#research #worlds #economy #mmo #set #target #mix-regulate


A research project to mix-regulate economy in MMO worlds

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Uses old Rust 2015

0.2.1 Mar 15, 2024
0.2.0 Oct 25, 2016
0.1.0 Sep 13, 2016

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A research project to mix-regulate economy in MMO worlds


The black curve is without a Gini solver, the red curve is with a Gini solver set to target 0.2

To run the demo, fork the repository and type cargo run --example demo.

Blog posts

Why mix_economy?

A virtual economy is an emergent economy existing in a virtual persistent world, usually exchanging virtual goods in the context of an Internet game.

One challenge is to balance gameplay to be fun for both causual and experienced players, which most small to medium MMO games do not have substantial resources to do.

This research project studies a simple model that can be mixed with an existing economy model:

  1. A normalized threshold sets a soft limit of the wealth of a player.
  2. Money "burns in the pockets" of rich players, encouraging spending.
  3. Controlled inflation charged by "total lack of money".
  4. Rewards weighted as negative tax on fortune (more money = more rewards).

At start of joining the game, each player gets a start fortune. Each player receives money rewards at regular time intervals.

The rewards increase with the amount of money, meaning that saving or earning money is beneficial to the player.

Rewards are charged through the lack of money in circulation, by summing the difference from the soft limit of wealth. This means inviting new players to join is beneficial for all players.

Text example 1

A game has an infinite resource reserve that requires a minimum amount of time to mine. By buying an expensive equipment, the resource can be mined faster. A player owning the expensive equipment can sell the resource to other players, for a cheaper price than these players earn during the same amount of time required to mine the resource. This means a huge cash flow from many players to some few players, which they then invest in other equipment or spend on other goods or services to keep the value of that cash flow from disappearing.

Text example 2

A player want to take on a mission that takes a long time. The reward for this mission could be an expensive equipment. By living off the saved fortune and regular rewards, the player can take on the mission without worrying about running out of money.

Other players can provide support with risk for themselves, even if they do not get the reward directly, but in order to reduce the overall cost of a resource.

Text example 4

Items could be "programmed" to allow greater flexibility. This will lead the players to find creative ways to make money.


  • Develop an economic model that makes gameplay fun for both experienced and casual players
  • Make it work for "complex" environments
  • Research algorithmic properties and interaction with gameplay


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