Profile solids

profile_solid(sketch, features) turns a closed fit_curves sketch into a CAD solid through a CAD provider (roadmap 7.7.4): the sketch extruded along its plane's normal or revolved about an axis, then filleted, chamfered or shelled, written as STEP and tessellated. A turned or prismatic part becomes a clean solid from a few sections, and deviation compares it to the scan.

import meshioplusplus

section = meshioplusplus.slice(scan, origin, normal, chain=True)  # through the shaft's axis
sketch = meshioplusplus.fit_curves(section)
shaft, report = meshioplusplus.profile_solid(
    sketch, "revolve:0,0,0:0,0,1", "shaft.step", return_report=True
)
plate = meshioplusplus.profile_solid(outline, "extrude:0;fillet:0.5", scan=scan)  # to the scan's extent
meshioplusplus.deviation(scan, shaft)

Design

The roadmap asked for a design pass before code: the smallest scripted API, and where it stops.

• What it takes. One sketch (a line mesh with fit_curves' sketch:* field data, from a section, a silhouette or a DXF file) and a list of features applied in order. The first makes the solid, extrude or revolve; the rest modify it: fillet and chamfer (every edge) and shell (hollow to a wall, removing the face the extrusion ended at). That covers the turned shaft, the prismatic plate and the cast cup the roadmap names, and nothing else.
• Where it stops. No sketch constraints, no feature history with rebuilds and rollback, no edge selection beyond "every edge", no patterns or threads: the interactive parametric modeller is a non-goal (roadmap). A part needing more goes to a CAD tool as STEP, which is what profile_solid writes.
• Who builds it. The core chains the sketch's pieces into closed loops in world coordinates (the outer loop the one of largest area, wound counter-clockwise about the sketch's normal, the holes clockwise), resolves an extrusion of 0 to the scan's extent along the normal, and hands that to a named profile-solid provider (add_profile_solid_provider, the add_tet_mesher pattern; CadKernelProvider is untouched). OpenCASCADE's provider, "occt", builds the face, BRepPrimAPI_MakePrism or BRepPrimAPI_MakeRevol, BRepFilletAPI_MakeFillet, BRepFilletAPI_MakeChamfer and BRepOffsetAPI_MakeThickSolid, checks the solid, writes STEP (AP214, millimetres, a header free of time stamps, as fit_cad writes) and tessellates it. The pinned OpenCASCADE gains the TKFillet and TKOffset toolkits for it. Without a provider the call throws Unsupported (NotImplementedError in Python) naming OpenCASCADE.
• The features as text. The CLIs, the pipeline and the language bindings take the features as one text, ;-separated: extrude:D (extrude:D:symmetric half each way), revolve:OX,OY,OZ:DX,DY,DZ[:ANGLE] (360 by default), fillet:R, chamfer:D, shell:W. Python and C++ also take a list ({"kind": "extrude", "distance": 10}, ProfileFeature).

The report

volume, area, num_faces, valid (OpenCASCADE's check of the solid), provider and warnings. A 2 × 1 rectangle extruded by 3 is a valid six-faced box of volume 6; filleted by 0.1 it loses volume and gains faces; shelled by 0.1 it is a cup of volume 6 - 1.8 · 0.8 · 2.9; the half-section of a stepped shaft (radius 1 for 2, radius 0.6 for 1) revolved about its axis has volume 2.36 π, and a scan of the shaft lies within 0.05 of it on more than 95% of its points (tests/cpp/test_profile_solid.cpp).

Surfaces

C++ profile_solid, profile_features_from_text, profile_feature_from_name and the provider registry (operations/profile_solid.hpp); Python meshioplusplus.profile_solid, profile_features_from_text and profile_solid_providers (C++ core only); both CLIs (profile-solid SKETCH OUT --features TEXT [--step PATH] [--scan SCAN] [--provider NAME] [--deflection F] [--json]); the ProfileSolid pipeline step (Features, Step, Scan, Provider, Deflection); C mio_profile_solid (mio_profile_feature, 96 bytes, mio_profile_feature_init, mio_profile_features_from_text; mio_profile_solid_report, 64; mio_profile_solid_warnings, mio_has_profile_solid_provider); Fortran, Julia, R, Octave/MATLAB (features as text), WASM profileSolid (the full artifact, which carries OpenCASCADE); the MCP tool profile_solid.