Skywalk Loy Krathong

A river of krathongs, three storeys above the traffic. For Loy Krathong 2024 the City of Bangkok brought the festival to the OneSiam Skywalk — the elevated deck over the Pathumwan intersection, strung between MBK, Siam Discovery and the Bangkok Art and Culture Centre. There's no canal up there, so we made one out of light: visitors decorate a krathong on their phone and send it onto a ring of projection wrapping the walkway, where it joins a slow, glowing current of everyone else's. It's Loy Krathong rebuilt for the heart of the city — the wish, the krathong and the water, all suspended above one of Bangkok's busiest crossroads.

Scan, decorate, send. It opens in the browser — register, no download, pick your language (Thai · English · 中文) — and the first move is physical: find one of three release points on the skywalk and scan its QR. That drops you into the maker, where you build your krathong piece by piece: choose a base, add flowers, set the incense and candle, finish it with stickers and emoji. When it's yours, you send it — and it lifts straight onto the play screen, taking its place in the ring of light circling the walkway. Three release points, one shared current; the krathong you just made is now part of the festival everyone around you is watching.

The venue is the whole challenge. The OneSiam Skywalk is a four-pointed star with a circular opening cut through the middle, looking straight down on the Pathumwan junction — so the projection surface isn't a screen, it's the ring of deck around that hole, curving away in every direction. More than eight projectors were arranged around the circle to cover it, and the imagery had to be built so that from above it resolves into a clean ring of floating krathongs rather than a warped donut — the geometry that makes it beautiful is exactly what makes it hard. That play screen and the projection mapping were built in TouchDesigner by CHAYANON; the web app and a Rust realtime backend kept the ring in sync, streaming every new krathong onto the surface the instant a player hit send.

This was the bigger of the two Loy Krathong builds — a city event, with the BMA and a roster of partners behind it, run in one of the most visible spots in Bangkok. So it was built to hold a crowd and a curve at once: a Rust WebSocket server and Redis keeping the shared ring in sync at city scale, a maker that greets every visitor in Thai, English or 中文, and a projection geometry tuned for a circular deck instead of a flat wall. Across two nights it carried 3,567 players who floated 10,152 krathongs — a steady river of light circling the Pathumwan intersection, every krathong on it decorated by someone standing on the skywalk. Built under 27JUNE Studio, with the play screen and projection mapping by CHAYANON in TouchDesigner.