volseq_pathline_render — LIVE4D flow op

• Data kinds: volseq → rgb

• Call: import fullseye as fs; fs.ledger.volseq_pathline_render(volseq, n_seeds: 'int' = 200, yaw: 'float' = 35.0, pitch: 'float' = 25.0, size: 'int' = 256, static_alpha: 'float' = 0.03, win: 'int' = 3, pyr_levels: 'int' = 3, iters: 'int' = 5, reg: 'float' = 0.001, seed: 'int' = 0, trail_sigma: 'float' = 0.7, min_speed: 'float' = 0.1, min_intensity: 'float' = 0.3) -> 'np.ndarray' (to call the implementation directly, import live4d; live4d.volseq_pathline_render(volseq, n_seeds: 'int' = 200, yaw: 'float' = 35.0, pitch: 'float' = 25.0, size: 'int' = 256, static_alpha: 'float' = 0.03, win: 'int' = 3, pyr_levels: 'int' = 3, iters: 'int' = 5, reg: 'float' = 0.001, seed: 'int' = 0, trail_sigma: 'float' = 0.7, min_speed: 'float' = 0.1, min_intensity: 'float' = 0.3) -> 'np.ndarray'; from the registry, opslive4d.get("volseq_pathline_render"))

Usage

A 3-D body of trajectories drawn by letting particles ride the flow (size, size, 3) (rgb) — shows the motion in a single still image.

Using the displacement field between adjacent frames (vol_flow_3d), n_seeds particles scattered from places that are moving (speed >= min_speed) and bright (at least min_intensity of the value range of the first frame = with structure) are advected following the mapping of the displacement field; the trajectories are drawn into a cube in the colour of time (blue = start → red = end) and composited from any viewpoint with vol_render_transfer. With static_alpha > 0 the brightness of the first frame is overlaid in faint grey (a cue to where things flowed). trail_sigma is the trajectory thickness (voxel). Flow in places without texture is undetermined (aperture problem), so seeds are limited to bright places -- choosing by speed alone drops seeds even into pitch-dark corners and the cube fills up with trajectories (measured).

Detailed usage guide

• live4d family guide

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• poc_live4d — py -3.11 examples/poc_live4d.py

Ops the type connects to (they accept rgb as input)

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Same category (flow)

vol_flow_3d · volseq_speed · volseq_pathline_orbit


*Provenance: live4d.py — LIVE4D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.