User Manual

 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 adds a soft glow, blurred by the Gaussian algorithm. This is the
default method.
Color Channels (RGBA)
The filter defaults to operating on R, G, B, and A channels. Selective channel filtering is possible
by clicking the channel buttons 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.
Threshold
This control is used to limit the effect of the soft glow. The higher the threshold, the brighter the
pixel must be before it is affected by the glow.
Gain
The Gain control defines the brightness of the glow.
Lock X/Y
When Lock X/Y is checked, both the horizontal and vertical glow amounts are locked.
Otherwise, separate amounts of glow may be applied to each axis of the image.
Glow Size
This amount determines the size of the glow effect. Larger values expand the size of the
glowing highlights of the image.
Num Passes
Available only in Multi-box mode. Larger values lead to a smoother distribution of the effect, but
also increase render times. It’s good to find the line between desired quality and acceptable
render times.
Clipping Mode
This option determines how edges are handled when performing domain-of-definition
rendering. This is profoundly important for nodes like Blur, which may require samples from
portions of the image outside the current domain.
 Frame: The default option is Frame, which automatically sets the node’s domain of
definition to use the full frame of the image, effectively ignoring the current domain
of definition. If the upstream DoD is smaller than the frame, the remaining area in the
frame is treated as black/transparent.
 Domain: Setting this option to Domain respects the upstream domain of definition
when applying the node’s effect. This can have adverse clipping effects in situations
where the node employs a large filter.
 None: Setting this option to None does not perform any source image clipping at all.
This means that any data required to process the node’s effect that would normally be
outside the upstream DoD is treated as black/transparent.
Chapter – 84 Blur Nodes 1836