heygen-com--hyperframes/skills/hyperframes-animation/rules/kinetic-beat-slam.md

name, description, metadata

name	description	metadata
kinetic-beat-slam	Percussive kinetic typography — short phrases slam in on a steady beat with distinct per-phrase entrances, optional rhythm chrome (metronome ticks, beat bar), then a locked finale.	tags text, kinetic, typography, beat, rhythm, slam, percussive, punchy

Kinetic Beat Slam

Short phrases hit one at a time on a steady beat, each with a different entrance, then stack into a locked finale. This is the recipe for "punchy / rhythmic" text-forward pieces (taglines, manifestos, hype intros). The difference between generic and rhythmic is (1) one shared onset array driving every element, (2) distinct entrances per phrase rather than one reused helper, and (3) optional rhythm chrome that visibly keeps the beat.

How It Works

1. Define the beat once. A single BEATS = [t0, t1, t2, …] array (seconds) is the rhythmic spine. Every phrase entrance, accent, and chrome tick reads its time from this array — so the whole piece locks to one pulse instead of drifting hand-tuned offsets.
2. Vary the entrances. Phrase 1 slams (scale + blur), phrase 2 snaps from the side, phrase 3 rises and rotates. Same energy, different form — reusing one punchIn() for all three reads as flat.
3. Land a finale. All phrases lock into a left-aligned or centered stack; an accent underline sweeps in; optionally a continuous low-amplitude pulse holds the last beat.

Beat & Easing

Pick the entrance easing by attack character (the choice is discrete):

GSAP ease	Attack feel
power4.out	Hard slam, fast settle ⭐ default for a hit
expo.out	Hardest snap (side-snaps, whip-ins)
back.out(2)	Overshoot pop — accents, not body words
circ.out	Heavy rise with momentum

Use at least 3 distinct easings across the piece (entrances are its "tone of voice"). Keep durations short — 0.35–0.6s on the hit, ≤0.25s on the exit — so the beat stays percussive.

HTML

<section class="clip" data-start="0" data-duration="15" data-track-index="1">
  <div class="kbs-stage">
    <div class="kbs-line" id="p1"><span class="verb">Notice</span> more.</div>
    <div class="kbs-line" id="p2"><span class="verb">Decide</span> faster.</div>
    <div class="kbs-line" id="p3"><span class="verb">Act</span> now.</div>
  </div>
  <!-- optional rhythm chrome -->
  <div class="kbs-metronome" aria-hidden="true"><i></i><i></i><i></i><i></i><i></i></div>
</section>

CSS

.kbs-stage {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 8px;
  padding: 120px 160px; /* title-safe margin */
  box-sizing: border-box;
}
.kbs-line {
  font-family: "Archivo Black", "League Gothic", sans-serif; /* embedded display face */
  font-size: 150px;
  line-height: 0.96;
  letter-spacing: -0.03em;
  color: #f5f5f5;
  will-change: transform, filter, opacity;
}
.kbs-line .verb {
  color: #ff5b2e;
} /* one accent hue */
.kbs-metronome {
  position: absolute;
  bottom: 64px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 14px;
}
.kbs-metronome i {
  width: 6px;
  height: 28px;
  background: #ff5b2e;
  opacity: 0.25;
}

GSAP Timeline

<script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
<script>
  window.__timelines = window.__timelines || {};
  const tl = gsap.timeline({ paused: true });

  // ONE tempo grid drives everything — phrases AND the metronome read it (no scattered offsets).
  const PULSE = 0.4; // seconds per sub-beat (the grid)
  const BEATS = [PULSE * 1, PULSE * 5, PULSE * 9]; // phrase onsets, on the grid

  // Distinct entrances per phrase (NOT one reused helper).
  tl.fromTo(
    "#p1",
    { scale: 1.5, filter: "blur(16px)", opacity: 0 },
    { scale: 1, filter: "blur(0px)", opacity: 1, duration: 0.5, ease: "power4.out" },
    BEATS[0],
  );
  tl.fromTo(
    "#p2",
    { x: -320, opacity: 0 },
    { x: 0, opacity: 1, duration: 0.45, ease: "expo.out" },
    BEATS[1],
  );
  tl.fromTo(
    "#p3",
    { y: 90, rotation: 6, opacity: 0 },
    { y: 0, rotation: 0, opacity: 1, duration: 0.55, ease: "circ.out" },
    BEATS[2],
  );

