This one's for when you need animations that feel dimensionally correct, not just moving flat shapes around the screen. It enforces the principle that objects should maintain consistent volume and perspective through motion, whether you're rotating a UI card with proper vanishing points or ensuring a character's head doesn't accidentally grow during a turn. The construction approach is solid: define the 3D form and center of mass first, then animate with that spatial model in mind. Most useful when your transforms feel "off" and you can't figure out why. It's usually a solid drawing violation like flat rotation instead of perspective, broken weight distribution, or inconsistent scale.
npx skills add https://github.com/dylantarre/animation-principles --skill solid-drawing-mastery