curve3d_tube_mesh — 3D surface op

• Data kinds: points → mesh

• Call: import fullseye as fs; fs.ledger.curve3d_tube_mesh(points, radius=0.1, segments=12, closed=False) (to call the implementation directly, import render3d; render3d.curve3d_tube_mesh(points, radius=0.1, segments=12, closed=False); from the registry, ops3d.get("curve3d_tube_mesh"))

Usage

A space curve as a tube mesh — the MATLAB `tubeplot`, with a volume you can check.

Sweeps a circle of *radius* along the polyline using a parallel-transport

frame (no Frenet frame: the normal of a straight segment is undefined and the

binormal flips at an inflection, which twists the tube). Returns

`(vertices, faces)` for the existing 3-D viewers and mesh ops.

★Why this earns its place: for a closed circular centre line the tube is a

torus, whose volume `2 pi^2 R r^2 and area 4 pi^2 R r` are analytic —

and the existing `mesh_volume / mesh_area` ops measure the result. Two

independent implementations meeting at a closed form is a real check; "it

looks like a tube" is not.

Raises `ValueError`: fewer than 2 points; not (N, 3); radius not

positive; fewer than 3 segments; non-finite input; a curve with repeated

consecutive points (the direction is undefined there).

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)

• minimal_surfaces — py -3.11 examples_3d/minimal_surfaces.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 (surface)

minimal_surface · minimal_surface_bend · gyroid_isosurface · gyroid_solid_mask


*Provenance: render3d.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.