User Manual

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NOTE: Since a perfect Gaussian filter would require examining an infinite number of
pixels, all practical Gaussians are, of necessity, approximations. The algorithm Fusion
uses is a highly-optimized approach that has many strengths, but can create visible
ringing around the edges in certain extreme cases. This ringing appears only when
blurring float-depth images and is normally far below the limits of visibility, especially in
final renders or HiQ mode, but may appear in subsequent processing. If you
experience this, selecting the Multi-box filter may be a good choice.
Controls Tab
The Controls tab contains the primary controls necessary for customizing the blur operation,
including five filter algorithms.
Filter
The Filter menu is where you select the type of filter used to create the blur.
Box Blur: This option is faster than the Gaussian blur but produces a
lower-quality result.
Bartlett: This option is a more subtle, anti-aliased blur filter.
Multi-box: Multi-box uses a Box filter layered in multiple passes to approximate a
Gaussian shape. With a moderate number of passes (e.g., four), a high-quality blur can
be obtained, often faster than the Gaussian filter and without any ringing.
Gaussian: Gaussian applies a smooth, symmetrical blur filter, using a sophisticated
constant-time Gaussian approximation algorithm.
Fast Gaussian: Gaussian applies a smooth, symmetrical blur filter, using a sophisticated
constant-time Gaussian approximation algorithm. This mode is the default filter method.
Color Channels (RGBA)
The filter defaults to operating on R, G, B, and A channels. Selective channel filtering is possible
by clicking each channel button to make them active or inactive.
NOTE: This is not the same as the RGBA checkboxes found under the common
controls. The node takes these selections into account before it processes the image,
so deselecting a channel causes the node to skip that channel when processing,
speeding up the rendering of the effect. In contrast, the channel controls under the
Common Controls tab are applied after the node has processed.
Lock X/Y
Locks the X and Y Blur sliders together for symmetrical blurring. This is enabled by default.
Blur Size
Sets the amount of blur applied to the image. When the Lock X and Y control is deselected,
independent control over each axis is provided.
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