Trace¶

Animate lines being drawn stroke by stroke. Trace Engine selects how image contours are followed, while Trace Mode controls drawing progress.

Trace engine¶

Parameter	Description
Trace Engine	Pixel Walk connects edge pixels into strokes (default). Vector Signal draws continuous contours as a scanning signal.
Contour Level	The luminance or alpha level followed by Vector Signal. Default: 50%. Start at 50% for black-and-white footage.
Signal Resolution	Maximum analysis dimension for Vector Signal (64-2048; default 2048). Higher values capture more detail; lower values reduce processing cost.

Start with Vector Signal when consistent drawing order matters for moving images or video. Pixel Walk is the default, so switch explicitly to use Vector Signal.

How the extracted lines differ¶

Scan Source	Pixel Walk	Vector Signal
Edges	Extracts luminance edges.	Follows luminance contours at Contour Level, using Threshold to reject weak contours.
Luminance	Draws bright regions.	Follows luminance contours at Contour Level. Threshold has no effect.
Alpha Outline	Extracts alpha edges.	Follows alpha contours at Contour Level, using Threshold to reject weak contours.
Mask Paths / Audio Waveform	Draws lines directly from masks or audio.	Unchanged by the Trace Engine selection.

The two engines extract different lines from photographic footage. If Vector Signal produces no lines, adjust Contour Level. Colors in transparent pixels are excluded from luminance contours.

Drawing progress¶

Parameter	Description
Trace Mode	Manual uses Completion; Auto Once draws once; Auto Loop repeats; Auto Ping-Pong moves back and forth.
Trace Completion	Completion in Manual mode. Keyframe 0-100% for a stroke-by-stroke reveal.
Trace Speed	Speed in automatic modes, in percent per second (up to 3000%). 25% completes a scan in 4 seconds; 3000% completes one in 1/30 second.
Trail Fade	Fades the beam after it is drawn. Higher values create a shorter-lived trailing line.

Vector Signal's Auto Loop also draws the portion traversed during the frame's time interval. This helps avoid missing lines when scan speed and frame rate synchronize.

Drawing order and hardware character¶

Pixel Walk draws the stroke nearest to the current endpoint next. Vector Signal aligns contour starting points, directions and spatial ordering, grouping inner closed contours with their outer contour.

Parameter	Description
Retrace Lines	Beam flyback lines between contours. 0% hides them.
Corner Glow	Bright points at corners and endpoints. Combine with Line Quantize to emphasize corners.
Beams	Number of beams sharing the trace (1-8).
Trace Start	In Pixel Walk, the position used to choose the first stroke. In Vector Signal, the relative starting point within each contour's bounds.
Trace Reverse	Reverses drawing direction and order.
Source Ray	Rays from a source point to each beam head.
Ray Origin	The origin of Source Ray.

Vector Signal handles thin lines, drawing boundaries and highlights at subpixel coordinates. Smoothing uses the contour's actual length to reduce changes in rounding as movement direction changes. Pixel Perfect uses integer-pixel rendering.

Base guide lines¶

Parameter	Description
Base Line Color	Color of sections that have not yet been traced.
Base Line Opacity	Guide-line opacity (0 hides the guide).

Display the original lines faintly so the beam appears to trace over them.