OneCAD-Simulation/ROADMAP.md

# Roadmap

ModelCraft's goal is CAE modeling on par with Abaqus/CAE, Nastran pre-processors and LS-PrePost,
with hexahedral meshing as the centre of gravity, plus its own linear solver. Abaqus/CAE is the
reference for scope (its documentation is excellent and its solver strong); its application is
where we aim to be clearly better: parametric geometry from SolidCraft, sets that survive
remeshing, automatic hex partitioning, undo, a text-diffable model and agent control.
The capability checklist is [docs/parity.md](docs/parity.md). Beyond the pre-processor and the
linear solver come our own explicit, CFD (lattice Boltzmann) and fluid–structure solvers (M10–M14;
methods and papers in [docs/solvers/literature.md](docs/solvers/literature.md)).

Order (revised 2026-10-13): one end-to-end slice first — *SolidCraft part → named faces → sets →
mesh → material and section → BCs and loads → static and frequency steps → Abaqus, Nastran and
LS-DYNA decks and our own solve → contour plot* — on tet meshes, so every hex mesher lands in a
pipeline that already produces solvable, verified models. Then hex: structured (sweep and mapped,
with partitions proposed automatically) before octree all-hex, because that is how analysts get
hex meshes today and it gives the best elements where stresses are read.

