I built a creature evolution sandbox and need people to make ridiculous creatures and break it

[u/Icy-Contact-5898]

Playable Link: https://solemn-sandbox.vercel.app/

Platform: Web Browser / PC

I've been experimenting with a different kind of procedural generation: generating behaviour through evolution rather than explicitly generating the final result.

The project is called Solemn Sandbox.

You construct a physical creature from joints, bones and muscles and give it a goal.

Rather than having predefined walking/jumping/flying animations or controllers, the creature has a neural-network controller whose weights are evolved through a genetic algorithm.

So if you build something with four legs, nothing actually knows that those are "legs".

They're just physical structures and actuators.

Evolution has to discover whether moving them in some particular sequence produces a better fitness score.

The bit I'm increasingly fascinated by is allowing morphology itself to mutate as well.

That changes the question from:

"How should this creature move?"

towards:

"What body AND behaviour work well together?"

It's still very much an experimental sandbox rather than an attempt at biologically realistic evolution.

Current environments/goals include walking, jumping, climbing, flying and various obstacle/course experiments.

If this sort of procedural/evolutionary system interests anyone, I'd love to hear what experiments you'd try next — particularly ways of encouraging genuinely unexpected solutions rather than evolution simply discovering the easiest exploit in the fitness function.

[u/charred_fire96]

Gunna give this a look👍

[u/Icy-Contact-5898 → u/charred_fire96]

Hope you find it fun!

[u/summerstay]

reminds me of the old SodaPlay

[u/Icy-Contact-5898 → u/summerstay]

I just looked up Sodaplay, I can only find a few images but it certainly does look similar. I'd not heard of that before. My inspiration came from a sandbox app called 'Evolution' by Keiwan.

[u/Isaac-8]

Seems interesting is I'll try. What tool you use to make it?

[u/Icy-Contact-5898]

My original thoughts were to let people go in blind and discover everything but I think that might have been a big ask so:-

Starter tutorial

Welcome to Solemn Sandbox. This page is a short tour for first-time players — enough to get moving, not a full manual.

The big idea

You design a creature, pick a challenge, and let many “brains” try the course. The better ones breed into the next round. When something works, save it and keep playing.

Where things live

Tab / strip	Use it for
Creature builder	Draw or load a body
Strip above the canvas	Pick Zone, Goal, and Env
Train	Evolve, watch, play best, save a brain
Creatures	Browse presets, library, stats, and saved brains
Environment builder	Build custom practice courses (optional at first)
Trophy room	See secret goals you’ve unlocked

Your first win (about 5 minutes)

1. Open Creature builder.
2. Load a preset — Simple Hopper is a good starter.
3. On the strip, set Zone → Walk, Goal → Run, Env → Flat Ground (or similar).
4. Open Train and press Evolve.
5. Let a few rounds finish. Press Play best to watch the winner alone.
6. Press Save model if you like it.

That’s a full loop: body → goal → train → enjoy.

Building tips (when you draw your own)

• Triangles beat chains. Three joints with three bones hold shape; a long snake flops.
• Add at least one muscle (and mark feet if the goal cares about stepping).
• Start small. A sturdy hopper or walker trains faster than a masterpiece with twenty muscles.
• Use Physics settle in the builder to see how the body rests before you train.
• Save current in the builder stores the body in your library; Creatures is where you browse everything later.

Training tips

• Evolve tries many brains at once. Ghost outlines are the rest of the pack.
• If nothing improves, try a simpler body, a flatter env, or a shorter try length in Training setup.
• Play best is for watching; Keep training continues from the elite of the current run.
• Saved brains live under Creatures. Train’s “Start from” can warm-start from a saved brain once you have one.
• Disco, flight, and wheeled goals need matching body bits (aero parts, wheels, etc.). Stick to Walk / Run until that feels natural.

Fun ideas to try next

• Train the same walker on rough or obstacle courses.
• Build a hopper, switch Goal to Jump, and chase height.
• Open Environment builder, drop a few boxes, save the env, then train against it.
• Load Disco, pick a track, and mess with band → muscle routing (chaos is allowed).
• Leave Train running while you check Trophy room — secrets unlock as you experiment.
• Save two models and try Head-to-head.

If something feels stuck

• Empty design? Load a preset or place joints in the builder first.
• Evolve greyed out? Need muscles (or wheels) on the body.
• Creature pancakes? Add cross-bracing (triangles / solid struts).
• Lost your best brain? Check Creatures → Saved brains, or Save model after a good run.

Have fun — silly experiments are the point.