Understanding the 'Boil' Effect in Animation: A Guide for Creators
Line boil is the small variation in a drawn outline from frame to frame. A shape can appear to shimmer even when its overall pose is held. A digital paper wiggle can suggest the same handmade energy, but moving an entire cutout and redrawing its outline are different effects.
Line boil, paper wiggle, and stop motion
In a redrawn sequence, the contour changes between drawings. In a paper-cutout workflow, the same silhouette may instead shift or rotate slightly between frames. Both create visible variation, but a stable contour moving around is not evidence that its lines were redrawn.
| Effect | What changes | Useful starting point |
|---|---|---|
| Line boil | The outline itself varies between drawings | Illustration or hand-drawn character work |
| Paper boil in this editor | The whole cutout shifts and rotates | A restrained handmade wiggle around a photo |
| Stop motion in this editor | The cutout moves in discrete position and rotation steps | A visibly stepped collage movement |
What Paper Animation actually changes
The current paper editor uses repeating offsets to move the cutout horizontally and vertically, with a small rotation. Intensity controls the amount of movement and Speed changes its timing. Paper boil does not animate fractal noise around the silhouette or generate newly drawn contours.
Border Roughness shapes the torn edge, while the texture controls add a surface treatment. Those settings change the appearance of the asset. They do not determine how often a new drawing is displayed. The Stop motion preset uses separate stepped offsets, which gives it a different rhythm from the continuous Paper boil movement.
Build a restrained paper wiggle
- Select a clear subject: upload a photo, click the subject, and inspect the mask before styling.
- Set the edge: start with a narrow border and modest roughness. Increase either only if the silhouette stays readable.
- Choose Paper boil: start with Intensity around 5 to 10 and Speed at 1.0×. These are suggested starting values, not a universal preset.
- Leave margin: reduce the cutout size or center it if the moving border touches the frame.
- Compare Still: switch motion off briefly. If the animated version distracts from a face, logo, or title, reduce the intensity.
The current Speed control ranges from 0.5× to 2.0×. It changes the animation rhythm, not the export frame rate. Export choices of 24, 30, and 60 FPS are separate settings.
When the effect looks wrong
- The subject drifts too far: lower Intensity and leave more canvas margin.
- Fine text becomes tiring to read: use Still or animate a background layer instead.
- The outline looks damaged: check the mask and lower Roughness before changing motion.
- You want redrawn lines: create alternate drawings in an illustration or animation program. This preset does not redraw the artwork.
Export a test before using it as an overlay
Use a short 720p video first. Transparent video uses WebM where supported; choose a solid or green-screen background when the next app cannot preserve alpha. A PNG is a single still frame, so it will not carry the wiggle into a video editor.
For an intentionally stepped look, follow the stop-motion workflow. For the full photo-to-cutout process, see the paper cutout tutorial.