Blur

Applies an anisotropic gaussian blur with independent X and Y radii, quality tiers, and edge handling modes.

Category: Effects Menu path: Effects > Blur

Ports

Port	Type	Direction	Description
in	imageRgba16f	input	Input image
blur_map	imageRgba16f	input	Optional per-pixel blur intensity map (luminance-driven)
out	imageRgba16f	output	Blurred result

Parameters

Param	Type	Default	Description
blur	vec2	(10, 10)	Blur radius in pixels. X and Y are independent (linked by default). Keyframeable.
invertBlurMap	boolean	false	Invert the blur map so dark areas get more blur instead of bright areas.
quality	enum	Normal	Blur sampling quality tier. Options: Draft, Normal, High.
edgeMode	enum	Clamp	How to handle pixels near the image edge. Options: Clamp, Transparent.

Expose Channels

When enabled (E button on node header), adds input ports that override params via edge connections:

Port	Type	Overrides
blur_in	vec2	blur

How It Works

The blur is a separable gaussian applied in two passes (horizontal then vertical), which is significantly faster than a 2D convolution. Each axis can have a different radius, so you can create directional blurs by setting one axis to zero. For large radii, the engine builds a downsample pyramid to keep performance consistent regardless of blur size.

The blur map input modulates the blur radius per-pixel using the luminance of the map image. This lets you create depth-of-field or selective focus effects where different regions have different blur amounts.

All processing is done in premultiplied alpha space to avoid dark halos at transparency boundaries.

Usage Examples

Basic: Soften an image

1. Add a Blur node between your source and Output
2. Set blur to (5, 5) for a gentle softening
3. Use quality: High for final renders, Draft for faster interaction

Creative: Directional motion blur

Set blur to (30, 0) for a horizontal motion-blur look, or (0, 30) for vertical. Animate the values for a directional wipe effect.

Advanced: Selective focus with blur map

1. Connect a Gradient node (radial mode) to the blur_map input
2. Set blur to (20, 20)
3. The gradient controls where the image is sharp vs. blurred, simulating depth of field

Tips

• The blur radius is linked (X and Y move together) by default. Click the link icon in Properties to unlink and set each axis independently.
• Clamp edge mode extends edge pixels outward (no dark borders). Transparent treats pixels outside the image as transparent (blurs to transparency at edges).
• Blur contributes to overscan computation, so content won't be clipped at comp boundaries even with very large radii.
• During playback, Draft quality is noticeably faster for large radii. Switch to High for final output.

Related Nodes

• Transform2D -- spatial positioning (blur should come after transform in the chain)
• Mix -- use a blurred version as the B input with a mask for selective blur
• Matte -- feather param applies a blur to the matte mask