  // Rhythm chrome: each metronome tick flashes on the SAME grid (PULSE), not a magic offset.
  const ticks = gsap.utils.toArray(".kbs-metronome i");
  ticks.forEach((tick, i) => {
    tl.to(
      tick,
      { opacity: 1, duration: 0.08, yoyo: true, repeat: 1, ease: "none" },
      PULSE * (i + 1),
    );
  });

  // Finale hold: a low-amplitude breath on the locked stack.
  // floor (not ceil) so the repeat never overshoots data-duration; max(0,…) so a short hold
  // never yields a negative repeat (GSAP treats negative repeat as -1 = infinite = non-deterministic).
  const holdStart = BEATS[2] + 0.7,
    cycle = 1.6,
    holdDur = 15 - holdStart;
  tl.to(
    ".kbs-stage",
    {
      scale: 1.01,
      duration: cycle / 2,
      ease: "sine.inOut",
      yoyo: true,
      repeat: Math.max(0, Math.floor(holdDur / cycle) - 1),
    },
    holdStart,
  );

  window.__timelines["main"] = tl;
</script>

How to Choose Values

• BEATS spacing — 1.2–1.8s between hits reads as a confident beat; <0.8s feels frantic, >2.5s loses the pulse. Keep spacing even (it's a beat).
• Entrance duration — 0.35–0.6s. The hit must resolve before the next beat.
• Distinct entrances — assign a different transform axis per phrase (scale / x / y+rotate). Reuse the ease family, vary the motion.
• Accent hue — exactly one (the verbs). The rest is mono white/near-black.
• Rhythm chrome — optional but high-impact for "rhythmic": a 5-tick metronome, a center beat bar, or a // label monospace tag pulsing on-beat. Mark any decorative that must survive a shader transition per ../../transitions/overview.md rules.

Key Principles

• One beat array, not scattered offsets — every element times off BEATS[]. This is the single biggest lever for "rhythmic."
• Different entrance per phrase — a reused punchIn() for all lines is the flat-but-competent tell.
• Short attacks — percussive means fast in, brief, decisive. Long fades kill the beat.
• One accent hue, heavy weight — embedded display faces (Archivo Black, League Gothic, Oswald) at 150px+; see hyperframes-creative/references/typography.md.
• Finale earns the hold — stack + underline sweep + optional breath; don't just leave the last phrase sitting.

Critical Constraints

• Timeline paused: gsap.timeline({ paused: true }). Never tl.play().
• No infinite repeats on the hold/chrome — use repeat: Math.max(0, Math.floor(dur / cycle) - 1) (no repeat: -1). Use Math.floor, not Math.ceil — ceil overshoots data-duration and trips the gsap_repeat_ceil_overshoot lint rule; the Math.max(0, …) guards against a negative repeat (which GSAP reads as -1 = infinite = non-deterministic) when the hold is shorter than two cycles.
• No banned exit animations between scenes — if this is one of several scenes, the transition is the exit (see ../../transitions/overview.md); only a final scene may fade out.
• Display font must be embedded or it silently falls back at render (Anton/Bebas-as-literal are NOT embedded — Bebas Neue aliases to League Gothic; verify in typography.md).
• Registry key = data-composition-id on the root.

Combinations

• 3d-text-depth-layers.md — extruded depth on the slammed words
• css-marker-patterns.md — underline sweep / circle on the finale
• sine-wave-loop.md — the finale breath/pulse

Pairs with HF skills

• /hyperframes-animation — timeline + easing vocabulary (../../adapters/gsap-easing-and-stagger.md)
• /hyperframes-creative — references/video-composition.md (foreground rhythm chrome), references/typography.md (embedded display fonts)
• /hyperframes-core — composition wiring, determinism (finite repeats)