Quaternion Julia

Watch Quaternion Julia live in the browser

A pale, coral-like body floats in the dark, lit from two sides, its lobes and tendrils shaded with soft occlusion and banded in two colours. The camera circles it slowly while the shape blooms, splits and reconnects.

The body is a 3D slice of a Julia set in four dimensions. Every point is a quaternion q, repeatedly squared and offset by a constant c (q → q² + c), and the surface marks where orbits stop escaping. It is raymarched with a distance estimate built from the running derivative. The constant c travels a loop of values that keeps the set connected and intricate, and the fourth coordinate of the slice moves back and forth, so a different cross-section of the 4D object is seen at every moment.

What it reacts to

• Bass: slides the 3D slice through the fourth dimension, reshaping the body
• Mids: nudge the constant c, shifting the form slightly
• Kick drum: a warm flash of the surface colour that fades within a fraction of a second
• Loudness: the rim light brightens, and the morph and camera orbit advance faster

Tune

Detail sets how fine a surface the raymarcher resolves, and Color A and Color B are the two tones whose bands wrap the body.

Music that suits it

Bass-led music with slow phrasing, such as dub, downtempo or ambient with a deep sub, makes the slice glide visibly through the fourth dimension.

How to play it

Install Deus, play music on Spotify, YouTube Music, Yandex Music or any other tab and click the Deus icon on that tab. Then pick Quaternion Julia in the WebGL presets, or press ← → on the page until it comes up.