Buildable evolution

Abstract

The most interesting results in Artificial Life come about when some aspect of reality is captured. In the mid-1990s, Karl Sims energized the AL community with his ground-breaking work on evolved moving creatures [28, 29]. The life-like behavior of Sims' creatures resulted from combining evolved morphology with a physics simulation based on Featherstone's earlier work [9].The question that begged asking was: can a similar thing be done in the physical world? Can we make creatures that walk out of the computer screen and into the room?Two components were required: a language to evolve morphologies that have real-world counterparts, and a way to build them --- either in simulation or by automated building and testing. We set out to demonstrate that buildable evolution was possible using a readily available, cheap building system --- Lego bricks --- and an ad-hoc physics simulation that allowed us to study the interaction of the object with the physical world in silico; with respect to gravitational forces at least. The result [10, 14, 12, 13, 15, 16, 25, 23, 26, 24, 27] is a system that can evolve a variety of different shapes and is very easy to use, set up and replicate.Here I present an overview of the evolvable Lego structures project. Coinciding with the publication of this article, the source code is being released to the community (demo.cs.brandeis.edu/pr/buildable/source).