It seems to me that there is a dearth of information on the internet with regards to simulation in games. While looking for information regarding techniques used in simulation games such as SimCity and business strategy games like Rollercoaster Tycoon, I found almost no information on the subject. I found better success looking for information on simulation in general; I found some information while scouring sites for university courses on business simulation. I also found a few books that deal with simulation for business purposes, but I was hesistant to buy them because I wasn''t sure which one(s) would be most informative and useful for what I''m looking for. I guess what I''m asking is, am I looking in the wrong places? Am I using the wrong terms for these sort of games? I''m really interested in how simulation is used in games, but it''s been really difficult to find a lot of information on the subject. Does anyone know of or can recommend any resources/books/information regarding simulation in games, or simulation of systems in general that can be applied to games? I''d appreciate it if you could even give me some better terms that I could use in a google search - ones that I usually use are "simulation of business systems," "simulation of business processes", "business simulation."

You could ask me (nicely) about the whopper collection of algorithms that I have constructed to simulate airline passenger behavior in my game, but I''m not sure I can tell you about it yet!

Dave Mark - President and Lead Designer
Intrinsic Algorithm - "Reducing the world to mathematical equations!"

Is the main technique in simulation games merely to take the actual systems, model them into rules and processes, and then create simulated "people" that go through the rules and processes? If that''s the case, then would I also be safe in saying that the two main focuses simulation in games would be to create realistic and detailed processes, as well as creating simulated "people" that react realistically and make decisions within those processes?

I have one more related question: does the greatest difficulty in creating a simulation for use in a game result from creating the customers or people that go through the processes, or from creating the algorithms to model the processes, or both?

Each game design has its own difficulties so that is hard to answer in blanket form. However, in the games that you mentioned, i.e. SimCity and Rollercoaster Tycoon, much of the difficulty would be in recreating reality in a variety of forms. In RCT, for example, there is the recreation of physics for the coasters, a reasonable method of converting stimulus into reaction (e.g. "intensity", "excitement", "nausea") and then contstructing the people''s decision making process around those variables.

Dave Mark - President and Lead Designer
Intrinsic Algorithm -
"Reducing the world to mathematical equations!"

There are two main approaches to modelling social and economic systems: process based and agent based. The process based approach tries to model the key parameters of the system by a set of equations. So, for example, a model of the stock market would attempt to model stock prices, or market indicators, utilising information such as the number of shares issues, number available, number of buyers, number of sellers, etc, etc,... A process model for the interactions of a group of people would be harder to define, but might model things like clique sizes, who-knows-who, information passes around, etc. I know that''s a little nebulous, but I''m trying to highlight the fact that the process model is an approximation of the system dynamics made by an outside observer. The process model implemented may have absolutely no bearing to the true underlying dynamics of the system, except for the fact that it should give similar results given an input state.

An agent based approach though seeks to define agents such that when these agents interact (according to the defined actions each agent can take) the end effect is a social or economic system (or something similar). There was some excellent work done on such systems at the Sante Fe Institute during the late 80s and early 90s. You might want to look there for references.

There is also a game in development at the moment (although I don''t recall the title) that utilises the agent based approach for interactions within the game. It''s based heavily on psycho-social and behavioural models of humans. I came across it earlier this year in a Gamasutra feature article, so that would be the place to start looking.

I hope this helps, at least a little, in your endeavour.

Cheers,

Timkin

Agent based relies heavily on emergent behavior and, therefore, can be a bit touchy.

Dave Mark - President and Lead Designer
Intrinsic Algorithm - "Reducing the world to mathematical equations!"

I''m just trying to make sure I understand the difference between agent-based and process based systems.

Take Rollercoaster Tycoon, for example. Does it use an agent based or process based approach? From looking at the game, I would have to guess agent-based, since it seems to be based on the idea of little people wandering around the theme park and interacting with various rides. Am I misconstruing the concept of the agent-based approach?

Innocuous Fox: What approach would you say that you used/use in your game?

A lot of times you are going to use both. In RCT, there is a process based model using formulas to calculate the stats for the coasters. The people are little agents wandering around interacting with their environment seemingly of their own accord based on their own preferences.

For my game, I am also using both. I have to model a lot of complex information such as generation curves to create realistic passenger traffic. However, once created, each passenger, airline, aircraft, gate and even runway is reacting and interacting with the other agents based on a series of behavior models that I have put into place for each agent.

Dave Mark - President and Lead Designer
Intrinsic Algorithm - "Reducing the world to mathematical equations!"

One final sorta related question: Simulation is not considered a part of the field of artificial intelligence, correct? So was I wrong to post my question in this forum? Just for future reference in case I have any more questions concerning the subject.

[edited by - ares32585 on July 31, 2003 6:53:17 PM]

That depends on what it is you are talking about... In a lot of ways, I believe the two are related. However, much of it depends on what you are modeling. If you are modeling the mathematics behind business decisions or the stock market, in a way that IS AI in the sense that you are trying to determine a way to algorithmicly and formulaticaly recreate something which is normally driven by human intelligence. If you are trying to recreate the physics of a bouncing ball, that is not necessarily AI in the classic sense, although AI programmers are often called on to resolve the physics of such things as bouncing balls, line of sight checks, etc.

Dave Mark - President and Lead Designer
Intrinsic Algorithm -
"Reducing the world to mathematical equations!"