtime has proven to be a real pain in the ass but more on that in the post(s) regarding the mod.

Randomizer

Randomizer Section The tool features a randomizer for spreading oceans and bonus resources.

Randomizing Oceans

You can choose the minimum and maximum amount of tiles reserved for oceans to be set by the randomizer. Official boards (besides Amazonis) have 12 ocean slots (9 for ocean tiles and 3 for special, ocean-only projects, such as Mohole Area). This is something to keep in mind when designing a board. Nevertheless, I thought it would be fun to experiment with boards that have more (or less) ocean slots, as long as they can be fully terraformed.

Randomizing Resources

You can tell the randomizer that you don’t want a resource included on the board by clicking on its respective icon. The icon will turn grey to reflect that. The randomizer doesn’t place Ocean, Oxygen, and Temperature bonuses, neither assigns cost to tiles. There is a logic based on weights that affects two things:

  1. The proportion of tiles with 0 (50%), 1 (30%), 2 (17%), or 3 (3%) resources.
  2. The probability of appearance of each bonus (some, such as Plants, are more common than others).

I chose the weights after studying the bonus distribution of the official boards. The idea is for the randomizer to churn out a semi-balanced board to act as a starting point for further manual editing. There is no way to change the weights from the UI at this moment, but I may introduce one in the future.

More ideas

  • There are still some expansion-dependent bonuses to add, such as the Colony (Colonies) and the Delegate (Turmoil). Implementing the mechanics of the expansions needed for these bonuses to make sense would be an immensely difficult undertaking, so I’m going to skip them for now.
  • Find a way to change the Mars texture that acts as a background for the grid based on the board used. This is something that the game does already for Tharsis, Hellas and Elysium.

Using the board generator in conjunction with the mod (in its current state) I was able to create fully playable custom boards, which is a promising start.