A modelled thread as other CAD systems write it to STEP has cylinder faces trimmed by helices
that turn several times around the shaft, and cylinder faces bounded by two circles with no
seam edge. The display planner refused any face whose boundary winds around its surface, so
the whole body fell back to the reference mesher, which drew those faces with triangles across
the solid.
The planner now cuts such a face along a parameter line into one period: every loop and its
copies a period apart are clipped to the strip, and the parts of the cut line inside the face
join the pieces into closed loops, with the seam nodes made once for both sides. The cut face
is meshed by Delaunay with sag refinement, and the sag check runs once more after shaping.
Bodies with a face trimmed by more than one turn take their reference mesh (picking, measuring,
the CPU viewport) from the plan too.
Tests: an ISO M10x1.5 and M12x1.75 thread built from helices, as made and after a STEP round
trip: the display mesh stays within the tolerance of its surfaces and the thread's volume, and
has no degenerate, sliver or flipped triangles.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Trimmed faces are cut into four-sided patches (squares around holes, butterflies for round faces, motorcycle traces from concave corners) and each is meshed as a Coons grid, with a cut grid as the fallback; cells are at most 2:1 along straight directions. Folded blends are refused rather than overlapped. The README lists display meshes and the gpu crate.
Rolling-ball blends now handle knife edges, where the two faces have opposite normals; an edge that runs out along an end face tangent to one side; and rounds that end in an earlier round on curved faces, picked together or one after another. The three edges at a vertex of smooth faces, rounded to one radius, end in a piece of sphere. When the given order of up to four edges is refused, or leaves a face boundary off its surface, other orders are tried.
Closes#851.
Co-authored-by: lasselian <22126420+lasselian@users.noreply.github.com>
Packs the scene's planned bodies into one GPU upload and dispatch, and evaluates intersection edges by seeded Newton refinement from a fitted B-spline through exactly solved leader points, falling back to the previous evaluation near tangency. Intersection nodes carry their faces' parameters. This changes speed, not what the app draws.
Part 4 of 4 of #303.
Co-authored-by: jyviko <2501648+jyviko@users.noreply.github.com>
Per-face target side lengths, the caller's facet angle, refined grid lines, and fixes for underflowing coordinates and straight edges ending exactly on their vertex. Nothing drawn changes yet.
Refs #303
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Irakli Kourtis