Two wrong-drawing bugs in SECTION 22.
1. _hex_points defaulted to start_deg=0, putting vertices at 3 and 9 o'clock,
so the plan of an M12 hex head measured 18 mm (across flats) across the
vertical while the elevation drew that same head 20.78 mm tall (across
corners e, silhouette edges at +/- e/4 - the projection of a hexagon with
vertices top and bottom). Place the two blocks in projection and the two
views of one part disagree. The default is now 30 deg, named HEX_START_DEG
and documented on both the constant and _hex_points as the convention the
elevation is the projection of, so a future fourth caller cannot pick the
other one by accident. The three top builders (_hex_fastener_top,
_hex_nut_top, _socket_head_top) inherit it.
2. _thread_feature read the pitch from params['size'] via the ISO 261 table
while drawing the geometry from params['d'], never cross-checking the two.
feature_spec('thread', {'d': 8.0, 'length': 20.0, 'size': 'M20'}) drew an M8
minor diameter and returned dims['pitch'] = 2.5 with ISO 261 cited as the
source - one thread's pitch on another thread's geometry, a silent wrong
number carrying a standards citation. A mismatch is now refused by name,
like every other check in the module. std_feature_draw's params description
says so.
Guard tests: the old top-view test asserted only len(points) == 6 and never a
vertex coordinate, so the orientation was untested. Added the vertex
coordinates, the plan-vs-elevation silhouette-height invariant across ISO 4014
/ 4017 / 4032, the socket screw's dk invariant, and the refused thread pair.
No ActiveX member is added or changed by either fix; both are pure geometry and
validation, so no live measurement is cited. The live AutoCAD could not be
probed for a confirmation run - GetActiveObject blocked past 150 s under
sibling contention.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
