stroblme
9f86845c25
- n3xd_ocp.sample.face_grid: a face's UV grid of points and outward normals in one GIL-free call, sampling exactly where np.linspace does so a caller's fitted surface does not move. - n3xd_ocp.helix: OCCT 8.0's TKHelix, which upstream does not bind at all. Takes Python lists rather than NCollection_Array1. Two things the header does not say, both found by probing: SetParameters wants N+1 diameters for N segments (one per boundary, so a taper interpolates), and the builder is right-hand only -- a negative pitch is error status 12, not a mirrored helix. - Bind BRepPrimAPI_MakeSphere and give inventory.py an EXTRA_SYMBOLS addendum for symbols no app source imports. assay's gen_flow_fixtures has been unrunnable since the 10C cutover for want of it; the gap was wider than --check, since sigdiff is inventory-driven too. Gates: 105 tests, 139/139 symbols, sigdiff clean, ASAN clean, wheel self-contained with no libGL/libX11 DT_NEEDED. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01HbTQ2HYWQwdtGmGJwypt6Z
n3xd-ocp
Hand-written nanobind wrapper for the OpenCASCADE (OCCT) geometry kernel.
In comparison to [cadquery-ocp](https://github.com/cadquery/OCP), we get superlinear 7.0x speedup on the use cases in n3xd`.
Start with docs/design.md for the decisions, docs/building.md to build one, and docs/adding-symbols.md to extend the surface.
Installation
As packages sit on our Gitea instance for, you must install by providing the specific url, like:
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.
Usage
OCP mirrors cadquery-ocp symbol-for-symbol, so code written against it runs unchanged:
from OCP.BRepPrimAPI import BRepPrimAPI_MakeBox
from OCP.BRepAlgoAPI import BRepAlgoAPI_Cut
from OCP.TopTools import TopTools_ListOfShape
box = BRepPrimAPI_MakeBox(10.0, 20.0, 30.0).Shape()
hole = BRepPrimAPI_MakeBox(3.0, 3.0, 30.0).Shape()
args, tools = TopTools_ListOfShape(), TopTools_ListOfShape()
args.Append(box)
tools.Append(hole)
cut = BRepAlgoAPI_Cut()
cut.SetArguments(args)
cut.SetTools(tools)
cut.Build()
result = cut.Shape()
One deliberate gap from upstream: constructors that run the algorithm immediately (the two-argument BRepAlgoAPI_Cut(a, b) form) aren't bound, only the deferred SetArguments/SetTools/Build() sequence above. See docs/design.md for why.
n3xd_ocp adds a handful of batch operations OCP doesn't have. They run on the same OCCT build and take/return plain OCP shapes:
import n3xd_ocp
areas, centroids = n3xd_ocp.measure.face_surface_props(result) # one call for every face
meshes = n3xd_ocp.tess.extract_meshes(result) # triangulated faces, ready to render
data = n3xd_ocp.bintools.write_bytes(result) # BREP bytes, no temp file needed
points, normals, uv_bounds = n3xd_ocp.sample.face_grid(face, 33) # a 33x33 UV grid on one face
n3xd_ocp.helix reaches OCCT 8.0's TKHelix, which upstream has no binding for. For N segments it wants N pitches, N turn counts and N+1 diameters — one per segment boundary, so consecutive values that differ taper across that segment:
from OCP.gp import gp_Ax3, gp_Dir, gp_Pnt
axis = gp_Ax3(gp_Pnt(0, 0, 0), gp_Dir(0, 0, 1), gp_Dir(1, 0, 0))
wire, tolerance_reached = n3xd_ocp.helix.pure_helix(axis, 8.0, [1.25], [12.0])
builder = n3xd_ocp.helix.BuilderHelix() # tapered, e.g. an NPT thread
builder.set_parameters(axis, [10.0, 8.0], [2.0], [4.0])
builder.set_approx_parameters(1.0e-4)
builder.perform()
Build
Wheels are built on a dev box and published to the Gitea package registry here.
If you want to make modifications or build it yourself, here are some shortcuts:
make image # compiles OCCT 8.0.1 into the builder image
make dev # incremental compile + tests
make wheel # compile, stubs, auditwheel, self-containment smoke test
make publish # publish to Gitea using .secret credentials