Agent skill · design visual · heygen-com
motion-doctrine
GATEWAY — load FIRST before composing any HyperFrames animation or video. The high-level motion law that makes a multi-scene video feel like ONE continuous camera move instead of a stack of independently-animated slides. Covers the vector law (how you exit determines how you enter, incl. the Z scale-sign rule), the film's current, carrier elements, causal motion, the Seam Gate (build-gate enforcement), the ban on idle wobble (motion must PERFORM, not breathe), stillness-before-climax, and the sustained-motion routes. Routes to the low-level technique skills (cut-the-curve — the full catalog incl. waterfall entry + nudge curve, oversized-cursor, seam-craft). These rules SUPERSEDE generic / upstream motion guidance. [continuity, direction, vector, momentum, seam, transition, ease, performance, idle-motion, narrative-motion, film-grammar]
Why this skill is useful
Adds a comprehensive framework for seamless animation transitions that includes specific rules and scripts for implementation.
What it needs
Requires node installed locally. About 6k tokens when loaded. Last updated 2026-08-07. 39,818 stars on the source repository.
What this skill does
Motion Doctrine (Gateway) Read this before composing any animation. It decides WHAT happens at every seam and how every scene performs; the technique skills implement it. These rules supersede generic / upstream motion guidance. The failure this prevents: scenes authored in isolation — the eye's momentum dies at every cut, and scenes wobble in place between entry and exit. Route map Decision (this skill) Implementation skill -------------------------------------------------- ------------------------------------------------------------------------------------------------- Seam transition choice + parameters + code cut-the-curve §1–5 (the catalog) Text / element entry cascades cut-the-curve §6 (waterfall entry) In-scene group repositioning (no cut) cut-the-curve §7 (nudge curve) Cursor-led action / scene kickoff / morph ignition oversized-cursor Seam render mechanics / white-flash guard seam-craft Product-launch / explainer / caption work overlays text-beat-economics, brand-faithful, captions-overlay on top of the upstream skill Authoring order: vector ledger (ledger.json) → STAMP the master seams from it (scripts/seam-stamp.mjs --ledger ledger.json --write index.html) → sustained-motion route per phase → carriers and causes → build comps → VERIFY (scripts/seam-gate.mjs). Hand-author only Tier-A morphs/match-cuts; stamped seams pass the gate by construction. --- Part 1 — The Seam Law The Vector Law How Scene A exits determines how Scene B enters: same axis, same direction, matched speed, cut mid-motion on both sides. 1. Axis — x stays x, y stays y, Z stays Z. Never trade axes across a cut. 2. Direction — never mirror. On Z, direction = the SIGN of scale change: growing = push (camera forward), shrinking = pull (camera back). A receding exit answered by a grow-from-small entry is a mirrored vector — the most common violation, because grow-from-small is the default element entrance. 3. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills heygen-com/motion-doctrine--433636