TheRON
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The PROFILE record, centred assembly, and three complete arrangements: ring, spokes, fins. Each written for N members, exercised at N=3 and N=4. Failure travels as an empty profile carrying one failing check, as in the reference, so profile rejections and universal-check rejections stay in one order-sensitive list and the first failure is what surfaces. The section is cleaned before it is measured, not after. A Three-Fin section carries 17 collinear vertices from exact butt joints; they are harmless in 2D and leave zero-area triangles the tessellator cannot resolve, so measuring first would report on geometry that is not what gets extruded. Centred now carries the shifted members. Measuring a shifted shell against unshifted members reports every cavity as escaping the envelope, a leak of the whole cavity area from geometry that is fine. That trap caught me while smoke testing, so the opportunity is removed rather than documented. Verified against the oracle where the fillet does not affect the result: SPOKE_RADIUS_MM 9.1713, FIN_CORE_SIDE_MM 13.4028, FIN_SETBACK_MM 3.77783, FIN_JUNCTION_WEB_MM 2.29919, RING_CORNER_R_MAX_MM 2.87663, the ring edge vector, and both envelope dimensions all match to the recorded digit. The solvers are right. OPEN: with a junction fillet of 1.5 the Y section area is 135.572973 against a recorded 135.574, off by 0.001027 and just past the area tolerance, while every other quantity for that case matches exactly. Either the generator fillet default is not 1.5, or there is a difference of about seven parts per million concentrated in the fillet. The generator settles it. 35 tests. Nine mutations, two of which found real gaps: nothing asserted that cleaning removed anything, and the spoke zero-fillet check was untested. Oracle acceptance still skips; 236 unchanged.
Mechanical Compiler
Build the capacity to construct real structures from reclaimed and commodity materials, using whatever fabrication is actually to hand — 3D printing, tabletop CNC, welding, cement casting, COTS stock.
The reference case is a faceted timber shell: planar panels meeting along straight fold lines, converging on nodes, sitting on a platform. Buildable without a factory, provided someone has worked out what the pieces are and how they meet. That last clause is the project. The Mechanical Compiler exists to make the pieces computable, qualifiable, and reproducible by someone who was not present when they were designed.
Scope
In scope: geometry, qualification, and reproducibility of structural members and their interfaces.
Not in scope: building codes, permitting, jurisdictional approval. Qualification and compliance are different things. A qualification says this member is what it claims to be, made this way, from this stock. Compliance is a jurisdiction-specific argument someone else may build on top.
The project records physical claims, never verdicts — section modulus, moment of inertia, material provenance, process parameters. Those are what any future argument would need. A pass/fail verdict would bake in a jurisdiction we do not want to be bound to. Measure and attest; never adjudicate.
Repository layout
docs/ specification, state, failure log, roadmap
legacy/openscad/ rev 8.0.0 generators — reference, not a live target
fixtures/ frozen acceptance oracles
tools/reference-toolchain/ pinned OpenSCAD + BOSL2, build-time only
src/mechcomp/ the application
tests/ acceptance against the oracle
Read docs/ROADMAP.md first for what this is, then docs/ENVIRONMENT.md for
how an instance is built. If you are writing provisioning automation, read
docs/FAILURES.md before the specification — every entry is something a
script written from the specification alone would have got wrong.
Getting started
make deps # virtualenv, base + CAD requirements
make verify-oracle # confirm the frozen oracle is intact
make test # pytest -n auto
make verify-oracle needs nothing but Python. It should pass on any machine at
any time; if it does not, stop.
The oracle
fixtures/strap-beam-8.0.0/ holds 123 frozen cases — 113 accepted, 10
rejected — produced by OpenSCAD 2021.01 with BOSL2 at 92d697c2. It is the
acceptance criterion for any reimplementation of the generators.
The ten rejected cases are part of the contract. A port that accepts them is wrong, however good its numbers look elsewhere. It is easy to reproduce the geometry and quietly lose the constraint that made it trustworthy.
The generators under legacy/openscad/ are the reference implementation, kept
so the oracle can be regenerated. They are not a live target and the running
application has no OpenSCAD dependency.
Provenance
This project's documents, code and roadmap are LLM-generated under human direction. That is stated plainly here and in any downstream submission. We do not obscure it.
The maintainer reviews and owns every line. Anything that could not be defended in a review thread does not ship.
Licence
AGPL-3.0-or-later. See LICENSE.
Section 13 obliges us to offer source to users interacting over a network, so any deployed web tier carries a visible link back to this repository. That is a licence obligation, not a courtesy.