CIVICVS approved option 1 on 20 AUG: scale-aware bounds in test_oracle.py for SECTION_AREA_MM2, VOLUME_MM3 and MASS_G, derived from the 0.01 mm criterion and the section perimeter. Not implemented yet. Implementation, mutation testing and a green suite are one piece of work, not a partial landing.
Section 4 item 2 is removed. The F-034 measurement rewrite in FAILURES.md landed in b255ebb, so listing it as a next step sends the next reader to redo work already done. FAILURES.md keeps status Open, which is correct until the change lands.
Header commit line moved to b255ebb. Section 7 and the section 11 open-questions table now say decided rather than ready to decide.
HANDOFF.md rewritten in place, as it is meant to be. The port is complete,
so the document now describes that state rather than the work leading to it.
Most important change for whoever reads it next: the suite is 436 passed,
30 failed, and section 3 says plainly that the 30 are expected and a red
`make test` is not a broken port. Without that line the next assistant
spends its opening exchange rediscovering what is already known.
Also added: the 0.01 mm accuracy criterion as a settled decision; that
defaults are per-family and differ (ring_corner_radius_mm is 2.00 in 3x
and 1.25 in 4x); that check declaration order is the reporting order; that
params carries only a case's overrides; and pointers to PRECISION.md for
what the compiler does not do.
F-034 rewritten around measurement rather than estimate. The original Y
evidence is preserved verbatim -- it was specific and hard-won. What is
new:
- the same mechanism at 90 degree ring corners, where the expression is
exactly 12 rather than exactly 8. Rectangle: reference envelope 50
vertices, port 48.
- which side is noisy, which was previously unstated and turns out to
matter. Instrumented at %.17g the port prints half=45 raw=12 ceil=12
on every call. It lands on the integer deterministically; the
reference does not. A guard cannot make the port match noise it does
not have, so there is nothing left to try on this side.
- the scale: 30 of 113 accepted cases, 83 exact, worst relative error
2.24e-05, confined to SECTION_AREA_MM2 and its two derivatives.
- the physical magnitude: chord deviation is r*(1-cos 3.75deg), so
0.0027 mm at r=1.25 and 0.0043 mm at r=2.00. The two implementations
differ from each other by at most ~0.4 um. Two orders inside the
0.01 mm criterion.
- the constraint on any fix: the tolerance block is inside the hashed
oracle document, so the change belongs in test_oracle.py.
Status stays Open. The decision is CIVICVS's and has not been made.
Answers, in plain language, what "accurate" means for this project: the
difference between model precision, machine resolution and achieved
accuracy, and why a design file should be far tighter than any machine
that will realise it.
Scoped hard to additive and subtractive manufacturing (section 0).
Formative processes, crystal growth, lithography, joining, metrology and
surface finish are explicitly out. Section 10 asks that additions widening
that scope be refused rather than accommodated -- a borrowed tolerance
figure carries no evidence from this project while looking exactly as
authoritative as a measured one.
Section 7 states what the compiler does NOT do: no assembly layer, no
structural analysis of any kind, prismatic shapes only, no toolpaths,
verified only within its tested range. A part passing every check here may
still be structurally unsound.
Records the facets limit: at facets=48, corner radii up to 4.67 mm stay
within 0.01 mm of a true curve. Above that facets must rise, growing with
the square root of radius.
Completes the port. mechcomp.profiles.build and ProfileRejected are live,
so all 123 oracle cases execute rather than skip.
_common.py assembly pipeline shared by both families, and the eight
base checks both generators declare identically
four_x.py five profiles, all direct library calls with N=4
three_x.py six profiles; four are library calls with N=3, while
A Frame and T are built from join-layer primitives
because they are specific arrangements rather than
instances of a family
466 tests: 436 pass, 30 fail. THE 30 FAILURES ARE EXPECTED. Do not treat a
red `make test` here as a broken port.
All 30 are test_accepted_case_matches_oracle, and all 30 breach on
SECTION_AREA_MM2 alone -- VOLUME_MM3 and MASS_G are that value times 100
and times density, so each case has one underlying discrepancy reported
three times. Worst relative error 2.24e-05.
Everything that positions material is exact. ENVELOPE_X_MM, ENVELOPE_Y_MM,
MIN_WALL_ACTUAL_MM and every profile extra (AF_*, FIN_*, SPOKE_*, RING_*,
T_*) pass at 1e-4 mm in all 123 cases. Every count is exact. All ten
rejections fire correctly, including the bespoke A Frame and T paths.
Cause is F-034, now characterised precisely: the port is exact and the
reference is noisy. _circlecorner computes (90-angle)/180*segs(), which at
$fn=48 on a 90-degree corner is exactly 12. The port lands on 12.0 every
time and takes ceil 12; OpenSCAD's arithmetic lands a hair under 45 degrees
at some corners, pushing the value fractionally above 12 and the ceiling to
13. Measured on Rectangle: reference envelope 50 vertices, port 48.
There is nothing to correct on this side. Both boundaries sit within
0.0027 mm (4x) and 0.0043 mm (3x) of a true arc and within ~0.4 um of each
other -- far inside the project's 0.01 mm criterion. The tests fail because
VOLUME_MM3 is compared at 1e-4 absolute against a magnitude near 20000,
demanding 5e-9 relative agreement from discretised geometry.
