Radar Sweep Documentary — our demo

One example among many. Don't reuse its story, arc, shots, props or timings.

Demo: Catching the Moon 《狂風裡接住登月直播》 (52.0 s) · dark-documentary.mp4 · source in demo/

21 July 1969, Australian time: the 64-metre radio telescope at Parkes receives the TV of the Apollo 11 moonwalk in a storm. A calm English voice (Kokoro bm_lewis) tells it in eight sentences, with Chinese and English subtitles. Every date, time and number is quoted from CSIRO's account in demo/FACTS.md; the first step is told as it happened (the world saw it on Honeysuckle Creek's picture; Parkes's picture took over from 13:02:51).

Story & structure

The question the film keeps open: the observatory's director had said before the mission that the weather was their biggest weakness, and on the day a storm came. Will the dish hold?

Arc: a clear night while Parkes tracks Apollo 11 to the Moon (the scan reveals the dish; title) → a second scan rewrites the same shot into the stormy midday of 21 July → the dish is lowered to its own horizon, 29°38′, to wait for the Moon → two gusts over 110 km/h slam it against its gears (wind trace, alarm) → the comparison: wind force ten times what was considered safe → on the Moon, the TV camera switches on at 12:54 → the Earth–Moon view: three stations, and the first step goes out on Honeysuckle Creek's picture → the Parkes control room: the signal-strength needle jumps as the Moon enters the main beam → the monitor becomes the picture the world saw, HSK → PKS at 13:02:51 → the picture collapses into a line, the line becomes the scan, the camera pulls back from the whole dish in the wind: 2 h 31 min, about 600 million watching → the end card.

Native moves spent: the scan reveal and the sky behind the beam (opening), scan rewrites time (night → storm), scan wipes, motion echo (the tip and the gusts), radial pings, readouts written by the scan (angle, trace, ×10, source track, meter), scan line = TV raster, CRT to scan (into the last shot).

Shots

#	Time	Shot	Camera	Move / note
1	0–13.4	Black; the scan ignites at 0.2 and surges right on the beat; the dish is met at 1.1 (struck ring), keeps a cold rim; the Milky Way appears behind the beam; title 4.2–5.5; at 9.0 a second scan rewrites the shot into the storm (grey cloud deck, rain), erasing the night labels; `登月當天 · 21 JUL 1969 · STORM`	wide, dolly only (no rotation)	scan reveal; scan rewrites time
2	13.4–18.5	Side medium: the dish lowered from its tracking pose to 29°38′ with after-images; a large elevation reading counts down on an arc; `LIMIT 29°38′ · THE DISH'S OWN HORIZON`; `WAITING FOR THE MOON`	scan wipe in; slow orbit	motion echo
3a	18.5–21.6	Close on the feed legs and the focus cabin in the rain; wind trace top left, first gust over the 110 km/h line at 19.8	hard cut; handheld, shake grows with the wind
3b	21.6–24.2	Low wide from behind: second gust at 22.8, the dish slammed back (after-images, a flash); `WIND ALARM`	hard cut; strong shake
3c	24.2–27.6	Comparison panel over a dimmed close of the gear house: `CONSIDERED SAFE` one bar, `THE GUSTS, 21 JULY` ten bars, `×10 · 十倍風力`	locked	held 3 s; near-silence
4a	27.6–31.7	The Moon: the scan reveals the lunar module (gold-foil descent stage, four legs and pads, ladder, faceted ascent stage with triangular windows, docking hatch, thrusters, dishes) with long shadows under a low sun; Earth in the black sky; 30.45 `12:54:00 AEST · TV ON`, a warm signal line rises from the TV camera on the equipment bay to Earth	scan wipe in; low camera, slow push	a new space
4b	31.7–37.4	The Earth–Moon view, schematic: three stations with beams to the Moon; the source track `PICTURE THE WORLD SAW` (GDS/HSK, `12:56:20 FIRST STEP · VIA HSK`, cursor at `13:02:51 ?`) then a replay cursor that lights the beam on air; Parkes `OFF-AXIS ONLY: MOON STILL LOW`	scan wipe in; slow drift around the globe
5	37.4–40.7	The control room: desk, switch rows, the signal-strength meter, the central column, the small monitor at the far end, rain on the window; at 40.1 the needle jumps; a fast track past the column to the monitor	hard cut; hold, then a fast track
TV	40.7–45.35	Match cut: the monitor's screen grows into the picture the world saw (our drawing of a moonwalker by the lander), written line by line; noisy until 41.5, then clean: `SOURCE HSK → PKS · 13:02:51 AEST · PARKES · MAIN BEAM`; at 45.0 the picture collapses into a vertical line	match cut; locked	near-silence before the switch; the brightest chord on it
6	45.35–52	The line becomes the scan across the storm; the camera pulls back and up from the dish to about a third of the frame height, the dish buffeted (one more gust at 47.3 with after-images); a last radial ping at 45.7; `2 h 31 min · THE MOONWALK, HATCH TO HATCH`, `約 6 億人在看 · ≈ 600 MILLION PEOPLE WATCHING`; end card 48.0–52.0; the picture sinks to black from 50.6, the card stays	pull back and up	radial ping; end card

