smallest_box3 — 3D geometry op

• Data kinds: points → primitive

• Call: import fullseye as fs; fs.ledger.smallest_box3(points) -> 'dict' (implementation को सीधे call करना हो तो import measure3d; measure3d.smallest_box3(points) -> 'dict', registry से लेना हो तो ops3d.get("smallest_box3"))

उपयोग

लगभग न्यूनतम volume वाला oriented bounding box (3-D smallest_rectangle2)।

> नीचे का विस्तृत विवरण मूल text में है — सारांश और headings का अनुवाद हो चुका है।

Found by multi-start local refinement: seed the orientation from every convex- hull face normal (the O'Rourke *case a* candidates — a box face flush with a hull face), from the PCA axes, and from a fixed set of deterministic random frames, then polish each by coordinate descent and keep the least-volume result. This is exact for box-like objects (a rotated cuboid is recovered to machine precision) and, unlike a PCA box (fit_box3 / pcseg.obb), reaches the true minimum on shapes whose optimum has no face flush with a hull face — e.g. a regular tetrahedron, where the PCA / hull-face box is ~2x too large.

Honest limit: this is not a *proof* of global minimality for every convex shape. The exact guarantee needs O'Rourke's full *case b* (two box faces each flush with a hull edge), which is not enumerated here; local refinement drives seeds into that regime instead. Empirically the result is at or below a dense brute-force rotation search, but a pathological shape could leave a small gap.

Returns center (cd/cr/cc), axes (3, 3 — unit ROW vectors), sorted half-extents l1 >= l2 >= l3, full size, volume, and corners (8, 3). Deterministic (fixed random seeds). Raises ValueError on < 4 points or a coplanar/degenerate set (no 3-D hull).

संदर्भ (sample data, साहित्य)

• Sample data catalog (DL URL / license) — 2-D के लिए skimage.data (BSD/public) + synthetic, 3-D के लिए real data sources (Stanford/PDS आदि) के DL URL।

• Operators का स्रोत और संदर्भ — इस op family के मूल research/methods के स्रोत।

चलाए जा सकने वाले उदाहरण (verified samples जो सच में यह op call करते हैं)

• oriented_bounding_box — py -3.11 examples_3d/oriented_bounding_box.py

वे अगले ops जिनसे type जुड़ता है (primitive को input के रूप में लेते हैं)

fuse_to_voxel · angle_between_lines · angle_between_planes · angle_line_plane · distance_point_plane · distance_point_line · distance_line_line · distance_segment_segment

इसी category के (geometry)

line_from_2points · plane_from_3points · angle_3points · angle_between_lines · angle_between_planes · angle_line_plane · distance_point_plane · distance_point_line


*Provenance: measure3d.py — 3D operator registry. यह per-op note tools/opdocs.py md से अपने-आप generate होता है (हाथ से edit न करें)।*

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