Studying emergence, it's quite useful to have a development framework to build upon to quickly test out new ideas. 3d with physics collision would be nice, and open-source would be a big plus. For this purpose 'breve' looks quite promising, but I was wondering if anyone had used it or knows of any other suitable engines?
Actually, I think that something like Microsoft Robotics Studio would be good for this.
For quick development, breve does look appropriate. If you want to write something more from scratch, ODE, Bullet and Tokamak are all good open-source 3D physics and collision detection libraries.
If I understand the question right, what you're looking for is more a programmable 3D graphics / physics engine sandbox to try out ideas, than anything specifically to do with artificial life.
If so, you might want to take a look at fluxus - it's basically that, where the "programmable" part is Scheme. It's designed for interactive programming (draw 3D scenes and animations, then change them in real time), so I'd guess it should be flexible enough for agent-based AI/AL.
Maybe not 100% what you are looking for, but you can try Open steer as a possible starting point.
I would go ahead and use breve. If you hadn't mentioned breve in your question, I would have recommended it.
I'm looking for the same thing. Breve seems to be an abandoned project. I've read that with python doesn't work properly but it in the web it's said that it has no support for steve anymore.
I asked a similar question recently with respect to robotics simulation.
JBullet (a Java port of the Bullet Physics engine) came out as the top recommendation.
I'm using this in combination with jMonkeyEngine (which is a fully featured and popular game engine) for the rendering, camera control, scene graph management etc. This seems to be working very nicely so far as the two have been designed to work together.