cycloidgen v7.3.1

Numbers — none. Nothing computed moves in this release: it is the 3D view's
geometry and the interpreters the package will install on.

Fixed

• Parts in the 3D view were not watertight on macOS or on VTK 9.3, so a
  section cut through them read as a hollow shell rather than as solid
  material — the exact fault 7.2.0 said it had fixed, on the two platforms it
  had not been run on.

  The cause is worth stating plainly, because it is a lesson rather than a
  slip. Faces with holes in them were filled by vtkContourTriangulator, which
  gives up part way on some inputs and reports nothing about it. 7.2.0 added a
  check for that and a list of angles to turn the face by and try again — a
  list searched, on one machine, for the smallest set that cleared every face
  this app can draw. But which inputs defeat that filter is a property of the
  build, not of the geometry: the same list left the housing full of holes on
  VTK 9.3 (which is what Python 3.10 gets) and the end cap full of holes on
  macOS arm64 at the very version it was developed on. Neither reproduces here.

  So the face is cut here now, in viz/tessellate.py, by the textbook method
  for a polygon with holes: a sweep adds the diagonals that leave nothing but
  monotone pieces, the pieces are traced out of the loops and those diagonals
  together, and each is triangulated by the stack walk. Every step is
  comparisons and cross products in a fixed order, so two machines get the same
  triangles — and the suite checks all of it directly: the whole area, no
  directed edge twice, and a boundary exactly as long as the loops.

  It is also faster, and by more than the algorithm: the triangles come back
  as indices into the mesh's own vertices, so a cap shares its corners with the
  walls that meet it and there is nothing to append and merge afterwards, and
  the cutting is remembered per mesh rather than repeated for each of the two
  surfaces every part needs. A full rebuild of the 21:1 view went from 0.18 s to
  0.11 s, and rebuilding a mesh already seen from 0.18 s to 0.02 s.

  Two things came out of writing it. Nothing in the suite had asked that a
  face's triangles all be wound the same way — and the area cannot see it, so
  a face covered twice over and once backwards passes on the sum. And the
  housing's bore is drawn as a bore arc and a pocket arc per pin, meeting at a
  point each of them computes for itself: the same point to fourteen decimal
  places, which is an edge of no length to a sweep and cannot simply be dropped,
  because the wall below the cap keeps that edge and a boundary only one of them
  keeps is a hole.

Changed

• Python 3.13 and 3.14. requires-python said <3.13 on a tree whose whole
  suite passes on 3.14, so pip install refused an interpreter the code was
  fine on. The bound is <3.15 now. An upper bound is still stated rather than
  dropped — this depends on OCCT, VTK and Qt through binary wheels, and an
  interpreter no wheel exists for is a failed install however permissive the
  metadata is — and it moved to where there is a run behind it: 3.13 and 3.14 on
  Linux, and 3.14 on Windows as well, because those wheels are built per
  interpreter and per platform. 3.12 stays the version every bundle is frozen
  on.

---

Windows - cycloidgen_..._Setup.exe. It is unsigned, so
SmartScreen will warn on first run: More info -> Run anyway. A
signed build is planned.

Linux - cycloidgen-...-x86_64.AppImage. chmod +x and run it;
it needs glibc 2.35 or newer. If it will not start, the machine has no
FUSE 2: install libfuse2, or run the file with
--appimage-extract-and-run, which unpacks it instead of mounting it.

macOS - cycloidgen-...-arm64.dmg, Apple silicon. Drag it to
Applications, then run this before opening it:

xattr -dr com.apple.quarantine /Applications/cycloidgen.app

It is signed ad-hoc but not notarized, so Gatekeeper blocks the first
launch. On macOS 15 and later the dialog it raises defaults to
Move to Trash, which deletes the install - there is no Open
Anyway in that dialog, it appears in System Settings only after a
launch has been blocked, and right-click -> Open no longer bypasses
it. Clearing the flag first avoids the dialog entirely. On an Intel
Mac, use pip.

Anywhere with Python 3.10-3.14: pip install cycloidgen, then
cycloidgen.

The numbers this produces are preliminary sizing estimates, not a
certification. Validate against a physical prototype before anything
load-bearing depends on them.