Actually, there aren’t evolution based locomotion optimizers (that I know of), but there are reinforcement learning based ones (much fast and more efficient). It actually probably won’t be very difficult. You just need to use stable-baselines3 reinforcement learning library and then use an existing openai gym format for whatever walking robot you want to experiment with. I think there are gyms available for humanoids and quadrupeds. You could get it running by following stable baselines3 tutorials.

Unfortunately, these optimize control policies, not the actual robot designs itself which I assume is what you want. Theo Jansen (strandbeest guy) used an evolutionary algorithm to come up with his design which I think is what you want to do. I’m not aware of any existing software that lets you do that though.

You could implement it yourself in python or C++ using robotics oriented rigid body dynamics libraries and solvers. But if you haven’t done this before it will be pretty hard.

This is actually something I want to do at some point too but I’m busy with other projects right now.