vertex_normals — 3D mesh_process op

• Data kinds: mesh → normals

• Call: import fullseye as fs; fs.ledger.vertex_normals(mesh) -> 'np.ndarray' (to call the implementation directly, import mesh_props; mesh_props.vertex_normals(mesh) -> 'np.ndarray'; from the registry, ops3d.get("vertex_normals"))

Usage

The vertex normals of a triangle mesh (unit normals aggregated with area weights). → (N,3).

The cross-product vector of each triangle (= face normal × 2·area) is scatter-added to its 3 vertices, then normalised per vertex. This gives an area-weighted average where larger (more important) faces contribute more, and the orientation is consistent with the face winding. Unlike normals_orient.estimate_normals (point cloud PCA, sign undetermined), no extra orientation step is needed.

Args:

mesh: tuple of (vertices (N,3), faces (M,3)).

Returns:

(N,3) unit vertex normals.

Raises:

ValueError: invalid shape, index out of range, or when there is a vertex whose normal cannot be defined (no incident face /

contributions cancel to zero).

Background guides (the physics and conventions behind this op)

• blender_interop — Using Blender alongside — build the shape, measure it with fullseye (pitfalls: axes, units, ground truth)

References (sample data, literature)

• 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.

Runnable examples (verified samples that actually call this op)

• mesh_props — py -3.11 examples_3d/mesh_props.py

Ops the type connects to (they accept normals as input)

icp_point2plane · compute_fpfh · shot_descriptor · fuse_to_voxel · reflect · refract · normal_consistency · ransac_cylinder

Same category (mesh_process)

laplacian_smooth · taubin_smooth · decimate_qem · face_normals · mesh_area · vertex_curvature · face_areas · mesh_volume


*Provenance: mesh_props.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.