In Silicon No One Can Hear You Scream: Evolving Fighting Creatures

Virtual creatures operating in a physically realistic 3D environment, as originally introduced by Karl Sims, provide a challenging domain for artificial evolution. However, few coevolutionary experiments have been reported. Here we describe the results of our experiments on the evolution of physical combat among virtual creatures: essentially, we evolve creatures that trade blows with each other. While several authors have involved highly abstract forms of “combat” in their systems, this is (to our knowledge) the first example of realistic physical combat between virtual creatures, based on actual contact and physical damage. This poses the question of apportioning damage in a collision. Our solution is to assign damage proportionally to how much each colliding limb contributed to the occurrence and depth of the collision. Our system successfully evolves a wide range of morphologies and fighting behaviours, which we describe visually and verbally. As with our previous efforts, our source code is publicly available.