Feed the Fire: a simulated fire pit, drawn in voxels

FEED THE FIRE

A fire you can feed.

This fire is not an animation. It is a small simulation in three dimensions: air that rises when it is hot and is drawn in from the sides to replace it, gas given off by hot wood and paper, oxygen that the flames use up, smoke, and steam.

What you drop in changes it through what it is made of. A log steams, then catches slowly, burns for minutes, glows as charcoal and falls apart into ash. Paper catches at once and is gone. Oil pools and burns hot. Water soaks in and has to boil off before anything burns again, which is why it puts a fire out. Copper and potassium salts give off vapours that burn green and violet where the air carries them. A kettle boils, steams from its spout, and whistles.

Water on burning oil is the one thing not to do: it sinks under the oil, turns to steam at once, and throws the oil into the air as a fireball.

It is a winter night. The snow melts back from the fire. Turn on falling snow in the Look panel and it melts in the hot air above the fire, so you can see the shape of the heat.

Nothing resets between drops. The fire you see is the one you made.

Choose something at the bottom, then click the pit to drop it. Drag to look around; scroll or pinch to zoom. If the fire goes out, strike a match.

The fire is drawn by sampling the simulation on a grid of voxels and keeping each one only where there is enough fire, smoke or steam to pass a threshold fixed to that spot. Thin fire keeps a few voxels; dense fire keeps them all. The Look panel changes the voxel size (Auto picks what your device can keep up with) and the threshold pattern, can turn the dithering off, can show heat or spent air instead, and sets how much snow falls.

Made with code written with AI. No images, models or recordings. The sound is generated in your browser from the simulation.