26
Mar
13

How to build a constraint propagator in a weekend

This is a tutorial that Leif Foged and I did for the AI summit at GDC on how to build your own finite-domain constraint solver using AC-3.  It’s won’t solve the really hard problems that high-end SAT solvers can solve, but it’s very fast for problems with a lot of solutions; fast enough to run in a game engine:

      http://www.cs.northwestern.edu/~ian/GDCConstraintsHowTo.pdf

Comments welcome.  I intend to keep revising it, since it isn’t archivally published.

 

12
Jan
09

New paper on procedural animation

This is a longer, journal paper on the Twig procedural animation system, submitted to the new journal IEEE Transactions on Computational Intelligence and AI in Games (full disclosure: I’m an associate editor).  This paper documents a fair amount more than the AIIDE paper, including object manipulation scripting, and a little bit about the authoring tools.

12
Jan
09

New paper on inference/action-selection – comments welcome

This is a paper I wrote for ICFDG that takes some work from my previous life as a roboticist and applies it to Twig (the procedural animation system I’ve been working on).  However, it’s situated in a tradition that the games community, and even the present-day AI community isn’t very familiar with, so much of the paper is an attempt to survey and explain the literature on using combinational logic for inference – why you’d want to do it, why it’s limited, and what you can do to overcome some of the limitations.  And even then, I’m worried that it won’t be transparent to the reader; not because it’s technically difficult, but just because the motivations won’t be clear.  Anyhow, any advice would be welcome.

09
Nov
08

fall symposium talk slides

Here are the slides from my position paper at the AAAI Fall Symposium on Naturally Inspired Artificial Intelligence.

27
Oct
08

the passing of a friend

Patrick 1  image image

 

My friend Patrick Welch, a painter, comic artist, and professor at the Illinois Institute of Art, passed away recently.  He will be greatly missed.  Drink a beer for him for me.

25
Oct
08

my other blog

I’ve been maintaining a separate blog that’s specifically for Twig, the procedural animation system I’ve talked about a little here.  You can find the blog here.  At the moment, it’s more active than this site because that’s where most of my limited hacking and thinking cycles are going.

The blog also includes pointers to the episodes of a “webcomic” that I’m doing with Twig as a way of testing out features and guiding feature implementation.

19
Aug
08

Final version of AIIDE paper on procedural animation

This is the revised version of the AIIDE paper on Twig, the procedural animation library I’ve been working on.  I’m going to do a longer journal version of it, so suggestions are very welcome.




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