LevelSet

Within a single channel determined by the channel control, LevelSet outputs the distance from a pixel in the Viewer to the nearest pixel in the input channel with the value set in the threshold control.

LevelSet can be used to make high-quality dilate or unpremultiply operations. When gradient out is set to rgba, LevelSet outputs the motion vectors of pixels in the Viewer using the red (x axis) and green (y axis) values.

Inputs and Controls

Connection Type	Connection Name	Function
Input	unnamed	The input sequence to dilate or unpremultiply.

Control (UI)	Knob (Scripting)	Default Value	Function
LevelSet Tab
channel	channel	rgba.alpha	The levelset is only calculated for this channel.
threshold	threshold	0.5	Sets the pixel value that the Viewer pixel distance is measured from.
level set out	N/A	enabled	Enables the associated channel to the right. Disabling this checkbox is the same as setting the channel to none.
level set out	output	rgba.alpha	Write distance from the threshold crossing to this channel.
gradient out	gradient	motion	Write gradient vectors to these channels. These vectors point toward the threshold crossing.
create matte	create_matte	disabled	Output a matte channel rather than a level set.
dilate	matt_limit	0	Output matte is the level set thresholded at this value. This is a good way to grow a matte. Negative values shrink the matte.
extrapolate channels	extrapolated	none	If the creatematte button is turned on and extrapolatechannels is set to something other than none, the colors at the edge of the original matte are extrapolated as the matte is expanded. Unless gradientextrapolate is enabled, this function simply copy uses the color of the closest edge pixel.
gradient extrapolate	gradient_extrapolate	disabled	Instead of copying the nearest pixel, colors are extrapolated as a gradient to produce a ramp.