The jittering you're experiencing is likely due to how Spine's physics system works at a fixed time step.
Understanding the Issue
Spine's physics runs at a fixed update rate (controlled by the FPS setting on the physics constraint, which defaults to 60). When your application renders faster than the physics update rate, you can see the skeleton movement before physics catches up, causing visible jitter. This is especially noticeable when bones are moving quickly, like in your up-and-down animation.
Solutions to Try
Adjust the Physics FPS Setting
- Select your physics constraint in the tree
- Look for the
FPS setting in the Setup section
- Try increasing it to match or exceed your application/editor frame rate
- Note: Changing this will affect physics behavior, so you may need to readjust other physics settings (Inertia, Strength, Damping, etc.) to get the look you want
Reduce Movement Speed
- The faster the bone moves, the more noticeable the lag between physics updates becomes
- Try slowing down your up-and-down animation to see if the jitter reduces
Adjust Physics Strength
- If the
Strength value is too high, the physics will apply a strong corrective force each time it catches up, making the jitter more pronounced
- Try reducing the Strength value to make the transitions smoother
Experiment with Other Physics Settings
- Adjust
Damping to reduce oscillation from large movements
- Fine-tune
Inertia to control how much the bone lags behind
The key is finding the right balance between your animation speed, physics FPS, and the constraint settings to achieve smooth motion.