Resolving that means changing the comparison policy in test_oracle.py, not
the oracle: the tolerance block is inside the hashed document and editing
it would break test_integrity_hash by design. Deferred pending a decision.
See docs/PRECISION.md for what the 0.01 mm criterion means and what this
compiler does not do.
Handoff documents were additive. HANDOFF-2026-08-19 opened by saying the
18 AUG document still applied in full and added to it. After ten sessions
a new assistant would face ten documents to read in date order and diff
mentally to work out what is currently true. That cost grows every
session and none of it is necessary.
docs/HANDOFF.md is now the only handoff, rewritten in place each session.
It is state, not a log. The dated ones move to docs/archive/ and stop
being required reading. It is standalone: everything still true from both
is carried forward.
Section 1 is invocation, stated as facts rather than demonstrated in
examples. That is the other half of the problem. runuser appeared only
inside example commands, so it could be learned by pattern matching but
not by reading, which fails exactly when an assistant composes a command
from scratch. That is what happened, and it is F-035: su cannot run as a
nologin service user, both commands returned the same message before
touching anything, and the output read as a broken repository when the
tree was clean and the suite passed. The F-027 class again.
Also stated as facts: bash tools/ not ./tools/, all repository operations
as mechcomp, Gitea SSH on 42022, pct push then chown, explicit timeouts,
journalctl not /var/log, systemd-run for long jobs, and assert the guest
is running before interpreting any pct exec result.
Not done: the same facts should be cross referenced from PROCESS.md. I no
longer had that file in view and would not patch a document I cannot see.
The shared layer is ported. What remains is the eleven catalogue
profiles and build().
Records what this session established that would be expensive to
rediscover: six-significant-figure report rounding and why VOLUME_MM3
makes it load bearing, the read-only Docker probe against the pinned
image, the oracle parameter defaults, and F-034 in full including why it
must not be fixed.
Also records the working method that earned its keep: read the pinned
source rather than recall it, mutation test every suite before landing
it, and deliver by upload rather than paste.
No behaviour change. Comments and a FAILURES entry.
The Y profile builds a section area of 135.572973 against a recorded
135.574, out by 0.001027, while every other value for that case matches
exactly. Three-Fin matches on everything including area.
Isolated by probing the reference inside the pinned toolchain image. The
hull cap is identical to nine figures, the bare union is identical, and a
single filleted pair is identical at 30 vertices and 125.699057 mm2. The
difference appears only when the three filleted pairs are combined, and
the three pairs, which are related by 120 degree symmetry and must be
identical, come back as 125.699057, 125.698029, 125.699057.
Cause proven. The arc segment count is a ceiling on a quantity that is
frequently an exact integer: a 60 degree half-angle at $fn=48 gives
exactly 8. Floating point delivers that as 8.000000000000004 on one
corner and 7.999999999999998 on the others, so one corner gets a whole
extra segment. The half-angles come from the merged polygon, whose
vertices come from the boolean kernel, and BOSL2 clipper and GEOS
disagree in the last bit.
Reproduced unguarded because the reference is unguarded. Rounding the
count before the ceiling was implemented and reverted: it makes the three
pairs identical and fixes Y exactly, and breaks Three-Fin, which had been
matching to the digit. Three-Fin has the same asymmetry and the oracle
records it. BOSL2 tipped the same way GEOS does there and the opposite
way on Y.
Two consequences for the project rather than the code. Some recorded
values encode float noise rather than geometry, so a port that is
geometrically more correct than the reference will fail those cases. And
the tolerance model may need revisiting: VOLUME_MM3 is compared at the
lengths tolerance of 1e-4 despite being area times 100 mm, so a 1e-3 area
difference becomes a 1e-1 volume difference. MASS_G is derived the same
way.
No decision yet. The number of affected cases is unknown and is the only
thing that should drive it, and that is not knowable until build() exists
and all 123 cases can run.
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.
Checks as values, the five universal checks, metrics, ProfileRejected,
and the report block. Completes the shared layer; only the profiles and
build() remain.
Report numbers are rounded to six significant figures on the way out,
matching OpenSCAD echo, which is C %g at default precision. The oracle
records what OpenSCAD printed, not full-precision geometry.
This is load bearing rather than cosmetic. VOLUME_MM3 ends in _MM3, so
test_oracle.py compares it at the lengths tolerance of 1e-4 and not the
areas tolerance of 1e-3. Volume is section area times a 100 mm length,
so an unrounded port reporting 13557.402 against a recorded 13557.4
fails by twenty times the tolerance while being geometrically correct.
Verified against the oracle: across all 113 accepted cases the recorded
volume equals the rounded area times length to within 3.6e-12, which
holds only if volume is computed unrounded and rounded at print. That is
what this layer does.
