This one teaches you the physics behind why good animation feels natural instead of robotic. It breaks down easing curves (ease in, ease out, linear) and gives you the 80/20 rule: use ease out for 80% of UI animations because fast starts communicate responsiveness. The spacing principle is clearly explained, traditional animation concepts map to digital bezier curves, and there are specific recommendations for buttons, modals, character jumps, and camera movement. The domain applications section is genuinely useful because it tells you which easing to use where and why. If your animations feel lifeless or you're just guessing at curve values, this gives you the underlying theory to make intentional choices.
npx skills add https://github.com/dylantarre/animation-principles --skill slow-in-out-mastery