terrain op• データ種: mesh → mesh
• 呼び出し: import fullseye as fs; fs.ledger.mesh_scatter_boulders(V, F, *, density: 'float', d_min: 'float', d_max=None, exponent: 'float' = 3.1, seed: 'int' = 0, region_weights=None, aspect=(1.0, 0.7, 0.5), embed: 'float' = 0.35, subdiv: 'int' = 1, shape: 'str' = 'ellipsoid', orientation: 'str' = 'normal', burial=(0.3, 0.6), max_count=None, hull_points=None, return_info: 'bool' = False) (実装を直接呼ぶなら import render3d; render3d.mesh_scatter_boulders(V, F, *, density: 'float', d_min: 'float', d_max=None, exponent: 'float' = 3.1, seed: 'int' = 0, region_weights=None, aspect=(1.0, 0.7, 0.5), embed: 'float' = 0.35, subdiv: 'int' = 1, shape: 'str' = 'ellipsoid', orientation: 'str' = 'normal', burial=(0.3, 0.6), max_count=None, hull_points=None, return_info: 'bool' = False)、台帳から引くなら ops3d.get("mesh_scatter_boulders"))
半ば埋まった岩塊をメッシュ上に散布する(サイズはべき則、seed 付き)→ (V, F)。
(or (V, F, info) with return_info=True).
shape='ellipsoid' (default, unchanged behaviour): icosphere ellipsoids with semi-axes D/2 × aspect (1 : 0.7 : 0.5, shortest axis along the local surface normal), spun about the normal and sunk by embed (0 = resting, 1 = centre on the surface). shape='hull': angular blocks — the convex hull of seeded random points on an ellipsoid of the same aspect with 20 % radial jitter (flat facets, sharp edges, the look of Itokawa's boulders), hull_points per block (default size-dependent:
10 + 8·log2(D/d_min), 10..40). orientation='random' gives each block a uniform random rotation instead of aligning its short axis with the normal. For hulls the sink is the size-dependent burial fraction from sample_boulders (30–60 % of the block's height below the surface by default; embed is ignored). max_count caps the expected number by raising d_min along the same law (see sample_boulders; info['d_min_effective'] reports it).
Placement and sizes come from sample_boulders (Poisson process, N(>D) ∝ D^-exponent); boulders sit on the mesh *as passed* — pass the displaced / subdivided terrain so they rest on the final surface. region_weights from terrain_region_mask keeps the seas smooth. The boulders are appended as real geometry, so they self-shadow, cast shadows and occlude through the same rasteriser / ray-cast path as the terrain. info = the sample dict plus faces_per_boulder and n_boulders. Deterministic under seed. Fail-closed.
手順: sample_boulders で位置(面上の一様点)・面法線・直径 D を引き、岩ごとに小さなメッシュを作って入力メッシュの後ろに連結する(頂点は末尾に追加、面 index はオフセット済み)。入力の頂点・面はそのまま残るので、info['faces_per_boulder'] と元の面数から岩の面だけを切り出せる。
• density: 単位面積(メッシュ単位²)あたりの D ≥ d_min の岩の期待個数。実個数はポアソン分布で決まり 0 個もあり得る(そのときは入力のコピーを返す)。
• d_min < d_max(None = 10·d_min)、exponent > 0、aspect は正の 3 要素、embed ∈ [0, 1]、subdiv ∈ [0, 3] (楕円体の icosphere 細分)、hull_points は [6, 200]。いずれも範囲外は ValueError。
• shape='ellipsoid': 半軸 D/2·aspect の楕円体を最短軸が法線に沿う向きで置き、中心を法線方向に semi_z·(1 − embed) 浮かせる。
• shape='hull': 楕円体上の乱数点の凸包。法線方向の高さ範囲のうち burial (0.3〜0.6 既定、小さい岩ほど深い)の割合が面の下に沈む。embed は無視。
• orientation='random' は一様ランダム回転(4 元数)。'normal' は法線まわりにランダム回転。回転の乱数は seed + 1 の generator を使う。
岩は実ジオメトリなので ambient_occlusion / cast_shadow / shadow_raycast のレイに普通に当たる。置く面は渡したメッシュそのものなので、mesh_displace_spectrum や mesh_subdivide の 後 に呼ぶこと(先に呼ぶと岩が地面から浮く/埋まる)。
• サンプルデータ カタログ(DL URL / ライセンス) — 2-D は skimage.data(BSD/public)+ 合成、3-D は実データ源(Stanford/PDS 等)の DL URL。
• 演算子の来歴・参考文献 — この op 族の元になった研究/手法の出典。
• itokawa_regolith_hero — py -3.11 examples_3d/itokawa_regolith_hero.py
mesh を入力に取れる)mesh_to_voxel · mesh_to_points · to_points · fuse_to_voxel · ambient_occlusion · cast_shadow · supersample_mesh · render_beauty
terrain)mesh_displace_fbm · terrain_region_mask · mesh_edge_lengths · mesh_subdivide · displacement_band_weights · mesh_displace_spectrum · bump_normals_fbm
*Provenance: render3d.py — 3D operator registry. この per-op ノートは tools/opdocs.py md が自動生成(手編集しない)。*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.