This is for animators who need to think about depth, not just flat movement across the screen. It connects all 12 animation principles to three-dimensional space: arcs that curve through depth, squash and stretch that maintains volume in all directions, staging that uses foreground and background layers. The checklist alone is worth it (Where is the floor? What overlaps what? Where is the light source?). Use this when your animation feels flat or when characters seem disconnected from their environment. The core idea is simple but easy to forget: the screen is a window into 3D space, not a canvas you're decorating.
npx skills add https://github.com/dylantarre/animation-principles --skill spatial-thinking