Three defects in the orthographic view engine, all one missing idea: the engine
had no visibility rule and no single owner for the silhouette.
1. `_end_circles` inverted the hidden-line rule. Walking the bands from the
viewing end it drew a circle only when its radius EXCEEDED everything nearer,
and roled every such circle `hidden` unless it was the first band - so the one
edge that CANNOT be occluded (a step face larger than the material in front of
it) shipped dashed on HIDDEN, and the circle that really is covered was not
drawn at all. `_front_max` is now the rule: an edge of radius r at station x is
continuous when r is larger than every outer radius between x and the observer,
dashed when it is not, and it is always drawn. Bores follow the mirror image -
you see down a bore only while it stays at least as wide. Each distinct radius
is emitted once, because two coincident circles are a duplicate entity.
The same rule now roles a feature's axis-centred end-view circle, whose axial
station comes from `removal_box`; a feature that reports none keeps its own
verdict rather than having one guessed.
Ground truth by ray cast along the axis of the same solid of revolution
(segments 20x25, 40x30, 15x20; observer at +X, probe just inside each edge):
r=10 at x=75 -> first surface x=75 -> VISIBLE (was visible, kept)
r=15 at x=60 -> first surface x=60 -> VISIBLE (was HIDDEN, fixed)
r=12.5 at x=20 -> first surface x=60 -> HIDDEN (was not drawn, fixed)
2. Every axisymmetric groove was drawn twice - once as the notch
`radial_profile` cuts into the silhouette, once by the feature's own
`prims()`, which `_feature_layer` appended unconditionally. Six exactly
coincident LINEs per grooved shaft, which is precisely what
`critique.py::_check_duplicate_entities` matches, so premium rule 7 could
never be met on a part carrying a retaining or O-ring groove. `_profile_owned`
now drops a feature primitive that the body already emitted, and drops a
revolved front view's `visible` silhouette line from any feature that edits
the radial profile: the spec's rule is that grooves cut a notch in the
silhouette, and the notch belongs to the one calculation. Suppression is
"the profile already drew this", not "this feature edits the profile", so a
blind bore keeps the bottom line the profile cannot express, and an internal
thread keeps its ISO 6410 limit line.
A groove straddling a step was worse than duplicated: the feature reads one
surface radius for a span that has two, so it drew a groove floor through
solid material and left the +Y path with four odd-degree nodes. It now has
two - its two ends on the axis.
3. `build_view` validated `side` and put it in ctx, but the prismatic branch
ignored it: `side="left"` returned the right-hand view, with every feature on
the wrong side of the sheet and a symmetric outline rectangle to hide it. An
observer at -X sees screen-right = -Y, so the feature layer is now mirrored
about the outline's mid-Y. The top view is always seen from above and does
not move with `side`; that is now said in the docstring and pinned by a test.
Tests: the two that pinned the inverted rule are rewritten around the ray cast,
and one of them contradicted its own name. Seven tests added, and the prismatic
side-view test's hole moved off the y=25 mirror axis, where it could not tell a
left view from a right one. Nine of them fail against the previous `views.py`
and pass against this one.
Live AutoCAD was unavailable for a SOLPROF cross-check: the running AutoCAD 2026
(pid 40068) reports Responding=False and `GetActiveObject("AutoCAD.Application")`
never returned inside 100 s, so no scratch document was created and none is left
open. No new ActiveX member is called by this change - views.py is pure.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
