normals_orient op• Data kinds: points × normals → normals
• Call: import fullseye as fs; fs.ledger.orient_normals(points, normals, k: 'int' = 20, seed_dir=None) -> 'np.ndarray' (to call the implementation directly, import normals_orient; normals_orient.orient_normals(points, normals, k: 'int' = 20, seed_dir=None) -> 'np.ndarray'; from the registry, ops3d.get("orient_normals"))
Orient the normals globally consistently by Hoppe's method (MST propagation). → (N,3).
Builds a minimum spanning tree on the kNN graph with weights 1 - |n_i·n_j| (cheaper the more aligned the tangent planes are), and makes each component internally consistent by BFS through the tree from a seed, flipping children whose sign is opposite to their parent. The seed is the point protruding furthest in the seed_dir direction when it is given, otherwise the outermost point (furthest from the centroid). If the graph is disconnected, a seed is taken and propagated independently per connected component (relative orientation between components is not guaranteed).
When seed_dir is passed, after propagation makes the component internally consistent, the projections of all points in the component are aggregated to align the global sign with seed_dir (it does not depend on the |cos| of a single seed, so even if the seed point's normal is nearly orthogonal to seed_dir the sign is reliably determined — finding [5]). A true degeneracy where seed_dir is (nearly) orthogonal to all normals of a component and the sign cannot be decided is fail-closed (ValueError). On closed surfaces (a sphere etc.) where seed_dir is orthogonal to the normals on average, the global sign is not unique, so the orientation based on the most protruding point (= outward) is kept. Without seed_dir, outward from the centroid.
Args:
points: (N,3) point cloud.
normals: (N,3) unoriented normals (normalised to unit length internally).
k: number of neighbours of the kNN graph.
seed_dir: global reference orientation (3,). If None, outward from the centroid is used as the reference.
Returns:
(N,3) unit normals with globally consistent sign.
Raises:
ValueError: when seed_dir is zero, or (in some connected component) is orthogonal to all normals so that
the global sign cannot be controlled (fail-closed).
• blender_interop — Using Blender alongside — build the shape, measure it with fullseye (pitfalls: axes, units, ground truth)
• 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.
• oriented_normals — py -3.11 examples_3d/oriented_normals.py
normals as input)icp_point2plane · compute_fpfh · shot_descriptor · fuse_to_voxel · reflect · refract · normal_consistency · ransac_cylinder
normals_orient)*Provenance: normals_orient.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.