Jiggle
A spring that chases the layer the whole way — lag, overshoot, wobble to rest.
Jiggle attaches a spring between where the layer is meant to be and where it actually draws. While the layer moves the spring drags behind. When the layer stops the spring overshoots and wobbles down to rest.
The difference from Inertia is that Jiggle reacts to all motion, continuously — not just to keyframes. A layer driven by Oscillate, moving along a path, or following a parent will all make it wobble.
When to reach for it#
- Jelly and soft-body feel on anything that moves.
- Antennae, tails, hair, and other trailing appendages.
- Softening motion that comes from a path or a driver, where Inertia has no keyframes to grab.
How it works#
It is a damped spring, integrated forward from time zero at a fixed 60 steps per second. Fixed-step integration is why it is deterministic — scrubbing to 4 seconds gives the same answer as playing to 4 seconds, and the export matches the preview.
That also means the cost grows with the timeline position: evaluating at 60 seconds runs 3,600 steps. It is capped at two minutes of timeline, which is well past where anyone would notice.
Parameters#
The spring's natural frequency in hertz. Higher is tighter and faster to catch up. Low stiffness with low damping is jelly; high stiffness with high damping is barely noticeable.
How quickly the wobble dies, as a ratio. 0.1 wobbles for a long time. 1.0 is critically damped — it catches up without overshooting at all, which is a nice lag with no bounce.
Blends between no spring and full spring. 0.5 gives you half the lag and half the overshoot, which is the easiest way to dial an effect back without retuning the physics.
Which property the spring chases. Rotation on a trailing element gives you a whip; position gives you drag.
Recipes#
A trailing antenna
- Parent the antenna to the body.
- Add Jiggle on Rotation, Stiffness 2.5, Damping 0.15, Amount 1.
- Add Pivot Offset so the antenna rotates from its base, not its middle.
The pivot matters more than the spring numbers here. A perfectly tuned spring rotating around the middle still looks wrong.
Things that catch people out#
Below about 0.05 the wobble outlasts most compositions. If the layer never comes to rest, raise damping before touching anything else.
The spring re-integrates from zero on every evaluation, so a jiggling layer at 50 seconds does more work than at 2 seconds. Not usually noticeable, but worth knowing if a long comp with many jiggling layers slows down toward the end.
See also#
Something here wrong or missing? Tell us in the community.