SunaBox

Paint matter. Build machines.
Every drop remembered.

SunaBox is a physics sandbox in the spirit of the legendary OE-CAKE — 27 kinds of matter you paint straight into the world, machines that really run, and fire that really spreads. It runs free in your browser, and because its engine is bit-exact, every session can be replayed, rewound, and shared as a few kilobytes of proof.

Play in your browser Meet the engine
Free in browser 27 materials Opens OE-CAKE .oec files Deterministic replays Coming to Steam

What you can do

Paint 27 kinds of matter

Water, gel, oil, mercury, acid, nitro, rice, rubber, wood, stone, metal, ice, lava, fire, smoke, steam and more — each with real thermodynamics. Ice melts, wood burns to ash, steam condenses, nitro does what nitro does.

Build machines that run

Weld strokes into rigid bodies, pin them on axles, drive them with jets, stretch rubber into slingshots, or take the controls yourself — arrow keys drive what you paint.

Import anything

Drop a PNG into the world and it becomes matter — your drawing, your photo, rigid or fluid or flammable. Old OE-CAKE .oec scenes open too, preserved exactly.

Rewind time

The engine is bit-exact, so a session is a starting state plus your inputs — a few kilobytes. Replay it, scrub it backwards, share it as a link that provably reproduces the same world, bit for bit.

Classic Mode

One toggle and the toolbar becomes OE-CAKE's, laid out exactly as you remember it — same buttons, same order, same feel, fifteen years later.

An open engine

SunaBox runs on SunaEngine, our open-source (AGPL-3.0) bit-exact physics engine. The claims are proven live, on your GPU, at engine.sunabox.dev.

The love letter

In 2007, Prometech Software released OE-CAKE! — a demo of their OctaveEngine that became, almost by accident, one of the most loved physics toys ever made. It disappeared; the community that traded scenes and tricks for fifteen years never did.

SunaBox is our love letter to OE-CAKE! and to that community: a clean-room reincarnation, rebuilt from scratch for the modern browser, that opens your old .oec files and honors what made the original feel alive — then keeps going where 2007 could not.