Welcome to the Expression website! Expression is an animation system based on an anatomical model of the face. Using basic muscle simulations instead of morph targets, Expression simplifies the creation of lifelike characters, allowing a face to be set up in a matter of hours instead of days. Written in C++ and OpenGL, Expression is a general-purpose framework for real-time facial animation in games and web applications.

Expression is being released under both the QPL and a commercial license. See the licensing page for more info. 

Expression originated at Altiverse Systems, a company that was working on large scale persistent worlds that unfortunately ceased operations recently due to financial reasons. For more about Altiverse Systems, see the FAQ.


December 28, 2004 - Posted Linux Port of expression.

Clement Raievsky has been kind enough to submit a Linux port of expression. You can download it here. Note I haven't heavily tested it, so if it works for you let me know.

December 27, 2004 - Interesting Facial Tracking Research.

Jose Buenaposada is doing some cool real-time analysis of faces and mapping them to the Walter's model of the face:

Feb 29, 2004 -  new project using Expression: Ebba

Ebba a project by Carl Hasselskog is aiming to develop an advanced chatbot by combining AIML, facial expressions, speech synthesizer and commonsense databases. Head over take a look. Carl's got expression talking again in this case using pipes and a chatbot. Head over and check it out.


Oct 31 2002

New demo of Expression up grab it to the left. What's been changed. Also there are some new demos of other projects I've been working on here. I'll be posting the code in a few days.

July 31 2002 - Update ( and job hunting )

oops, has it really been a year and a half since I've updated this page. 

  There has been a steady trickle of interest  in Expression. But very few things have been worth posting. A few people who've mucked around with the code, as far as I can tell the most interesting was a port to OS X. I've spent some time cleaning up the code base in the last few months, it's rather amazing what a 18 months working on a 1.2 million line code base will do to your sense of what code should look like, I've broken some features so I'm not bothering to post it but you can contact me directly if you're interested.

  Some of the expression content wound up in interesting places, including the cover of a Thesis. Considering that the content was my own face I found it a bit surreal. There have been a few grad students who have incorporated expression into their work.  I presented Expression at Columbia University as part of a lecture on software engineering and online games. 

I been insanely busy working on the graphics tech for Asheron's Call 2 till last month. I'm now looking around for new interesting projects.

January 4 2001 - Misc.
14 December 2000 - Code's Up - Posted by Gedalia

Close eyes.. breathe deep.. give prayer to preferred deity... Download here   

12 December 2000 - Version 1.5 Release/ SourceForge Problems - Posted by Gedalia

  This should be available in sourceforge as soon as they get their file release script fixed.  Unfortunately there are a few dozen projects that currently can't release code. I don't have an E.T.A. If I don't see a fix by tomorrow, I'll start looking for a mirror. 
   If you're really itching the code is available in via CVS. 

  Major Functionality Changes: Added Skeletal Animation System, as well as functionality for compositing the expression and head key frames, a new win32 Skeletal Animation Playback demo (skel view), new content (alien mesh and skeletal animation files), new bat files allowing view of content. For more info see Release Notes.
  I've also updated instructions for setting up the system , as well a short overview of the way the compound expression file is formatted. And added a Contributors page to give credit to people that are helping with Expression's Development.

3 December 2000 - Version 1.5 Demos

  Well I solved most of the rotation problems. The new demos include the playback app, the text to speech app (a MS Text To speech engine installed) and two models a Human head (me) and a weird 30K polygon alien. 
   A new code release and creation docs should be up by the end of the week. 
P.S. I'm still job hunting.

28 November 2000 - Skeletal System

  The playback application now supports Skeletal System characters. However I had to overhaul a whole lotta stuff to get it to that point. Most of the changes are internal. But the Adapter has changed slightly. For the life of me I can't get the eyes and the jaw to rotate properly. Think it is due to the fact that I'm now inheriting transforms which is messing up what used to be straight   forward rotations.

17 November 2000 - MAJOR Issue Discovered

DAMN!  Now that I have some free time, I've discovered that the binary mesh exporter that was uploaded was the original open source one from Discreet, not the one with all of my modifications. My apologies to anyone who has had problem using it.
Update: The new release is up. I strongly suggest grabbing it. I've done quite a bit of code cleanup in the last 3 weeks as well, so it should be much simpler to tell where things are happening.  

15 November 2000 - Gedalia Looking for work

In a bizarre twist of fate, I was laid off today. Gotta love the New Economy. So if anyone is interested in bringing in a consultant for integrating Expression into their existing system, drop me a note. My resume can be found here.

14 November 2000 - Expression is in the news again!
9 November 2000 - Expression is in the news! - Posted by Gedalia