Simulated Bipedal Creatures with Muscle-Based Locomotion

HN cites it as an earlier, smoother precedent whenever new learned-locomotion or simulated-walking work appears.

A 2013 research demo of simulated bipedal creatures whose natural gaits are found by optimizing muscle-based controllers, with no motion capture or keyframe animation. It shows physics-based walking and running emerging from musculoskeletal models.