Motion
Natural physics
Things ease, travel in arcs, and only overshoot when they arrive with momentum.
Takeaways
- Slow in, slow out on every body.
- Arcs, not straight lines.
- Weight classes set duration and overshoot.
- A bounce needs momentum.
What it means
Real objects do not start and stop instantly or travel in straight lines. They ease in and out, follow curved paths, and a heavy thing barely bounces while a light thrown thing may. Overshoot without travel just looks like a wobble.
In a RasanAI film
Heavy panels get no overshoot and a longer duration; medium things 3 to 5 percent; light chips up to 15 percent, and only when thrown. Moves ease at both ends, and bodies are never linear.
Origins and sources
Disney's twelve principles of animation (Johnston and Thomas, The Illusion of Life): slow in and slow out, arcs, squash and stretch, follow-through.