Arc Mastery

This one teaches Claude about motion arcs, the animation principle that keeps things from looking robotic. It covers why natural movement follows curves (joints rotate, gravity creates parabolas), different arc types from simple circular to complex S-curves, and how to apply them across UI transitions, character animation, and motion graphics. The practical bits are solid: add control points perpendicular to straight paths, use 10-20% of travel distance for subtle arcs, verify readability from camera angle in 3D. Worth having if you're doing any animation work where you need Claude to understand why a button shouldn't just slide in linearly or why a character's hand needs to follow a curve even when pointing straight.

skills.sh installs: 578
GitHub stars: 146
last updated: Aug 21, 2026

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Install

$ npx -y skills add dylantarre/animation-principles --skill arc-mastery --agent claude-code

Installs into .claude/skills of the current project.

Files

Arc Mastery

The Natural Path Principle

Almost all natural movement follows curved paths. Arms swing in arcs. Heads turn on arcs. Thrown objects travel parabolic arcs. When animation moves in straight lines, it immediately feels mechanical and artificial. Arcs are the signature of organic motion.

Core Theory

Anatomical basis: Bodies are systems of hinges and pivots. When a joint rotates, everything attached to it moves in an arc centered on that joint. Straight lines require mechanical rails—biology doesn't have those.

Physics basis: Gravity creates parabolic curves on projectiles. Momentum creates curved paths when direction changes. Straight-line direction changes require infinite force.

Arc Types

Circular arcs: Pure rotation around a single pivot (pendulum, door swing) Parabolic arcs: Projectile motion under gravity (jumps, throws) S-curves: Complex motion through multiple pivots (whip crack, spine movement) Figure-8 patterns: Continuous flowing motion (hips during walk, flowing cloth)