# Glacier Calving Day

- Collected by: petergpt (collection) (original author unknown)
- Card: Verified rebuild
- Theme: Simulations
- Stack: Three.js CDN · three@0.170.0
- Interaction: Drag
- Licence: prompt is a credited link (Shared publicly by the author; full text with credit, removed on request); rebuild code MIT
- Verified: 2026-11-09
- Original post: https://github.com/petergpt/3d-prompt-collection/blob/HEAD/README.md#prompt-54

## Original prompt

```text
Create a monumental Three.js scene of the Perito Moreno glacier front: a sixty-meter wall of fractured blue ice stretching across a milky turquoise lake, boardwalk crowds waiting on the peninsula, tour boats holding respectful distance — and on command, a tower of ice peels away and collapses in slow majesty. Open directly on the full face glittering in sun, small falls of ice dust already trickling, anticipation built in. No title screen, menu, loading state, or empty lake.

If you use Three.js, add an import map before the module script mapping "three" and "three/addons/" to the same pinned version, and import only via those names. Everything procedural; no external image assets or models.

Single idea: the patience and violence of ice — a living wall that breaks on your command and makes the whole lake answer.

#### THE WALL
- Build the face with real glacial character: vertical fracture columns and seracs, deep crevasse shadows glowing impossible blue, white sun-bitten crests, meltwater streaks, arch hollows at the waterline. The wall must reward close inspection like architecture.
- Behind it, the glacier back stretches up-valley as a rumpled white river between dark Patagonian peaks.

#### THE CALVING
- One simple trigger: Calve — a chosen tower groans, sheds dust, leans and peels off in convincing large rigid fragments, plunging with a white eruption, then bobbing up as fresh blue bergs.
- The lake answers: a radial wave rolls out, rocks the tour boats visibly, slaps the shoreline; gulls burst off the water; brash ice spreads and drifts in the current.
- A replay scrub for the last collapse lets the viewer relive it in slow motion; each trigger varies the tower and break pattern.

#### THE PATAGONIAN STAGE
- Complete the place: layered boardwalks with small crowds that visibly react, southern beech forest in autumn rust and green, distant snow peaks, condors circling, lake water in glacial milk-turquoise with floating bergs of varied age.
- Crisp high-latitude sunlight, brilliant whites and blues, dramatic but never gloomy.

#### SIMPLE EXPLORATION
- Orbit, pan, zoom; reset to the hero head-on panorama of the wall. Presets: boardwalk crowd view, boat-deck view rocking on the wave, waterline view along the face, and a high aerial of glacier and lake.
- Controls: the calve trigger, replay scrub, and a sunlight-angle slider. Nothing else. Tiny HUD: height of the wall marker for scale. Compact collapsible UI.

#### PERFORMANCE DISCIPLINE
- Pre-fractured fragment pools for the collapse, instanced bergs and trees and crowds, budgeted spray, devicePixelRatio clamped to 2, quality selector thinning far valley before the wall face. Smooth on a modern laptop.
```

Known issue: In the distant opening shot the deep crevasses still read as fairly evenly spaced blue lines, and close up the large white faces look slightly blotchy.

Prompt collected by petergpt; original author unknown (https://github.com/petergpt/3d-prompt-collection/blob/HEAD/README.md#prompt-54) via 3dmotion.io/e/glacier-calving-day