TheRON
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CIVICVS ruled on 11 SEP that the absence of an assembly layer is chosen, not unfinished. Positioning is field work. Parts made and shipped by different manufacturers have no knowledge of each other assembly tolerances, and interchangeable manufacture works because of that separation rather than in spite of it. Fit up is resolved on site against conditions no designer had. PRECISION.md section 7 now says so, and closes with read this as a boundary that was chosen, not a gap to be filled. Section 10 corrected. Its lock is on this document subject, not on the software roadmap, and it was misread that way once. Section 7 holds two kinds of entry: limits that may be lifted by work, and boundaries that were chosen and should not be. Without that distinction section 7 reads as a to do list. Section 7 also separates geometry interchange from machine instructions. An STL or STEP describes a shape; a toolpath describes what a machine should do. The first is in scope and planned, the second is not. The two sat one line apart with nothing saying they differ in kind. HANDOFF section 5 corrected: STL export needs no CAD kernel. A member here is prismatic by definition, so an STL is two triangulated caps and a quad strip. Verified in CT 100 that shapely constrained_delaunay_triangles handles a polygon with a hole correctly, area exact and no triangle inside the hole. That second check is the one that matters, because a triangulator that fills bores produces an STL which looks right in a slicer and prints solid where the conduit goes. STEP still needs the kernel. Priority order recorded with its reasoning so a successor can disagree with the argument rather than only the sequence. STL export first because it is the only item producing physical feedback. Then an authorship field in the design record, one field and a one way door. Then per member stock for the conduit core. Then persistence, which nothing has ever written despite MECHCOMP_DATA_DIR being declared since staging. Then ACL, last, because access control over nothing is machinery without a subject. A node is not an assembly. It is another artifact with declared interfaces and stays in scope. What is out of scope is positioning artifacts relative to one another. The project obligation is therefore to make each artifact interchangeable, which is what the stock descriptor and the design record already exist for.
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.