stl2step 1.2.0 + SolidOut for macOS

stl2step 1.2.0 — analytic flats at construction

Engine

• Planar regions' boundary loops are ordered by an exact connectivity walk and oriented by continuity at construction, with the loop's sense taken from its own signed area. On the bundled Handle pickup fixture all four large flats build valid on the first attempt; the flange ships as its two CAD faces.
• Edge tolerances at the pcurve bind site are the exact closed-form maximum deviation plus the strict-inequality margin, at one site for planes and cylinders.
• Deterministic output under any thread count.
• Builds against OpenCASCADE 7.9 and 8.0 (the removed legacy typedef headers are no longer used).
• The four long-failing p2buildtest fixtures pass; the full suite (68 tests, including a new guard that ties the binary version to the CMake project version) passes on macOS, Linux and Windows.

Known limitations (registered, see CHANGELOG): output is deterministic per platform but not bit-identical across CPU architectures (one bundled fixture's torus-band recognition differs on x86-64 vs arm64); some seam chains still ship as mesh polylines; 27 small sliver plates reach validity through a repair pass; nine single-closed-edge inner loops are flagged by an internal assertion with no output consequence.

SolidOut for macOS (Apple silicon) — attached DMG

• Thin desktop app over this engine (engine 1.2.0 bundled with OpenCASCADE 7.9.3; no Homebrew needed).
• Signed with Developer ID Application: Joshua Roberts (L3LP86Z6L4) and notarized by Apple.
• Export STEP always opens the save panel; the last-used folder is only its starting location.
• Convert shows in-progress status under the Import | STEP pills. No floor grid.