Voice and subtitles

Eight lines, Kokoro bm_lewis at speed 0.82 (about 2.6 words a second), each checked with core/tts/asr_check.py (asr overrides in demo/vo/lines.json for "Parkes", heard as "parks", and for numbers written as digits). Numbers are spelled out in the voice text and written as digits in the subtitles. Each cue starts 0.15 s before its line and ends 0.45 s after it, one Chinese line over one English line, bottom left; dark-documentary.srt is generated from the same timing.

Score structure

96 bpm, around D minor, one timeline (demo/mix.py):

Night: contrabass D2 and A2 held, bowed vibraphone open fifth under the title, four glockenspiel notes as the stars appear; one sonar ping per scan surge.
Storm: cellos D3 → F3 → E♭3 tightening, high violin tremolo; a timpani stroke, a deep hit, a metal groan and gear chatter on each gust; the alarm bell; wind and rain loud.
Comparison: almost silent.
The Moon and the globe: the storm drops away to a thin radio hiss; a quindar-like beep and a low carrier when the TV comes on; a vibraphone pulse in eighths that gets denser.
Control room: room tone and muffled wind; a click when the needle hits its stop; an air surge on the fast track.
The switch: TV hiss and line buzz, then near-silence, then the brightest chord (bowed vibraphone D major, violins, cellos, contrabass, a harp roll, glockenspiel).
End: the CRT's falling whine, the last ping, the chord breathes again, the suspended E resolves to D under the end card, everything lets go by 52 s.
Voice about 10 dB above the bed while it speaks; the bed is ducked and dipped 300 Hz–4 kHz under it. Master −14 LUFS, true peak −1.1 dBFS.

Palette & props

Echo blue-white #B3DBFF, scan white, text greys #EEF2F6 / #C4CED8 / #96A2B0, one warm accent #F2C48D for the Moon and the signal, warning red #FF8C78 for the over-limit values; storm cloud base up to #3B3F44.

Props, all built in code: the Parkes dish (lathe bowl, truss, feed tripod, focus cabin, tower, gear house, elevation gear sectors), terrain from noise, the lunar module, a wireframe Earth and Moon with coarse coastlines, the control room (desk, switches, meter, column, monitor, window), the TV picture (demo/tvart.js).

End card

48.0–52.0 s, bottom right of the last shot, written by the scan bar: Catching the Moon / 雷達掃描紀錄片 RADAR SWEEP DOCUMENTARY / LemoLab × Claude Opus 5.5 (28 px). It stays on the black after the picture sinks at 50.6 s.

Build notes

demo/
  build.sh        one command: fonts and voice (if missing) → speech check → readcheck → events → picture → mix → master → subtitles → poster, styleframe
  index.html      two WebGL canvases (the second only during scan wipes) and the 2D overlay; fonts
  main.js         render(t): timeline, VO, the Parkes world (terrain, dish, sky, rain), scans, cameras per shot, overlays, TV, end card, EV, TEXTS
  scenes2.js      the Moon (lander, Earth), the Earth–Moon globe, the control room; each with its own scan
  tvart.js        the TV picture (moonwalker, lander leg, ladder, regolith), drawn once at 960×720
  mix.py          wind, rain, foley, score and voice from events.json -> out/mix.wav
  vo/             lines.json (Kokoro bm_lewis, asr overrides) and the rendered clips with their durations
  tools/          fetch_fonts.sh (OFL fonts, Chinese subset from main.js), make_srt.py (subtitles from events.json)
  FACTS.md        every fact, its source and the quoted wording

sh demo/build.sh (24 fps, --workers 2; WORKERS=3 for more). On a fresh clone first run sh tools/fetch.sh voice, sh tools/fetch.sh instruments vsco2ce and sh tools/fetch.sh instruments vcsl; fonts are downloaded on the first run (the Chinese subset needs network access to the Google Fonts CSS API). After any change to Chinese text in main.js, delete demo/fonts/NotoSansSC-Light-subset.woff2 so it is fetched again.
About 60–110 ms a frame at 1080p on Apple silicon (2× supersampling, bloom); scan-wipe frames render two views.
render(t) depends on t only: scans, gusts, the dish pose, the wind and rain offsets are closed-form.
?t0=&t1= renders a cut of the timeline; &sign=1 adds the signature line over the last 2.5 s of a cut.
Demo-specific pitfalls: the star shot keeps the camera unrotated; the scan front is faded near the lens on the Moon; the lunar module casts its shadows by projecting each solid part onto the ground along the sun direction; the TV readout sits on a dark plate because the ladder in the picture crosses it.