cycle-atlas/.agents/skills/hyperframes-animation/rules/waterfall-entry.md

name, description, metadata

name	description	metadata
waterfall-entry	Staggered ARRIVAL cascade — words/elements whip in from below (one consistent direction), each starting before the previous settles, an accelerating wave that resolves into a composed layout. Title cards, segment openers, list/feature intros. Opacity is BINARY 0→1 via tl.set — never fade an arrival.	tags entrance, cascade, stagger, kinetic-text, title-card, segment-opener, arrival, waterfall, whip

Waterfall Entry

Staggered ARRIVAL cascade: words/elements whip in from below (one consistent direction), each starting before the previous settles — an accelerating wave that resolves into a composed layout. Title cards, segment openers, list/feature intros.

This is an in-scene arrival, not a seam. Its seam sibling is the waterfall CUT (cut-the-curve doctrine skill, seams/waterfall-cut.md); do not mix their rules:

	Entry (this rule — arrival)	Waterfall Cut (seam)
Opacity	BINARY 0→1 via tl.set at entry — never fade	ignites at 0.35 mid-path — the fade IS the velocity trick
Axis default	Y, from below	X, riding the current
Outgoing side	none	words ramp out on mirrored power4.in

Choreography

• Overlap, don't queue — next element starts within ±2 frames of the previous settling; gaps SHRINK across the cascade; the last element snaps.
• Velocity varies by weight — heavy/anchor elements travel further and longer; light words/punctuation snap in tight:

Parameter	Anchor/heavy	Normal word	Light/punctuation
Y offset	60–80px	40–50px	30–48px
Duration	0.16–0.20s	0.13–0.16s	0.10–0.13s
Overlap	0–2f gap	1f overlap	1–2f overlap

• Ease power4.out (expo.out for extra snap); never .inOut on an entry.
• One direction per cascade.
• Split the FINAL word into fragments to extend the climax; fragments travel further.
• Post-settle, the group usually slides to make room for the next beat — that's nudge-curve.md.

JS

Each element: tl.set (instant reveal + offset) then tl.to (whip to rest). nextStart = prevStart + prevDuration − (overlapFrames × F); +overlap = cascade, −overlap = deliberate gap. CSS: elements start opacity: 0; display: inline-block.

var F = 1 / 60;
var t0 = 0.1;
// anchor (heaviest): biggest travel, longest settle
tl.set("#el-1", { opacity: 1, y: 80 }, t0);
tl.to("#el-1", { y: 0, duration: 0.18, ease: "power4.out" }, t0);
// normal word: 2 frames after the anchor finishes
var t1 = t0 + 0.18 + 2 * F;
tl.set("#el-2", { opacity: 1, y: 45 }, t1);
tl.to("#el-2", { y: 0, duration: 0.15, ease: "power4.out" }, t1);
// light word: 1 frame BEFORE the previous finishes (overlap)
var t2 = t1 + 0.15 - F;
tl.set("#el-3", { opacity: 1, y: 40 }, t2);
tl.to("#el-3", { y: 0, duration: 0.14, ease: "power4.out" }, t2);
// split final-word fragments: tightest overlap, extra travel (lighter)
var t3 = t2 + 0.14 - F;
tl.set("#frag-a", { opacity: 1, y: 70 }, t3);
tl.to("#frag-a", { y: 0, duration: 0.16, ease: "power4.out" }, t3);
var t4 = t3 + 0.14 - F;
tl.set("#frag-b", { opacity: 1, y: 70 }, t4);
tl.to("#frag-b", { y: 0, duration: 0.15, ease: "power4.out" }, t4);
// punctuation: lightest, fastest
var t5 = t4 + 0.13 - 2 * F;
tl.set("#dot", { opacity: 1, y: 48 }, t5);
tl.to("#dot", { y: 0, duration: 0.12, ease: "power4.out" }, t5);

Anti-patterns

Don't	Instead
Queued entries (each waits for the previous to settle)	Overlap ±1–2 frames — the cascade is a wave, not a queue
Same offset/duration for every cascade element	Vary by weight: anchors travel further, punctuation snaps
Gradual opacity fade on an arrival	Binary 0→1 via tl.set — fading fights the snap (seam cuts fade; arrivals don't)