terrain op• Data kinds: normalmap × pointmap → normalmap
• Call: import fullseye as fs; fs.ledger.bump_normals_fbm(normals, positions, wavelengths=(0.002, 0.001), amplitudes=(0.0002, 0.00012), *, seed: 'int' = 0, rotation=None, step=None, local_edge=None, nyquist: 'float' = 2.0, fade: 'float' = 1.0) -> 'np.ndarray' (to call the implementation directly, import render3d; render3d.bump_normals_fbm(normals, positions, wavelengths=(0.002, 0.001), amplitudes=(0.0002, 0.00012), *, seed: 'int' = 0, rotation=None, step=None, local_edge=None, nyquist: 'float' = 2.0, fade: 'float' = 1.0) -> 'np.ndarray'; from the registry, ops3d.get("bump_normals_fbm"))
Perturb a normal map with the *gradient* of a seeded multi-octave height field
> The detailed description below is the original text — the summary and the headings are translated.
(sub-facet relief the geometry cannot afford to displace) → unit normals `(H, W, 3)`.
`h(x) = Σ_k A_k n_k(x) is the same value-noise field :func:mesh_displace_spectrum`
would displace with (same `seed` ⇒ same lattice), so passing the octaves that the
displacement's band gate rejected makes the shading continue the *same* amplitude
spectrum below the facet size (no fake sandpaper: an octave of amplitude `A` at
wavelength `λ tilts the normal by about 2πA/λ` at most). The bumped normal is
`normalize(n − ∇_t h)` (first-order shading normal of a height field over the
surface; `∇_t = tangential gradient by central differences with step` =
`min(λ)/64). positions are world coordinates (H, W, 3)` (NaN = background,
left untouched); if `rotation (3×3, world → normal frame, e.g. pose[:3,:3]`)
is given the normals are taken in that frame.
`local_edge (optional (H, W)` map of the mesh's local edge length under each
pixel) makes the bump the exact complement of the displacement's band gate: octave
`k is bumped with weight 1 − gate_k where gate_k` is
:func:displacement_band_weights's rule with the same `nyquist / fade` — so an
octave the geometry carried at a pixel is not added twice, and one it could not carry
is fully supplied by the bump. Without it every octave is bumped at full amplitude.
Deterministic; fail-closed.
入出力はともに `(H, W, 3) 画像。positions` に NaN を含む画素、または法線の長さが
`1e-12 以下の画素は背景として **元の値のまま** 残す(render3d.render_mesh` の空画素)。
有効画素が一つも無ければ入力のコピーを返す。
• `wavelengths / amplitudes: メッシュ(= positions`)の単位で同じ長さ(1〜32)の
正の列。不一致・負は `ValueError`。
• `rotation: 3×3(world → 法線の座標系)。与えると法線を N @ R` で world に戻して
勾配を取り、`@ R.T で元の系に戻す。render_mesh` の法線はカメラ空間なので
`pose[:3,:3] を渡す。非有限・形不正は ValueError`。
• `step: 中心差分の刻み(既定 min(wavelengths)/64)。0 以下は ValueError`。
• `local_edge: (H, W)` の辺長マップ。形が法線と違う、または有効画素の下に非正・
非有限があると `ValueError`。
高さ場を 3 軸の中心差分で微分するので評価は 1 画素あたり 6 回。法線の傾きは
`max |∇h| ≈ 2π A_k / λ_k` 程度なので、振幅が波長に近づくほど法線が大きく寝る
(既定は A/λ = 0.1 前後)。結果は `phong_shade / brdf_hapke` 等の
法線マップ入力へそのまま渡せる。
• 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
normalmap as input)fuse_to_voxel · render_shaded · phong_shade · matcap_shade · brdf_lommel_seeliger · brdf_hapke · integrate_normals · render_lambertian
terrain)mesh_displace_fbm · terrain_region_mask · mesh_scatter_boulders · mesh_edge_lengths · mesh_subdivide · displacement_band_weights · mesh_displace_spectrum
*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.