IA on AI

Posts Tagged ‘Michael Mateas’

Raph Koster on Dynamic POIs

Monday, May 24th, 2010

Raph Koster, best known as the lead designer of Ultima Online and the creative director for Star Wars Galaxies, wrote an interesting post on his blog at the end of April. In the post, “Dynamic POIs“, He discusses how, in Star Wars Galaxies, they constructed a method for the computer to generate automatic content in the MMO world.

The term POI stands for point of interest and dates back to his UO days. At the time, those POIs were hand-placed by the design team. In a world the size of SWG, this was simply not feasible. He comments how even a room full of junior designers churning these encounters out was simply not enough. The proposed solution was to algorithmically generate these locations and fill them with life.

One of the complicating factors in this was that they weren’t simply placing the D&D staple of a wandering monster. They were generating a camp or facility full of these agents complete with scenery… and plot. Here’s a quote from the article that explains it better.

Don’t roll up just a bandit; roll up a little bandit campsite, with a tent, a campfire, three bandits, one of whom hates one of the others, a young bandit who isn’t actually a bad guy but has been sucked into the life because he has a young pregnant wife at home… In fact, maybe have an assortment of bandits — twenty possible ones maybe. Then pick three for your camp. That way you always get a flavorful but slightly different experience.

So what we are looking at is a random type of encounter with a random population, in a random location. So far that’s pretty groovy. If you want a description of what it was like, SWG producer, Haden Blackman writes about his own encounter with a dynamic POI.

One advantage that they had with SWG that didn’t exist with UO is that the SWG map was procedurally generated in the first place. That made generating a random encounter simply an extension that was over and above the map generation. They could create and destroy these places by simply making sure there was no one around.

…it was just as hard to create the dynamic content as it was to create static content.

In order to provide some variety, these encounters could also be designed modularly. The actors might be different or they may send you on different missions than a similarly constructed encounter elsewhere. The n-complexity of available encounters rises fairly quickly that way, of course.  Unfortunately, Raph says they weren’t quite able to make this whole process completely data-driven. The result is that it was just as hard to create the dynamic content as it was to create static content. In particular, the scripting of the encounters was tricky. The result of all of this is that dynamic POIs ended up coming back out of the game.

He hasn’t written off the entire idea yet, however. Neither have I. In fact, I spoke about it a little at GDC Austin in 2009. (Get my slides here.) Raph was not able to attend that lecture (for which I believe Sheri Graner Ray gave him a tongue-lashing). I don’t pretend to solve the problem of dynamic content to the extent that Raph writes about. The point I addressed was that there are ways for AI-controlled NPCs to dynamically deal with a shifting population and environment that can lead to more expressive encounters game-wide.

Anyway, with the advent of dynamic pacing in Left 4 Dead via the much-referenced AI Director, there is a lot more attention being paid to how we can break out of entirely hand-placed, hand-paced, and often linear content. Additionally, while the public’s appetite for “sandbox” worlds is increasing — thanks in no small part to games like GTA4, the industry can’t sustain GTA4-like budgets of $100 million for very long. If the procedural content issue was solved (or at least furthered along somewhat) then we can satisfy both the demands of our players and the restrictions of budget.

One place to look might be to the work that is being done by the likes of interactive fiction writer and programmer Emily Short and the work that is continually being done by Michael Mateas and the Expressive Intelligence Studio company and UCSC. Someplace in there is a hybrid of dynamic, data-driven storytelling that we can eventually work with to create truly open-ended content.

We can only hope… and work.

AIIDE 2009 – The Photoshop of AI Debate – Michael Mateas

Monday, October 19th, 2009

The following are my rough notes from Michael Mateas’ invited talk. He continued the “Photoshop of AI” debate that was started by Chris Hecker at GDC 2008 and continued at a panel at the 2009 AI Summit at GDC. To sum up what he presented, he basically said it was a non-issue because it was based on a number of false premises. Here are my notes:

Recaps Chris Hecker’s 2008 talk on the subject. Talks about what the panel at the 2009 AI Summit said on the subject.

Photoshop of AI is a mirage:
Grossly underestimates the size of the AI problem.
Overestimates the intuitiveness of visual art production.
Doesn’t take seriously the property of conditional execution.
DOES highlight the authoring problem in AI.
False premise that graphics and AI are set up as equals.
The problem of representing 3D space is the same from game to game. Quake to Prince of Persia to Bioshock.
From AI NPC, e.g. Thief compared to Madden. NOT the same problem. Many examples of how different games pose different problems.

Representing graphics via the texture mapped triangle is infinitesimally small compared to representing AI via code.
Graphics represents the problem of renaissance perspective. Invents a specific style of representation.
AI represents almost everything else. AI is NP-Hard.
Book: Noah Waldrip-Fruin – Expressive Processing
Hecker’s desiderata for style DOF’s
Photoshop is not really “intuitive”. 17,133 results on Amazon for books about how to use Photoshop… 1602 since January 2009. So much for intuitive.
Photoshop builds on millennia of practice in the visual arts.
Even if Photoshop is hard to learn, it may still be “intuitive” for trained visual artists.
AI Designer is a new type of artist. We have no pre-existing practice for us to be “intuitive” relative to. “A new kind of artist working in a fully computational medium, focused on the aesthetics of behavior.”
Essence of AI is that it is a conditional process executing over time… not static. The style of such a process lies in its conditional decision making. Different in kind from the static nature of the triangle/texture decomposition.
Spore Galactic Adventures… people could create creatures but not quests. Creation of the creatures was immediate feedback, but creation of questions… only way you can test it is to play it over and over because it is procedural.
Static artifacts support immediate global feedback. What would that look like for AI? You can’t get the static visualization feedback from AI.
Birth of AI was declaration that computer is a general symbol manipulation machine (not just calculator).
Re: Façade
Is it data-driven? No
It must be scripted. No.
WTF? (Fairy dust!)
People think either in terms of floats or in imperative code. Instead, Façade is based on blendable symbolic behaviors.
Instead of data-driven AI, think in terms of knowledge-driven AI. Classic AI approach is to create a knowledge-representation language that solves a specific problem you have, and then write the reasoning system (interpreter) for that language. Starts to sound like a structure vs. style decomposition.
Related to scripting, but far more general. Every scripting language that he has seen has been imperative – like C.
Agree with Chris that game AI must be authorable… BUT, there is no:
Universal solution
Magic numbers-and-flags only representation
Pre-existing artistic tradition we can leverage
How do you know if what you are doing is any good?
Authorial Leverage…
Leverage = (Quality * Variability) / Effort
Sims 3 = rule-based language with custom predicates and custom actions for designers to write the rules for world effects and state changes. E.g. “if this social practice is carried out in this situation, what would happen?” Custom KR model (knowledge-driven AI). Not the Photoshop of AI in Chris’ sense because it is not universal. It is domain-specific.