67 lines
2.5 KiB
Markdown
67 lines
2.5 KiB
Markdown
# n3xd-ocp
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Hand-written [nanobind](https://github.com/wjakob/nanobind) wrapper for the OpenCASCADE (OCCT) geometry kernel.
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In comparison to [`cadquery-ocp](https://github.com/cadquery/OCP), we get superlinear 7.0x speedup on the use cases in `n3xd`.
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Start with [docs/design.md](docs/design.md) for the decisions,
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[docs/building.md](docs/building.md) to build one, and
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[docs/adding-symbols.md](docs/adding-symbols.md) to extend the surface.
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## Installation
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As packages sit on our Gitea instance for, you must install by providing the specific url, like:
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```bash
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uv pip install --index-url https://git.stroblme.de/api/packages/N3XD/pypi/simple/ \
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--prerelease=allow n3xd-ocp
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```
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Versions are `<occt-version>.N`, enforced at configure time against the OCCT actually found.
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## Usage
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`OCP` mirrors [`cadquery-ocp`](https://github.com/cadquery/OCP) symbol-for-symbol, so code written against it runs unchanged:
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```python
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from OCP.BRepPrimAPI import BRepPrimAPI_MakeBox
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from OCP.BRepAlgoAPI import BRepAlgoAPI_Cut
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from OCP.TopTools import TopTools_ListOfShape
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box = BRepPrimAPI_MakeBox(10.0, 20.0, 30.0).Shape()
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hole = BRepPrimAPI_MakeBox(3.0, 3.0, 30.0).Shape()
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args, tools = TopTools_ListOfShape(), TopTools_ListOfShape()
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args.Append(box)
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tools.Append(hole)
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cut = BRepAlgoAPI_Cut()
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cut.SetArguments(args)
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cut.SetTools(tools)
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cut.Build()
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result = cut.Shape()
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```
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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](docs/design.md) for why.
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`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:
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```python
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import n3xd_ocp
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areas, centroids = n3xd_ocp.measure.face_surface_props(result) # one call for every face
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meshes = n3xd_ocp.tess.extract_meshes(result) # triangulated faces, ready to render
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data = n3xd_ocp.bintools.write_bytes(result) # BREP bytes, no temp file needed
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```
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## Build
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Wheels are built on a dev box and published to the Gitea package registry [here](https://git.stroblme.de/api/packages/N3XD/pypi).
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If you want to make modifications or build it yourself, here are some shortcuts:
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```bash
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make image # compiles OCCT 8.0.1 into the builder image
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make dev # incremental compile + tests
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make wheel # compile, stubs, auditwheel, self-containment smoke test
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make publish # publish to Gitea using .secret credentials
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``` |