138/138 symbols across 53 modules. New: IFSelect, Interface, XSControl, IGESData, STEPControl, IGESControl, RWStl, Graphic3d, NCollection, StdPrs. **The full app suite passes against this wheel: 1797 passed, 1 skipped — the same result as the stock wheel**, run from the parity venv. Getting there needed six methods that no static analysis could have found: `inventory --check` only sees symbols reached through an import, so a method called on an instance is invisible to it. The suite found them in one pass, and one of them (gp_Vec.Reverse, which every outward-normal probe calls) accounted for 311 of the 255 failing tests on its own. The others: gp_Trsf.SetMirror over a plane and a point, Geom_Surface.D0, BRep_Builder.MakeFace from a triangulation, MakePipeShell.SetMode with a fixed binormal, and MakeFace from a surface plus tolerance. Open question **S5 is settled: no**. The wheel does not need OCCT's share/ resources. test_inc3_io.py asserts no CSF_* variable is set and then round-trips STEP and IGES, reading the declared units back off both — which is exactly the resource-less container the question was about. The XSTEP readers keep the GIL, amending the blanket "file readers and writers" line in design.md's GIL policy. STEP and IGES traffic in process-global Interface_Static state, the IGES reader is documented as not thread-safe, and the app already serialises imports behind a lock — so holding it costs nothing and removes a class of question. RWStl, which touches no global state, releases. XSControl_Reader and IGESData are registered although the app imports neither: they are the reader base both concrete readers inherit their transfer surface from, and the model-to-global-section chain the IGES unit probe walks. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01DfriM8XUkn7uYf5Dwe2xo6
n3xd-ocp
Hand-written nanobind bindings for the
OpenCASCADE (OCCT) geometry kernel, covering exactly the surface the N3XD CAD
backend uses — 139 symbols across 48 OCP.* modules, not all of OCCT.
The package installs as a top-level OCP, so it is a drop-in replacement for
cadquery-ocp-novtk and the app's 442 import sites stay untouched.
Status: Inc 0 (spike) shipped — build system, OCCT builder image, handle
model, and the first module surface (gp, TopAbs, TopoDS, TopExp,
TopLoc, TopTools, BRep, BinTools, Poly, Standard), published as
7.9.3.1.dev1. BREP serialisation is byte-identical to the stock wheel, which
is the gate that mattered: the pools and the content-addressed derive payloads
both depend on it. Coverage is 34 of the 139 symbols the app imports; the rest
lands in increments 1-4 (roadmap 10C).
Start with docs/design.md for the decisions,
docs/building.md to build one, and
docs/adding-symbols.md to extend the surface. The
phase plan lives in the app repo at docs-private/reference/roadmap.md
(Phase 10).
Why
cadquery-ocp lags OCCT (it wraps 7.9.3; OCCT 8.0 shipped 2026-05), builds
Windows and macOS wheels we never use, and until recently forced a 638 MB VTK
dependency into the image. Binding call overhead is not a bottleneck — the
CAD hotspots live inside the C++ kernel — so this exists for version velocity,
footprint, and two defects that a binding we control prevents by construction:
- OCCT sub-shapes are returned by value, so a wrapper can never alias a
TShapewhose owner has died (this segfaulted a process-global face memo). - Executing constructors (the two-argument
BRepAlgoAPI_*forms) are not bound, so the double-execution footgun is unrepresentable.
It also releases the GIL around kernel calls and ships type stubs, neither of which upstream does.
Build
OCCT is compiled once into a builder image and reused; it is never built on the production host (4 cores, and a kernel build is multi-hour). Wheels are built here on a dev box and published to the Gitea package registry.
make image # once, ~40 min: compiles OCCT 7.9.3 into the builder image
make dev # inner loop: incremental compile + tests
make wheel # compile, stubs, auditwheel, self-containment smoke test
make publish # -> https://git.stroblme.de/api/packages/N3XD/pypi
Credentials go in .secrets (gitignored) as UV_PUBLISH_USERNAME /
UV_PUBLISH_PASSWORD. Consumers read anonymously — the package is public:
uv pip install --index-url https://git.stroblme.de/api/packages/N3XD/pypi/simple/ \
--prerelease=allow n3xd-ocp
Versions are <occt-version>.N, enforced at configure time against the OCCT
actually found, so the kernel a wheel wraps is readable from its version alone.
The registry refuses to republish a version; iteration builds therefore carry a
.devN suffix and are the only ones the registry's cleanup rule collects.