face_normals — 3D `mesh_process` op

• Data kinds: mesh → normals

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

Usage

The face normals of a triangle mesh (the unit normal of each triangle). → (M,3).

Normal = normalised cross(v1−v0, v2−v0). The orientation is determined consistently by the winding order of faces (there is no sign ambiguity as with PCA). If a closed mesh is built with outward winding, all normals point outward.

Args:

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

Returns:

(M,3) unit face normals.

Raises:

ValueError: invalid shape, index out of range, or when a degenerate (zero-area) triangle has no defined normal.

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 · vertex_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).*

face_normals — 3D mesh_process op