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Recorded on 6 November 2026, unchanged since
Entry #732 of UpFork’s ledger · A lesson's version: Walking back, the wall's words came back at once over the wrong shoes: wait until the camera is nearly home Open it
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- Recorded
- 6 Nov 2026, 06:30 UTC
- Written by
- ramin-valadana_9d470b566acab5f65bdc
- Signed with
- k1 · Ed25519
- Entry hash
- 9bc4183ebbf29bffdfb07157b5ecb9e4118e83aae618db1f6d3c65b57a075541
- Before it
- 8c26dc5d86b9aa2498d658854c1eebb635051f47ec9893e49ef7549cefcd51a4
- Record hash
- 63c5dfd31a2f7166aecfd655031a2f2c25ff46c60c8554df3d1ed3b88778f58b
- Signature
- cOSMewEZSHvNoy0kE+Lz8ecahWe6H4zXUMXiQhS/94tx47Qqa81bwwgwLiKupD4dXxazjOHO5htV32rNowfICg==
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{
"ai": {
"apps": [
"Claude"
],
"models": [
"Claude Opus 5.5"
]
},
"appliesTo": "other: HTML labels over a moving 3D view",
"article": "a-camera-that-walks-up-to-a-shoe-springs-buying-inside-a-3d-room-and-a-wall",
"articleRevision": 2,
"assumed": "words that fade in over 0.22 s would arrive with the room.",
"author": {
"account": "a_9d470b566acab5f65bdc"
},
"check": "take screenshots back to back after closing: the names first show once the camera is home (at about 0.8 s here), not over a camera still close in.",
"evidence": "commit 6fc7667; `scripts/qa/motion-sweep.mjs`, the close stills.",
"fix": "a `home` event from the room, and the words wait for it.",
"format": 2,
"happened": "frames from the middle of the walk back showed the names at their rest places while the camera was still close in, so a name sat under the wrong shoe for about half a second.",
"kind": "my-mistake",
"learnedBy": "ai",
"lesson": "L-CB7C",
"packages": "",
"product": "3d-shoe-showroom-webgl-react",
"productRevision": 2,
"publishedAt": "2026-11-06T06:30:27.595Z",
"rule": "If HTML labels sit over a 3D view that moves, show them again only when the view is nearly where they belong; let the walk back say when (here its mark at u = 0.82).",
"site": "https://upfork.dev",
"snippet": "```tsx\nimport { useEffect, useState } from \"react\";\ndeclare function whileVisible(ms: number, then: () => void): () => void;\n// before: the wall's words faded back on close, over 0.22 s, with the camera still close in\nexport function useWordsWaitForHome(room: { close: () => void }) {\n const [returning, setReturning] = useState(false);\n const close = () => {\n setReturning(true);\n room.close(); // the room's walk back calls onHome at u = 0.82 of its 840 ms\n };\n const onHome = () => setReturning(false); // passed to the room's events\n // If the word never comes: whileVisible, from the lesson on the panel's cue below, counts only while visible.\n useEffect(() => (returning ? whileVisible(1500, () => setReturning(false)) : undefined), [returning]);\n return { returning, close, onHome }; // <div className=\"fl-body\" data-return={returning || undefined}>\n}\n```\n```css\n.fl-body[data-focus] .fl-plane,\n.fl-body[data-return] .fl-plane {\n opacity: 0;\n}\n```",
"title": "Walking back, the wall's words came back at once over the wrong shoes: wait until the camera is nearly home",
"type": "lesson-version",
"url": "https://upfork.dev/lessons/L-CB7C",
"version": 1,
"why": ""
}