| Milestone | Scope | Status |
|---|---|---|
| M0 Foundation | Workspace, quality gates, FE model, command engine with rollback and panic guard, CLI, geometry boundary on SolidCraft | done |
| M1 Geometry in and surface preparation | Open `.solidcraft` designs with persistent face names, assemblies placed (done); face-tagged 3MF (done); test corpus, `cargo xtask corpus` (done); exact predicates (done); quality metrics and certified validity gate (done); weld, closed/manifold/orientation and self-intersection checks, feature edges (`modelcraft-mesh::surface`, `mesh.surface.check`, done) | in progress |
| M2 Tet meshing and size field | Size field (global, per face and edge seeds, curvature and proximity; the `modelcraft_mesh::size::SizeField` trait and edge-division helpers are in); Bowyer–Watson Delaunay (exact, symbolic perturbation, verified; `modelcraft-mesh::delaunay`, done); robust CDT boundary recovery (Diazzi et al. 2023: implicit LNC Steiner points on segments, gift-wrapping facet recovery, inside/outside labelling, B-rep face tags on boundary tet faces, few-ulp rounding repair checked by the validity gate; `modelcraft-mesh::cdt` and `mesh.tet.generate`, done: all 20 valid corpus parts); Delaunay refinement, ODT smoothing, sliver removal; tet4 and tet10 with mid-side nodes on the B-rep; mesh verify per set | in progress |
| M3 First deck | Sets and surfaces bound to SolidCraft face, edge, vertex and body names, resolved after meshing; materials (isotropic and orthotropic elastic, density) with a unit-system label and consistency check; sections (solid, shell, beam profiles) assigned by set; element formulation per region mapped to each solver; BCs (fixed, displacement, symmetry); loads (force and moment on reference points, pressure, gravity); reference points with kinematic and distributing coupling; steps (linear static, frequency) with explicit per-step load and BC tables and output presets; `model.check` naming every missing or bad item; `model.*` and `mesh.tag` commands (model definition: done); writers for Abaqus input (done: `deck.write`), Nastran SOL 101/103 (done: `deck.write`) and LS-DYNA implicit (done); the `.modelcraft` file (text definition, binary mesh, geometry references reopened on load, journal; atomic saves, autosave and recovery; undo/redo on the journal: done) | in progress |
| M4 Own solver and first results | Element library per docs/elements.md (1D and 2D first); Linear static and modal solver (tet4/10, wedge6, hex8, hex20; sparse direct, Lanczos), verified against analytic solutions (solver: done — `modelcraft-fem` kernels, `modelcraft-solver` with nested dissection, sparse Cholesky and block Lanczos, `solve.static`/`solve.frequency`/`solve.probe`, patch, cantilever, Lamé, Kirsch and beam-frequency tests; reference points with kinematic and distributing couplings and moments by master–slave constraint elimination, verified by rigid motion, clamping, Saint-Venant tension, bending and tube torsion); deformed shape, contours, mode shapes, probes, reaction sums | started |
| M5 Structured hex | 2D quad meshing of faces (`modelcraft-mesh::quad`: transfinite mapped meshes, free all-quad meshes of polygons with holes on prescribed boundary nodes, exact planar quad validity, shared `SizeField` and even edge divisions; done for planar faces); mapped hex of six-sided regions; sweep meshing; conforming interfaces and tet–hex transition; automatic decomposition into sweepable and mappable regions, proposed as SolidCraft splits | started |
| M6 Automatic hex | Octree/grid-dual all-hex for any part; hex-dominant by tet recombination; polycube for blocky parts; smoothing, untangling, boundary padding, layers through thin walls; mesh editing and orphan-mesh import | planned |
| M7 Assemblies and contact | Part instances from SolidCraft occurrences; tie between non-matching meshes; general and pairwise contact with automatic pair detection, friction; bolt pretension, springs, point masses; amplitudes, multiple steps; nonlinear static steps in decks | planned |
| M8 Materials, explicit, shells, composites | Plasticity, hyperelasticity, damage data per solver; explicit dynamics decks (Abaqus/Explicit, LS-DYNA); midsurface shells; composite layups and material orientations, continuum shells on swept hex; heat transfer | planned |
| M9 Post-processing and deck readers | Results readers for public formats (Nastran OP2, LS-DYNA d3plot, Abaqus `.fil`); XY and path plots, cuts, display groups, free-body forces; deck readers that keep unknown keywords; mesh convergence studies | planned |
| M10 Explicit dynamics | Shared element and material kernels with the implicit solver (`fem`); central-difference solver with lumped mass, stable time step, one-point hex8 with hourglass control and nodal-pressure tet4, bulk viscosity, energy accounting (X1 core: done — `modelcraft-explicit`, `explicit_dynamic` steps with initial velocities, prescribed motion and planar rigid walls, `solve.explicit`/`solve.history`, small-strain linear elastic; bar wave, rigid-wall impact, energy balance and cantilever-period tests); large-deformation materials (objective rates, J2, Johnson–Cook, damage, erosion); contact (global search, penalty with friction, rigid walls); runs on hex and tet meshes | started |
| M11 Equations of state and shells | Polynomial, ideal-gas, Mie–Grüneisen, JWL with programmed burn, tabulated; energy coupling; shock verification (Rankine–Hugoniot, Sod, Noh, Sedov); Belytschko–Lin–Tsay shells with self-contact on quad meshes | planned |
| M12 CFD: lattice Boltzmann | D3Q19/D3Q27 on grids voxelised from the face-tagged surface; TRT, regularised and cumulant collision; interpolated walls, inlets and outlets; LES; octree refinement shared with the hex mesher; wgpu backend (deterministic per device, checked against the CPU) | planned |
| M13 Fluid–structure interaction | Immersed-boundary coupling of the lattice Boltzmann fluid with the explicit or implicit structure; interface force transfer; sub-cycling; Aitken then interface quasi-Newton coupling; free-surface flow | planned |
| M14 Blast and impact fluids | EOS-driven fluids in the explicit solver: ALE multi-material or SPH, with fluid–structure contact | planned |
| Continuous: verification and validation | Every capability checked against theory (closed forms), experiments (published measurements) and published benchmarks (NAFEMS, vendor benchmark and verification manuals such as Abaqus's), each case our own model in `tests/oracle/` with its cited reference and tolerance; `cargo xtask oracle` runs them and writes docs/oracle.md; once a case matches, our result is frozen as a fixture so fidelity cannot regress (docs/verification.md) | started |
| Continuous: desktop and agents | Desktop app (viewport, model tree, commands, control channel: done; toolbar of every capability from the catalogue, ready or coming soon with its milestone, icons drawn with VectorCraft, docs/features.md: done), MCP server, browser build, command schema as the public API | started |