terrain op• Data kinds: mesh → matrix
• Call: import fullseye as fs; fs.ledger.displacement_band_weights(V, F, wavelengths=(0.06, 0.03, 0.015, 0.0075, 0.00375), *, nyquist: 'float' = 2.0, fade: 'float' = 1.0, local_edge=None) -> 'np.ndarray' (to call the implementation directly, import render3d; render3d.displacement_band_weights(V, F, wavelengths=(0.06, 0.03, 0.015, 0.0075, 0.00375), *, nyquist: 'float' = 2.0, fade: 'float' = 1.0, local_edge=None) -> 'np.ndarray'; from the registry, ops3d.get("displacement_band_weights"))
Per-octave, per-vertex band gate (K, N) in [0,1].
It is 1 where the mesh can carry the wavelength as geometry, 0 where it would alias.
A vertex with local edge length e (mean incident edge, mesh_edge_lengths, or local_edge (N,) if given) carries wavelength λ only when λ ≥ nyquist·e; the gate rises linearly from 0 at λ = nyquist·e to 1 at λ = (nyquist+fade)·e (fade=0 → hard cut). Used two ways by the Itokawa pipeline: (i) on the *rendered* mesh to decide which octaves may be displaced (the rest go to bump normals); (ii) on the *source* model to measure which wavelengths the real data already carries — the complement 1 − gate is the synthetic-relief weight (0 where the data are fine, 1 where they are coarse), so dense regions are not double-textured. Deterministic.
For ratio = λ_k / e_i the computation is the binary gate = (ratio ≥ nyquist) when fade == 0, otherwise gate = clip((ratio − nyquist) / fade, 0, 1). Returns float64 (K, N) (K = number of wavelengths, N = number of vertices).
• wavelengths: sequence of wavelengths in mesh units (empty, non-positive or non-finite raises ValueError). Pass the same sequence as to mesh_displace_spectrum.
• nyquist: lower bound of the wavelength/edge-length ratio regarded as "carriable as geometry" (default 2 = 2 edges per 1 wavelength). 0 or less raises ValueError.
• fade: transition width (in multiples of the edge length). 0 gives a hard threshold. Negative raises ValueError.
• local_edge: when you supply the per-vertex edge length (N,) yourself (equivalent to per='vertex' of mesh_edge_lengths). A length mismatch, non-positive or non-finite values raise ValueError. If None, mesh_edge_lengths is called internally.
mesh_displace_spectrum calls this function internally, so you normally do not need to call it directly. You use it directly when measuring the wavelengths the source data already carries and passing 1 − gate as weights (so as not to put synthetic relief twice on the fine parts), and when deciding the remainder to route to bump_normals_fbm.
• 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.
• itokawa_regolith_hero — py -3.11 examples_3d/itokawa_regolith_hero.py
matrix as input)terrain)mesh_displace_fbm · terrain_region_mask · mesh_scatter_boulders · mesh_edge_lengths · mesh_subdivide · mesh_displace_spectrum · bump_normals_fbm
*Provenance: render3d.py — 3D 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.