Blur
The Blur shader softens the canvas image using one of four blur algorithms. It uses a 2-pass rendering pipeline for separable blur types (Gaussian, Box) and specialized single-pass techniques for Radial and Zoom.
Parameters
Type
| Value | Effect |
|---|---|
| Gaussian | Classic smooth blur with bell-curve falloff (default) |
| Box | Uniform averaging — each pixel samples equally from neighbors |
| Radial | Circular blur radiating from a center point, simulating rotational motion |
| Zoom | Directional blur radiating outward from center, simulating camera zoom |
Radius
| Range | Default | Step |
|---|---|---|
| 0–100 | 10 | 1 |
The blur kernel size in pixels. Larger values produce stronger blur.
| Radius | Gaussian/Box | Radial | Zoom |
|---|---|---|---|
| 1–5 | Subtle softening | Slight rotational smear | Minimal zoom streaks |
| 10–30 | Moderate blur | Noticeable spin | Visible zoom lines |
| 50–100 | Heavy blur | Strong circular motion | Dramatic zoom effect |
Center X / Center Y
| Range | Default | Step |
|---|---|---|
| 0–1 | 0.5 | 0.1 |
The center point for Radial and Zoom blur types, expressed as a fraction of canvas size:
| Value | Position |
|---|---|
| 0, 0 | Top-left corner |
| 0.5, 0.5 | Center (default) |
| 1, 1 | Bottom-right corner |
Info
Center X and Center Y only affect Radial and Zoom blur types. They have no effect on Gaussian or Box blur.
Keyframing
- Type uses hold interpolation — snaps between blur modes
- Radius, Center X, Center Y use numeric interpolation
Animation Ideas
- Keyframe radius from 0 to 50 for a focus-pull effect
- Animate center position for a moving focal point
- Combine zoom blur with increasing radius for a warp-speed transition
Use Cases
- Depth of field — Gaussian blur at moderate radius (10–20)
- Dream sequence — Large Gaussian blur (30+) at low-to-moderate radius
- Speed lines — Zoom blur from center, radius 20–40
- Spinning transition — Radial blur with animated radius
- Tilt-shift — Low Gaussian blur for miniature effect
- Background softening — Apply during specific timeline sections when foreground action is the focus
Technical Notes
- Gaussian and Box use a 2-pass separable pipeline: horizontal blur → vertical blur. This is significantly faster than a single-pass 2D kernel
- Radial blur uses 129 samples (64 per side) along circular arcs from the center point for high-quality results
- Zoom blur samples along radial lines from the center point outward
- Center coordinates are normalized (0–1) and mapped to actual pixel positions at render time