Springs and damping: a smooth camera and soft motion

A camera eases after the hero. A gun kicks when it fires and settles back. A car rocks over bumps, and a character’s tail lags behind a turn. All of this runs on one pair of ideas: a spring pulls toward a target, and damping stops the swinging. This page explains why a spring swings along a sine and what the damping modes are. It shows why a spring beats smoothing for a camera, how to tune one with numbers that make sense, and why a stiff spring in a game sometimes blows up.

Why this matters

In the lesson on smoothing, the camera covered a fraction of the distance to the hero every frame. It does catch up, but it starts at full speed right away, and it has no inertia to carry it past the target. A spring remembers its velocity, so its motion is smooth at the start and at the end. Springs are everywhere in games: cameras, recoil, vehicle suspension, wobbling interface elements, hair. Learn two knobs, frequency and damping, and you can tune any of them. You will also see why something shakes, lags or flies off.

Further in the article

1. The farther you stretch a spring, the harder it pulls
2. Damping makes the swinging die out
3. Why a camera needs a spring, not smoothing
4. Where springs appear in games
5. Stability: when a spring blows up
6. In engines and Blender
7. Where it breaks
8. Connections: the same idea in other fields
9. Key points
10. Test yourself