Interstellia

A journey from Saturn to the edge of a black hole: a collection of interactive 3D experiences that run in the browser, from a single main menu.

Repository: https://github.com/bhaktiutama/interstellia

Built with Claude Opus 5.5. The code, GLSL shaders, physics, test scripts and design documents were written together with Claude Code (Claude Opus 5.5), with the project owner directing, playtesting and reviewing every stage.

The experiences

01 Copper Corn Station (O'Neill cylinder)

Walk the inside wall of a spinning city. An 8 km O'Neill cylinder orbiting Saturn. City, fields and river wrap all around you, and a 63.4 s spin presses everything to the wall at 1 g. "Down" is always away from the axis.

Key number	Value
Cylinder length / radius	8 km / 1,000 m
One turn (gives 1 g at the wall)	63.4 s
City districts	14
Saturn eclipse per orbit	2.78 h

Feature	What you do
Tram and traffic	Trams with full interiors circle the city, cars queue at red lights, people cross at zebras
Lift to the zero-g axis	Ride the lift 1 km up to the axis hub as gravity slowly fades away until you float freely
KS-07 shuttle	Walk through the terminal to the dock, fly outside the station, then berth it yourself
150 km/h motorbike	A V-twin café racer; you feel heavier riding with the spin and lighter riding against it
Weather and Coriolis	Dynamic clouds and rain; rain slants 8 degrees and the fountain curves from Coriolis
Saturn eclipse	Every orbit Saturn hides the Sun for 2.78 h: the sunline fades, the limb glows

Keys: WASD walk, E action, M map, C bike, 8 cockpit, F photo.

02 Gargantua (supermassive black hole)

Fall past the line not even light comes back from. The GX-01 skims low over the accretion disk. Everything you see is computed by tracing bent light paths, not a painted backdrop.

Key number	Value
Missions	5
Disk gas at the ISCO (relative to the craft)	0.8 c
Critical capture / escape angle	24.62 degrees
Relay station distance	22 rs

Feature	What you do
Fall to the horizon	Fall straight in from the chase view or 3-screen cockpit on a limited delta-v budget
Skim the disk	Autopilot skims low to the ISCO, gas rushes by at 0.8 c, embers hit the glass
Signal relay	Fire flares to the 22 rs relay; a spacetime diagram shows why the craft clock freezes
Tesseract gate (fiction)	Freeze time, aim the entry angle at 24.62 degrees, then fly to the hypercube gate
Synthesized sound	Disk roar, creaking tidal strain, thrusters and relay beeps, all generated live in the browser
Photo mode	Hide the interface, tune screen effects, then save your gravitational lensing shot as a PNG

Keys: V craft, O autopilot, E flare, M relay, F photo.

03 Millar's World (water world)

One hour here, seven years pass outside. What looks like mountains on the horizon is a wave. A shallow ocean with no land near Gargantua, at 1.3 g. Find wreck pieces by radar, then fly the KS-07 out before that wall of water arrives.

Key number	Value
Surface gravity	1.3 g
Wave height / speed	1.2 km / 125 m/s
Time dilation	1 hour = 7 years outside (61,362x)

Feature	What you do
Radar mission	Find 3 wreck pieces with radar pings and run the fastest route before the wave hits
Living ocean	FFT waves with foam and caustics, ripples at your feet, a backwash that drags at you
Fly the KS-07	Climb into the 3-screen cockpit, lift off from the water and fly clear over the wave crest
Orbit and cinematics	Descend from orbit to the ocean surface, then leave again through reentry plasma
Astronaut body	See your own legs and gloves, a suit that gets wet, a visor with fog and water drops
Ocean sound	Wind, surf, your breath inside the helmet and the rumble of the giant wave drawing near

Keys: WASD walk, M radar, E pick up / board, V camera, U sound.

Coming soon: Kestrel Flight

Fly shuttle KS-07 from the dock to the rings of Saturn.

Common keys in every experience: Q graphics quality, P screen effects, U sound, V view, F photo mode, ` control panel, ? help.

Architecture: one experience = one HTML file

• Each experience is a single, self-contained HTML page (experiences/<id>/index.html) holding its CSS, JavaScript and GLSL shaders. The main menu is index.html.
• No build step, no bundler, no npm install. three.js 0.186.1 is loaded from a CDN through an import map; Gargantua is plain WebGL2.
• Data assets (models, textures) are plain <script> files with base64 data, so every page also runs straight from file://.
• Switching experiences is a full page load, so GPU memory is released cleanly between worlds.
• Shared code moves into shared/ gradually (for example shared/kestrel.js, the KS-07 shuttle and cockpit used by Copper Corn Station and Millar's World).
• Language choice (Indonesian / English) is shared by every page through localStorage (lazarus.lang) and the ?lang= parameter.

Running

• Open index.html in a recent Chrome, Edge or Safari and pick an experience. An internet connection is needed for three.js.
• Or serve the repository with GitHub Pages (Settings > Pages > branch main, root folder).
• Tested on a PC with a GTX 1060 and on a MacBook M1. Press Q to change the graphics preset (the lowest preset is tuned for the M1).

Repository layout

Path	Contents
index.html	Main menu with an infographic per experience
experiences/<id>/	One folder per experience: index.html, menu photo menu.webp, preview, data assets
shared/	Code shared between experiences
docs/	Concepts, stage plans and design notes (Indonesian)
tools/	Load checks, test scripts and asset preparation scripts (Python / Node)
CLAUDE.md	Project context for Claude Code

Languages

Indonesian (source) and English. Japanese and Mandarin are postponed.

Credits

• Café racer motorbike in Copper Corn Station: "moto guzzi v-twin" by Alexios Apokaukos, CC BY 4.0. Details in experiences/cooper-station/assets/KREDIT.md.
• Everything else (models, shaders, sound, the KS-07 and GX-01 designs) is original.

Disclaimer

A fan project for learning physics and 3D graphics. Not affiliated with any film studio. It uses no film titles, logos, music, footage or vehicle designs.

License

MIT, see LICENSE.