alpha_shape_mesh — 3D `reconstruct` op

• Data kinds: points → mesh

• Call: import fullseye as fs; fs.ledger.alpha_shape_mesh(points, alpha) (to call the implementation directly, import recon3d; recon3d.alpha_shape_mesh(points, alpha); from the registry, ops3d.get("alpha_shape_mesh"))

Usage

The triangulated surface mesh by alpha shapes (point set → (vertices, faces)).

Returns the same boundary triangles as alpha_shape_boundary as a mesh repacked to only the vertices used. A surface spanned directly from the point cloud without going through voxels. Preserving concavities / holes is what sets it apart from the marching-cubes family.

Parameters

points : array_like (N,3)

alpha : float

Positive real number (radius threshold 1/alpha).

Returns

vertices : numpy.ndarray (V,3) float64

Input points used on the boundary (repacked).

faces : numpy.ndarray (F,3) int64

Triangle indices referring to vertices. If there is no boundary, (0,3)/(0,3).

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)

• alpha_shape_topology — py -3.11 examples_3d/alpha_shape_topology.py

Ops the type connects to (they accept `mesh` as input)

mesh_to_voxel · mesh_to_points · to_points · fuse_to_voxel · ambient_occlusion · cast_shadow · supersample_mesh · render_beauty

Same category (`reconstruct`)

poisson_lite · alpha_shape_boundary · estimate_alpha

*Provenance: recon3d.py — 3D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

alpha_shape_mesh — 3D reconstruct op