forked from 1b-agent/fieldcraft-upstream
4667655e08
* mesh: exact predicates (Shewchuk adaptive orient/incircle/insphere), symbolic perturbation, indirect LPI/TPI predicates Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * mesh: predicate benchmark (filter hit rate, CAD-degenerate inputs); record the predicate decision Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * mesh: simplify predicates (destructuring over fallbacks, shared-minor exact insphere, cheaper expansion product) Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm --------- Co-authored-by: jyviko <[email protected]> Co-authored-by: Claude Opus 5.5 <[email protected]>
81 lines
4.8 KiB
Markdown
81 lines
4.8 KiB
Markdown
# ADR 0001: Libraries and licences
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Status: accepted (2026-10-13)
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## Context
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ModelCraft is MIT OR Apache-2.0. Everything it links must allow that, and the meshing and solver
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algorithms, where the obvious open-source implementations are GPL-family, must come from papers.
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## Decision
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**Geometry: SolidCraft**, as git dependencies pinned by rev (`solidcraft-kernel`,
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`solidcraft-geom`, `solidcraft-doc`, `solidcraft-io`; MIT OR Apache-2.0, built on the Apache-2.0
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truck crates). SolidCraft is the primary geometry source: ModelCraft opens SolidCraft designs and
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meshes from SolidCraft's tessellation, and reads face-tagged meshes SolidCraft exports. Other CAD
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exchange files (STEP, which SolidCraft's kernel already reads) can be added as secondary inputs
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through the same crate. Only `modelcraft-geometry` may depend on SolidCraft.
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**Meshing: our own**, implemented from published papers (`docs/meshing/literature.md`).
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Robust predicates follow Shewchuk's adaptive-precision arithmetic (the paper; his reference
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`predicates.c` is public domain). A permissive crate may be adopted instead after review; record
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it here. *Decided 2026-10-13:* our own implementation, `modelcraft_mesh::predicates`, written from
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Shewchuk 1997, Devillers–Teillaud 2011 and Attene 2020 (no `unsafe`, deterministic, wasm-safe, a
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validated coordinate domain instead of Shewchuk's overflow/underflow caveat, and indirect
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predicates that `robust` lacks). `robust` (georust, MIT OR Apache-2.0) and `num-bigint` /
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`num-rational` / `num-traits` (MIT OR Apache-2.0) are dev-dependencies only: differential test
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oracles, never linked into ModelCraft.
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**Linear algebra:** to be decided in the solver task, among permissively licensed pure-Rust
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crates (for example `faer`, MIT). Record the choice here.
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**Allowed:** MIT, BSD-2/3, Apache-2.0, ISC, Zlib, Unicode, MPL-2.0 (as an unmodified dependency),
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CC0 and public domain.
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**Rejected — never read, copy or link:**
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| Project | Licence | Would have offered |
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|---|---|---|
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| TetGen | AGPL-3.0 | constrained Delaunay tetrahedralization |
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| CGAL | GPL-3.0 / LGPL-3.0 | Delaunay, mesh generation |
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| Gmsh | GPL-2.0+ | tet and hex meshing |
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| Netgen | LGPL-2.1 | tet meshing |
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| CalculiX | GPL-2.0 | implicit solver, Abaqus-like input |
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| Code_Aster | GPL-3.0 | implicit solver |
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| OpenRadioss | AGPL-3.0 | explicit solver |
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| Elmer | GPL-2.0 / LGPL-2.1 | multiphysics solver |
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| deal.II, FreeFEM, Salome | LGPL | FE libraries, pre-processing |
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| OpenCASCADE | LGPL-2.1 | B-rep kernel |
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| Attene's CDT, Indirect_Predicates, VolumeMesher | GPL / LGPL | robust CDT, indirect predicates (implement from the papers) |
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| TetWild (original), Evocube, robustPolycube, ultimaille, invertible-maps | GPL-3.0 / AGPL-3.0 | tet meshing, polycube, injective maps |
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| libHexEx, libHexHex, QGP3D, MC3D, CoMISo, Graphite | GPL | integer-grid-map hex extraction, quantization |
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| Shewchuk's Triangle | non-commercial only | 2D meshing |
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| geogram `third_party/tetgen`, `third_party/triangle` and their wrappers | AGPL / non-commercial | (the rest of geogram is BSD-3 and readable) |
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| libigl `copyleft/` modules | GPL | (libigl core is MPL-2.0 and readable) |
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| OpenVolumeMesh, CGoGN | believed LGPL, unverified | treat as forbidden until checked |
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**Repositories without a licence are all rights reserved: never read them** (for example Gao
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2019's octree hex code, LoopyCuts). Readable references for the meshing work (re-implement from
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the paper, note anything adapted in ATTRIBUTION.md): Shewchuk's `predicates.c` (public domain),
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`georust/robust` (Apache-2.0), geogram (BSD-3, exclusions above), fTetWild (MPL-2.0), CinoLib,
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Gen-Adapt-Ref, HexaLab, robust_hex_dominant_meshing (MIT), quartet (ISC). The full table with
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sources is in `docs/meshing/literature.md`.
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**Test geometry** follows the same rule as test data: nothing produced with a commercial CAD or
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CAE product. That excludes ABC (Onshape), MAMBO (files from commercial translators) and the HexMe
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models that come from ABC, GrabCAD or Siemens NX; HexMe's Gmsh-made models are allowed (CC-BY-4.0).
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Thingi10K is not used either (owner decision 2026-10-13: authoring tools unrecorded). **The test
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corpus is our own:** parts built with SolidCraft (scripts or designs authored in SolidCraft,
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committed as their recipes so the geometry is regenerated, not stored) and analytic shapes.
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**Commercial products** (Abaqus, Nastran, LS-DYNA, LS-PrePost, HyperMesh, ANSA, Femap, Patran,
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ANSYS) are never run, scripted or used as a source of data. Deck formats come from the vendors'
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public reference manuals, described in our own words with our own examples.
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## Consequences
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- The tet and hex meshers are significant original work; the literature survey decides the
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order and the methods.
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- SolidCraft and ModelCraft move together: bumping the pinned rev bumps the repeated
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`[patch.crates-io]` entries in the same commit.
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