The consequence is that geometry must agree with the reference to better
than one part in a million before rounding. Near a rounding boundary a
smaller error can still tip the last digit, and that will show up as a
single case failing by one unit in the last place rather than as
something mysterious.
28 tests. Nine mutations, all caught first pass, including rounding to
decimal places instead of significant figures and computing volume from
the already-rounded area.
Oracle acceptance still skips; 236 unchanged.
Face lines, structural butt joints, hull caps, concave fillets, the
derived bore, ring fit, ring envelope and section assembly. N-generic
throughout, as the reference is.
Junctions are structural, not cosmetic: one sleeve runs through its
neighbour and is cut flush against that member the far surface, so the
two share a full-width overlap whether or not a fillet is applied on
top. The bore is derived from the members own inside-wall lines rather
than a separately scaled shape, which is what makes the declared inside
wall exactly what remains beside each cavity.
43 tests. Mutation testing found two of the reference own warnings to be
load-bearing and untested by me. A bore that has turned inside out can
carry over a square millimetre of area, so the area guard alone accepts
it and only the interior-side test rejects it. And the ring fit really
does have a spurious lower branch: a thin triangle meets a 1.2 mm web at
relative scale 0.425, where members overhang their own corners and the
solve looks converged. Both now covered.
A third mutation was malformed on my part rather than a gap -- cutting
the cavities twice is idempotent -- and was replaced with one that does
change behaviour. Nine mutations caught.
Oracle acceptance still skips; 236 unchanged.
Booleans, decomposition, area, simplicity, hull, bounds, mitred offset
and vertex cleaning. Booleans go to GEOS, which is the reason Shapely was
chosen. The decomposition does not.
BOSL2 region_parts counts by nesting parity, not connectivity: a path
takes a level from how many others contain the midpoint of its first
edge, even levels are outer boundaries, their odd children are holes.
SECTION_PARTS == 1 is an exact assertion, and Shapely agreeing with that
count is a coincidence that holds for well-formed input and not
otherwise, so the decomposition is transcribed and both the part count
and the area derive from it.
is_region_simple is treated as a manifold precondition rather than a
diagnostic. An outline that touches itself measures perfectly and cannot
be tessellated, so it must fail here and not at export.
Developed against Shapely 2.1.2 / GEOS 3.13.1, matching CT 100. Boolean
results on near-degenerate geometry can shift between GEOS releases; if
the oracle ever disagrees by one part after an upgrade, look there first.
39 tests, all arithmetic on rectangles. Mutation run found a real gap:
nothing distinguished on-boundary from outside in the nesting probe until
a shared-edge case was added. Eight mutations now caught.
Oracle acceptance still skips; 236 unchanged.
Shapely has no corner rounding, so the round_corners -> _circlecorner ->
arc -> segs chain is transcribed from BOSL2 at the pinned commit
92d697c2, read from source rather than recalled. Also deduplicate,
path_merge_collinear, is_collinear and approx, which the cleanup path
depends on.
Segment counts are contract, not a quality setting. An arc becomes
straight segments and the count sets the enclosed area, compared against
the oracle at 1e-3 mm2 -- and the extruded solid is those segments, so
this is the definition of the surface. Both generators set $fn = facets
with facets = 48 and no oracle case overrides it, so segmentation
depends on swept angle alone. A right angle gives 12 points.
round_corners raises where BOSL2 asserts, rather than clamping: silently
fitting a roundover the reference refused would diverge without any
visible failure. sb_corner_radii exists to derive safe radii up front.
33 tests. The exact-fit boundary raises rather than passing, because
tan(45) is under 1 in both languages -- a test asserting the tidy
behaviour would have looked right and been wrong. Mutation run found a
real gap: nothing exercised the three-point floor on blunt corners until
a 170-degree case was added. Seven mutations now caught.
Oracle acceptance still skips; 236 unchanged.
Vectors, GEO and MEMBER records, member placement, sleeve and cavity
paths, exact polyline distance, corner-radius derivation, and the
monotone solver. Direct translation of legacy/openscad/lib/sb-geom.scad
at rev 8.0.0.
Angles stay in degrees, matching OpenSCAD, so every expression reads the
same as its source line. The 44 solver iterations, the 0.999 and 0.98
scale factors, the 0.05/179.95 cutoffs and the 1e9 sentinel are
reproduced exactly: they shaped the frozen oracle.
Region operations are not included -- they need a 2D boolean kernel and
follow with the Shapely layer.
49 unit tests, none of which touch the oracle. Harness proven by
mutation: radians for degrees, a shortened solver, a dropped scale
factor, a skipped crossing test and a flipped offset sign are each
caught. Oracle acceptance still skips; 236 unchanged.
set -euo pipefail aborted the script on the diff pipeline one line
before the cp that restores the pre-run oracle, so --full left a
regenerated fixture file in the working tree while printing that
nothing had been overwritten. Appended || true.
Recorded as F-033. The fix is not yet exercised: the restore branch
runs only under --full and has not been entered since the change.
TheRON